ame 441al handout - fall 2010

8/8/2019 AME 441aL Handout - Fall 2010

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To: AME-441 aL students

Attached you will find the handout package for the course. Since you are responsible for

operating within its parameters please read and absorb the material therein. During the first week

of the term, each instructor will discuss each item so it is important that you print out a hard copy

(or have the computer version on the screen in front of you) so that you can follow the discussion.

These Discussions will take place at 2 pm on August 23rd

for the Mon.-Wed. group (Prof. Radovich)

and at 10 am on August 24th

for the Tue.-Thu. group (Prof. Maxworthy). Note, the classroom for

these discussions will likely differ from that used during the rest of the semester. The locations

will be sent to you by email as soon as we know them. We hope you have a fruitful experience

and look forward to seeing you on the dates mentioned above.

Prof. T. Maxworthy

Prof. C. Radovich


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AME 441aL SENIOR PROJECTS LABORATORY

FALL 2010

Lecture: 12:30 1:50 Tuesday

ZHS 352

12:30 1:50 Wednesday

MHP 105

Laboratory: 9:00 11:50 Tuesday & Thursday

2:00 4:50 Monday & Wednesday

Professors: Dr. T. Maxworthy Dr. C. Radovich

RRB 211, (213) 740-0481 tba

[email protected] [email protected]

Laboratory Manager/: Benjamen Bycroft

Supervisor BHE 301, (213) 740-4304

[email protected]

Teaching Assistants: Francois Cadieux ([email protected])

Winston Chiang ([email protected])

Jagan Jayachandran ([email protected])

Recommended References (not required):

Beckwith, T.G. & R.D. Marangoni. Mechanical Measurements, 4th

ed, Addison Wesley.

Holman, J.P. Experimental Methods for Engineers, 7th

ed., McGraw Hill.
mailto:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]


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Important note to all students registered for AME 441aL, Senior Projects Laboratory

This semester we have close to 120 students registered for the course. In a departure from prior

years we have, for administrative reasons, had to cleanly divide the class into two more-or-less

numerically equal groups. One group meets in the lab on Mondays and Wednesdays with a

lecture/oral report on Wednesday. The other group meets in the lab on Tuesdays and Thursdays

with a lecture/ oral presentation on Tuesday. The system will be flexible enough to allow groups

to have members from different time slots the only constraints being that they communicate

effectively, that all members work on the project at least the required number of hours (6 per

week) and that the oral exam be given by all members at the same time on one of the assigned

days. All students are required to attend the oral presentations on the day for which they are

registered, Tuesday or Wednesday at 12:30 1:50 pm. Attendance will be taken and 5 points

subtracted for each absence after the first.


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Senior Projects in Aerospace and Mechanical Engineering

Fall 2010

I. Introduction

The aim of this course is to introduce the student to some of the basic ideas of experimental work. The

emphasis is on project work where one's ingenuity and initiative are a major factor in success. It is as close

as one can get, in a teaching situation, to the responsibilities of an industrial research project. It gives the

student a taste of the type of problem(s) she/he is likely to encounter upon leaving school.

Students work individually or in groups of two on a project of their choice for the entire semester.

Topics for these projects can be provided by the students themselves or selected from a number of ideas

suggested by the faculty. The extent of the subjects covered is quite broad. Project topics have ranged from

such traditional areas as fluid dynamics, structural mechanics, heat transfer, and dynamic control, to rather

obscure and arcane studies on fly-line motion, plant growth in varying pressure environments, anti-lock

brakes and the like. The primary requirement in the selection of a topic is that the student must be

interested in it. More pragmatically, design, construction and testing should be accomplished in one

semester given the constraints of the lab facilities and a set financial budget which will be discussed shortly.

Before work can begin on any project, a formal written proposal, including a timetable and budget, is

required. On Wednesday, September 1st, 2010 at 2 pm in RRB 101 the preliminary proposal is due, this

preliminary proposal does not count for a grade but is required by all groups. The final proposal is to be

submitted by Wednesday, September 8th, 2010 at 2 pm in RRB 101, and counts for 10% of your final

grade. If approved, work on the project can begin. Written group progress reports are due

every 2 weeks starting Wednesday, September 22nd in RRB 101. A few groups will be chosen to describe

their progress orally to the instructors. One Final Report, of publishable quality, will be required by each

group at the end of the term (i.e., Friday,Dec. 3rd at 5pm in RRB 101). Each group will also be required to

give an oral presentation of their work to the rest of the class. Students will be evaluated upon the quality

and content of their reports and presentation as well as their performance in the laboratory; this includes

cleanliness of work areas and attendance in the scheduled laboratory sessions.

At the end of the semester, groups with outstanding work will be asked to give oral presentations of

their projects to the AME faculty. The best of these will be awarded the John Laufer Memorial Prize that is

in honor of the founder and first chairman of the AE Department. The first and second runners-up will

receive Student Achievement Awards. These awards all include a plaque/certificate and a cash prize.

Prizewinning groups are encouraged to compete in the AIAA Western Region Student Conference. The

winner will go on to represent the region in the AIAA National Student Competition. Melissa Dixon of USC

won the national competition in 1985 with her work on a Droplet Velocity Dispersion Device. In 1987, Rick

Fournier and Ira Astrachan brought the trophy back with their paper on the Vibration Control of Nonlinear

Flexible Structures. In 1993, USC won 1st, 2nd & 3rd prizes at the Western Region Student Conference. In

1994, Steve Vargo won 1st prize at the Western Region Student Conference, and in addition, won the

national competition that year in Reno for his paper on The Deflection of Liquid Metal Droplets for Net-form Materials Synthesis. In 2000, Amy Green won 1st prize and Al Knight won 2nd prize at the AIAA Western

Region Student Conference. In the same year, Amy won the Laufer Prize for her project and the Best

Technical Award in the International Astronautics Federation Conference in Rio de Janeiro. In 2001, Amy

won 1st Place in the National Student Conference in Reno, Nevada. David Lazarra won the Laufer Prize in

2002 and Brian Bjelde and Brian Eccles won the Bleeker Award. In addition, Brian Bjelde and Brian Eccles

won 1st Place in the AIAA Western Region Student Conference in 2002 and James Parle won 1 st Place for his

project on Dynamic Soaring in 2002. The trophy is currently on display in RRB. Jonathan Hartley and


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Stephane Gallet won the Laufer Prize in 2003. In 2004, Adam Garofalo, Scott Keen, and Margaret Wharton

won the Laufer Prize. Jennifer Tsakoumakis and William Kaplan won the Bleeker Award. Zeeshan Ahmed

and Daniel Frohlich won the Student Achievement Award. Erin Wickstrand, Sergio Ibarra, and Antonio

Trevilla won the 2005 Region IX ASME Student Design Competition for their 441/442 project - bulk material

transporter. In 2008, Kedar Naik and Joe Lubinski won the second Prize in Physical Sciences, Mathematics,

and Engineering at the USC's 11th Annual Undergraduate Symposium for Scholarly and Creative Work. Also,

Benjamen Bycroft took home the first place and $500 prize at the Viterbi KIUEL Senior Design Expo. In 2009,Brennan Barker and Kevin Brashear won the Laufer Prize. Joseph Hu, Cody Ives and Mark Leffingwell won

the Bleeker Award. David Anderson and Erin Kampschroer won the Student Achievement Award. Justin

Crawford and Andrew Newman-Dilfer took 2nd place for District D in the ASME Student Design Competition.

The AME Department takes great pride in the quality of the research work produced in the Senior

Projects Laboratory. It is expected that every student will strive to produce research work worthy of

national recognition for excellence.

II. Facilities

The Senior Projects Lab has a low-turbulence, open-circuit wind tunnel. The test section measures 46 x

46 x 91 cm, and can provide freestream velocities from 3 m/s to 46 m/s with less than 1% variation from

the mean. The turbulence level is less than 0.25%. It is equipped with two force balances, both 2

components: one is capable of measuring lift and drag forces of up to 67 N and 35 N, respectively, and the

other to 12 N. Last year, as part of a Senior Design Project, a new water channel constructed. The

dimensions and capabilities of this facility are detailed in Project 10 of the Suggested Projects section.

Other facilities available for use are: a pipe flow apparatus to study convective heat transfer (in pipes);

a cross-flow heat transfer apparatus to determine the properties of various heat transfer devices (heat

exchangers) mounted in-line; a device for applying precise buckling and bending loads to rods and beams;

instrumentation to determine the dynamic vibration of various beam configurations; and an oscillating

pendulum apparatus for studying second order system dynamics, and for studying coupled modes of

vibration of various compound pendulums.

Other small facilities like drop tanks, towing tanks, and vacuum chambers are also available. In the

past, some students, working on certain projects, have been granted the use of some of the department's

more advanced research facilities.

The lab provides IBM-PCs and Apple Macintoshes for data-acquisition and computing and these can

interface with the main School of Engineering computers through the university network.

Instrumentation is available in the laboratory including low-power lasers, videocassette recorders,

high-speed cameras, hot-wire anemometers, various pressure transducers, etc. If the required

instrumentation is not readily available in the lab, they can often be procured from other departments on a

loan basis.

III. Grading

Grades are based on both individual and group performance. Marks will be assigned to all written

reports and the oral presentation. All these are expected to be of a quality that reflects the care and

professionalism with which the student conducts her/his work. Details of the requirements for all written

reports and a sample grade sheet for the oral presentations are provided in Section V and Appendices A to

D. The order of the oral presentations is to be determined by lottery.


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Students will also be graded on their performance in the laboratory. To facilitate this, as well as to help

guide the direction of each group's research, conferences with one or more instructors will be held at

regular intervals. During these conferences, current work and problems are to be discussed and evaluated.

The instructors should be notified immediately of any difficulties in the research (i.e., the type of problems

which might prevent a group from finishing the project on time), as delayed notification may have an

adverse effect on performance assessment. It is essential that these projects are worked on continuously;

they cannot be left to the last few weeks of the semester, as has often been the case in the past.

Each student is also required to keep a laboratory notebook as described in Section V. This is to be

turned in with the final report and will also be graded. This year we have put added emphasis on the

maintenance of this laboratory notebook points will be subtracted for incomplete and untidy entries. The

grade point distribution is detailed in Table 1.

Table 1. Final Grade Point Distribution

Proposal 40

Progress Reports 25

Oral Presentation 100

Lab Notebook 35Final Report 200

TOTAL 400

IV. Laboratory Procedures and Protocol

Each group can be assigned a numbered toolbox containing screwdrivers, pliers, etc. You are

financially responsible for the box and its contents! Other tools such as drills, circular saws, etc. are

available in the supply room and must be signed out and returned as soon as possible as they may be

needed by other groups. Instrumentation and computers must be signed out and returned upon

completion of the project.

When requesting equipment, students must be prepared to give all the pertinent characteristics they

require so that the staff can act on the requisition effectively. On some occasions, it becomes necessary to

share some equipment with other groups. Under these circumstances all parties involved are expected to

be considerate and cooperative.

Students are allotted approximately $75.00 each for the purchase of expendable materials. The total

amount of funding for a project will be based on the budget submitted with the proposal and may exceed

this amount considerably if it is deemed necessary for the project's success. Purchases from outside

vendors for more than $50 require a Purchase Order (PO) and may involve 2-3 weeks delay. Therefore,

these purchases must be made well before they are needed. The student may make smaller cash purchases

and she/he will be reimbursed upon presentation of an original receipt. Items from the Engineering

Machine Shop (KAP Basement), Electronic Store (OHE 246), and Chemistry Store (SGM 105) can only beobtained on a Department Order (DO). Cash purchases from these places will not be reimbursed. All

expenses to be paid by the university must be approved by Drs. Maxworthy or Radovich, who must also

sign all receipts, PO's and DO's before reimbursement is allowed. No reimbursements will be made if these

procedures are not followed.

According to the University rules, students are not allowed to work in the laboratory without

supervision. Therefore, all experiments must be performed within the scheduled lab time.


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AME-441 Laboratory Protocol

Space Management

Store your personal belongings out of walking paths under work tables for instance. It is

important to keep a clear and safe walkway through the laboratory.

Keep the lab clean. No food or drinks in the lab area. You are welcome to have food or drinks in

the hallway, near the stairs, or in the BHE301 presentation room (outside of AME341 lab hours).

At the end of the lab return all lab equipment to its original location (cables, beakers, measuring

devices, drill bits, etc.

There is a small engineering library in the BHE301 presentation room. These resources are to be

shared and are not to leave the BHE301 presentation room.

Supply Room and Device Access

Access to the BHE301a supply room is allowed only with supervision and approval of an AME441

faculty/staff member.

Any/all resources and devices that leave the Supply Room mustbe approved, checked out, and

signed for by an AME441 faculty/staff member.

Safety precautions (gloves, eye protection, etc) are a requirement. Please ask a faculty/staff

member if you are unsure of any safety precautions you should be taking when working in the lab.

Please report any/all broken or non-functioning equipment and devices to faculty/staff. This is

extremelyimportant, and will save everyone time and trouble in the future!

When requesting to have parts fabricated/machined, ensure that your designs are complete

design by trial and error will not be allowed. Be prepared to thoroughly present and explain your

design in order to facilitate the approval and scheduling of part fabrication/machining.

Computer/Printing Rules

Login Name: JStude Password: AMElab

Do notcustomize any computer workstations. This includes modifying the desktop, any/all

computer settings, installing any software without approval from faculty/staff.

Save files onlyin the following directory: D:\home\JStude. Files in other locations will be

deleted.

portable storage device.

Printers are available only for printing of assignments, reports, and required usage for AME441.

This does not include lectures notes, or reprinting of materials provided to you.

When done with a computer workstation, log off and turn off the monitor.


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V. Reports

The first written requirement is a Project Proposal. It should include a cost estimate and a timetable.

Only one per group is required. The deadline for submission of the final proposal is Wednesday,

September 8th, 2010 at 2 pm in RRB 101 . Students are encouraged to submit their preliminary proposals as

soon as possible since in some cases it is necessary to modify the proposal before it can be approved.

Proposals will not be graded until after the submission deadline, so any corrections made before the

September 8th deadline have no bearing on the final evaluation.

It is not uncommon for proposals to be rejected. Students whose projects are not approved will be

given an extra week to submit a new proposal but can no longer receive full credit. Work on the project can

begin as soon as the project is approved. A suggestedformat for the proposal can be found in Appendix A.

A progress report is due every other Wednesday before 2 pm, starting September 22 nd, 2010. Only

one per group is required. It is anticipated that, in all, five progress reports will be handed in through the

semester. These should detail all work that the group has performed in the preceding two weeks and lay

out the expected tasks for the following two weeks. It can and should include figures, graphs of preliminary

data, etc., if these are deemed by the group members to be important for the proper assessment of their

work. These will be graded mainly on the amount of progress achieved by the group. The suggestedformat

for the progress report can be found in Appendix B. On the following Monday or Tuesday, at 2pm and 9am,

respectively, a few groups will be chosen to give an oral progress report to the instructors.

The Final Report is due Friday, December 3rd, 2010, at 5:00 pm in RRB 101. Each group is required to

submit one final report. Late reports will be penalized (-10 points per day, including the weekend). The

suggestedformat for the final report can be found in Appendix C. Although one Final Report is turned in

per group, each student is required to submit the Peer Evaluation Form found in Appendix E. Print this

form and hand it in Friday, December 3rd, 2010, at 5:00 pm in RRB 101. There will be separate drop boxes

for the peer evaluation forms and the final reports.

Each student is also required to maintain a laboratory notebook. It should contain all possible

methods of solving problems that arise, as well as the details of these problems. Raw data, calculations,construction and set-up drawings, uncertainty analysis, etc., should all be contained in this notebook. It

should be kept neat and legible so that an individual assigned to take over the project at a later time can

easily continue the project. In the back of the notebook, a log of hours spent on the project should be kept

as well, with a brief description of what was done at particular times. This notebook is to be submitted

with the final report and will be graded rigorously.

As mentioned earlier, the order of oral presentations is to be determined by lottery. Presentations will

be 20 minutes long total, including questions. The standard visual aid to be used will be a computer plus

projector, but a Vugraph projector can be ordered several days in advance. A sample grade sheet for the

oral presentation can be found in Appendix D.

All students are expected to attend the oral presentations, starting on a date to be determined, thatwill be held in the assigned lecture classroom, on Tuesdays or Wednesdays at 12:30 p.m. You are required

to attend the Lecture session you registered. Attendance will be checked! Anyone with more than one

absence will lose 5 points off the final grade for each absence after the first.

All reports are to be typed and stapled or clipped. The use of fat, three-holed binders is discouraged

because, in large numbers, they are cumbersome for us to handle. Progress reports should be submitted

loose leaf or stapled if they exceed one page. Include date, title, project number and names of the

authors.


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Appendix A: Suggested Format for Proposal

Section Title No. of Pages

1. Introduction/Historical Background 1

2. Theory/Basic Equations 1-3

3. Experimental Setup/Procedure including a sketch of the

apparatus as well as details of the calculations needed to

design the apparatus in a logical way.

1-4

4. Cost Estimate (in duplicate) 1

5. Timetable (in duplicate) 1

6. Reference List 1/2

Comments: The objective of the proposal is to convince the reader that your project will provide

useful information and can be done within the time, budget, and other constraints given. Theinformation/knowledge that one stands to gain from it is, of course, not expected to be of the sweeping,

general, great-benefit-to-mankind type, but rather to be specific and limited in scope.

The reader should be convinced that you know what you are talking about in terms of information

currently available on your topic and what you want to do to advance this knowledge. Your goal must be

explicitly stated. Mention previous work and give legitimate reasons for conducting the experiment.

You should also have a clear picture of how you are going to conduct your experiment. Perform rough

calculations to enable you to design your apparatus in a logical manner and to estimate, roughly, the

magnitude of your expected results, i.e., try to determine what you need by calculation rather than just

guessing. What facilities and equipment will you be using? How large will the model be? What are the

important parameters? What kind of data will be taken? You should have researched your topic in enough

detail and performed some initial calculations to be able to answer these types of questions. Include a

sketch of the set-up as you imagine it will be as well as calculations, graphs and figures that will help

explain what you want to do.

Sections 4 and 5 should be written on separate sheets in tabular form.

Remember to write your proposal in a manner that can be easily followed by a reasonably competent

engineer who is not necessarily specialized in your project's field. A good rule is to define any terms or

concepts that you were not familiar with before you started your literature search. As a test, have one of

your classmates (not a groupmate) read your proposal to see of she/he understands, and can picture what

you want to do!


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Appendix B: Format for Bi-Weekly Progress Report

Title of Project

Names of Group Members

Progress Report for the Period Starting MM/DD/YY and Ending MM/DD/YY

Progress reports should be written in third person past tense, as all formal reports should be. The task

of writing the progress report for the group should be distributed evenly among the group members.

Include calculations, sketches, and other useful information that will help the staff assess your progress.

These reports will be graded partially on form (15%) but mostly on content and the amount of progress you

have made.


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Appendix C: Suggested Format for Final Report

Section Title No. of Pages

Abstract (on title page) 1

Introduction 1-2

Experimental Technique 2-3

Results 3-5

Discussion 3

Conclusion 1

References 1

Appendices No more than 5

Note: No more than 20 pages of typed double spaced text. No more than 25 pages total.

Comments: Assume the reader knows nothing about your work! The final report should stand

alone with no references to your proposal or progress reports. (You may of course reference other

papers or books.) The introduction should state the goal/objective as well as give some historical

background and/or the state of the art of the subject.

The experiment technique section should give the important details of the set-up ( a sketch must

be included) as well as the procedure. Mention all the equipment used, type of the data taken, how

the data was processed, etc. When writing this section, keep in mind that you want to give the reader

the impression that you were careful when you took your measurements and your data is reliable.

Towards this end you can mention your estimates of uncertainty and accuracy without going into

excessive detail. (Detailed uncertainty analysis can be put into an Appendix and should definitely be

in your lab notebook!!!) Do not go into a narration of all the trouble you went through to get to yourfinal set-up!

Results and Discussion can be two separate sections or one. It can even be subdivided into the

different aspects of the investigation. The only requirement is that you present your results and then

discuss them in a manner that can be easily followed. This is by far the most important part of your

report and should be worded carefully so as to enhance the virtues of your work.

In the Conclusion, assess whether you have achieved your goal/reached your objective as stated

in the Introduction. You may restate your important findings briefly. Also, talk about improvements to

the work and applications.


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Appendix D

AME-441 Senior Projects Laboratory

Oral Presentation Grade Sheet

Date:

Title of Project:

Name(s) of Speakers:

Grade for each category is based on the scale shown below.

Grade Comments

1. Organization and Delivery

(Was project clearly defined?

Continuous thoughts? Speech easy to

understand? Visual aids: sufficient

number of slides, neatness, clarity, etc.)

(30)

2. Technical Content

(Scientific merit appraised? Symbolsand parameters defined? Technically

sound arguments? Logical methods of

experimentation and evaluation? Etc.)

(50)

3. Overall Performance

attention? Questions answered, etc.) (20)

Total Score

(100)


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Appendix E

AME-441 Senior Projects Laboratory

Peer Evaluation Form

Although one Final Report is turned in per group, each student is required to submit the following Peer

Evaluation Form. Turn this form in Friday, December 3rd, 2010, at 5:00 pm in RRB 101 . There will be

separate drop boxes for this form and the final report.

Use this form to evaluate the contributions made to your AME-441 Senior Project by all members of

your group (including yourself). In the table provided below, print the names of all group members and

assign a score for each performance category. Rank each category on a scale of 0 to 4 (0 being the lowest;

4 being the highest); don't forget to rate your performance as well. You may also provide specific

comments for each team member in the space provided. The scoring guideline is as follows:

0 = Poor performance in this area

1 = Below average, rarely met expectations

2 = Average, fulfilled expectations of the group

3= Above average, occasionally exceeded expectations

4 = Outstanding! Often exceeded expectations

Title of Project:

Team Member

NAMECooperation Dependability Participation

Quality of

Work

Interest and

Enthusiasm

your

nameComments:

Comments:

Comments:

Comments:


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Suggested Projects

Fall 2010

Project 1. 2011 ASME Student Design Competition. H2Go: The Untapped Energy Source?

Advisor: Prof. G. Shiflett Difficulty: Difficult

The 2010 ASME Student Design Contest information, H2Go: The Untapped Energy Source?, is now

posted at:http://www.asme.org/Events/Contests/DesignContest/Student_Design_Competition.cfm

Project 2. Sandstorms and Solar Panels

Advisor: Profs. G. Spedding and C. Radovich Difficulty: Moderate to Difficult

The Department of Water and Power proposes to cover a large expanse of Owens Lake with solar

panels. Read:http://www.reuters.com/article/idUSTRE61A04M20100211 . Owens Lake has been drained

by usage from metropolitan LA, and DWP currently sprays water over the dry bed to reduce the intensity of

sand/dust storms. The presence of solar panels may help to trap the water and keep the atmosphere

moist, as well as generating electricity. The question arises now, how should the solar panels be

constructed and arranged so that their operation is not compromised by the wind-driven dust.

A general question might be: how does one arrange an array of multiple flat plates so that ground dust

is not lifted onto their faces when the winds rise? Lift them up? If so, then how high? Put wipers on them?

Have solar-powered mini-blowers on them? Have them tiltable so they can clean themselves? Some of

these ideas have merit, others not. Experiments in a water channel or in the student wind tunnel can be

formulated to investigate this problem.

Research items include: composition of dust, strength of wind, calculation of atmospheric boundary

layer thickness, scaling of appropriate experiments. Design elements include: number and geometry of

plates and their degrees of freedom, dust removal or prevention strategy, simple decisive test to answer

specific questions, given the design.

Project would include a field trip.
http://www.asme.org/Events/Contests/DesignContest/Student_Design_Competition.cfmhttp://www.asme.org/Events/Contests/DesignContest/Student_Design_Competition.cfmhttp://www.asme.org/Events/Contests/DesignContest/Student_Design_Competition.cfmhttp://www.reuters.com/article/idUSTRE61A04M20100211http://www.reuters.com/article/idUSTRE61A04M20100211http://www.reuters.com/article/idUSTRE61A04M20100211http://www.reuters.com/article/idUSTRE61A04M20100211http://www.asme.org/Events/Contests/DesignContest/Student_Design_Competition.cfm


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Project 3. Flow on a Rotating Disc

Advisor: Prof. T. Maxworthy Difficulty: Moderate

Several variations of this project are possible. One will be described here; others can be discussed in

conference with Prof. Maxworthy.

These flow types have several interesting applications. Foremost is their use in industrial spray-painting situations, e.g., automobile painting. A number of artists have used the technique to produce

interesting abstract paintings. The technique is used to manufacture thin films for various applications.

In the present case, a rotating disc has a circular dam placed at its center. Fluid fills the space behind

the dam to a known depth. The disc is then rotated at known rotation rate, the dam is raised and the fluid

moves radially outwards. The position of the front is measured as a function of time. When the disc is not

rotating, the theory for the front motion is well known. As far as we know, this is not true for the rotating

case. The similar problem of a two-dimensional sheet of fluid flowing down a slope is also well studied and

has shown that the front becomes unstable, as depicted below. Is this scenario possible for the rotating

case?


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Project 4. Thermals with Negative Buoyancy


Most applications of thermals consider the case where the buoyancy acts in the direction of the initial

motion; e.g., clouds, forest fires, etc. In the opposite case, the buoyancy acts to oppose the initial

impulsive motion; e.g., in volcanic explosions or, in some plants that broadcast their seeds by ejecting them

vertically. The following two projects look at slightly different models for these processes:

Project 4A:

In a tank of fresh water, generate a vortex ring of salt water. If the initial velocity is U, the hole

diameter D and the density difference , then one would expect that the flows would be different for

large or small values of U2/ (a Froude number). For large values, a vortex ring should form initially

which then collapses as the ring slows. For small values, a dense puff of heavy fluid forms that soon

reverses and falls to the bottom of the tank. Photograph the history of the thermal motion and determine

how its velocity varies with time. A typical apparatus is shown below but there are other ways to generate

the initial ring that you might want to consider.

Project 4B:

In air, project a small volume of a granular material vertically upwards with velocity U. Observe the

motion photographically for various cases of velocity, volume and density. A possible type of gun is shown

below although other designs might be better. See TM for photographs of seed pods bursting and thereby

broadcasting their seeds.


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Project 5. Particle Size Distribution Measurement Using a Weighing Technique

Advisor: Prof. T. Maxworthy Difficulty: Moderate to Easy

There are several methods for determining the distribution of diameters of a particle mixture. One

that can be easily implemented is to make use of Stokes law for the velocity of a given diameter and

accurately measure the weight as a function of time of a sedimenting cloud as it impinges on a plate at the

bottom of a fluid column. Set-up such a system using an existing electronic balance, as shown below.

Measure the distributions of a number of commercially available powders.

Project 6. Dynamical Systems Approach to the Dynamics of Swimming Animals

Advisor: Profs. E. Kanso and T. Maxworthy Difficulty: Moderate to Easy

It has been demonstrated computationally that a simple linear system of springs and spheres, shown

below, can move indefinitely in an inviscid fluid when the central sphere is set into oscillation. Clearly this

will not be true in a viscous fluid but at least an initial, decaying, lateral movement should be seen. Setup

such a system in water, and test to determine if there is some initial condition that allows a forward motion

that decays relatively slowly.


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Project 7. Modeling Sound Refraction and Diffraction in a Ripple Tank

Advisor: Prof. T. Maxworthy Difficulty: Moderate to Difficult

A ripple tank (Google: Ripple Tank to view a wide range of simulations) can be used to simulate

acoustic phenomena at speeds that can be easily observed. Set up such a tank to observe a simple point

source and how the wave field strength varies under various circumstances. These might include:

diffraction around a wall, as a simulation of a freeway sound barrier, refraction at a change in depth, the

sound radiated by a jet, (http://blog.cfdlab.net/2007/03/fluid-dynamics-videos.html ), etc. You will need to

devise a method of accurately measuring wave amplitude as well as to photograph, and/video, the wave

crests. The picture below is only for information purposes only; it is not exactly what is needed for this

project.
http://blog.cfdlab.net/2007/03/fluid-dynamics-videos.htmlhttp://blog.cfdlab.net/2007/03/fluid-dynamics-videos.htmlhttp://blog.cfdlab.net/2007/03/fluid-dynamics-videos.htmlhttp://blog.cfdlab.net/2007/03/fluid-dynamics-videos.html


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Project 8. The Dynamics of Swimming Fish

Advisor: Profs. E. Kanso and T. Maxworthy Difficulty: Moderate

Analysis of the tail motion of a swimming fish show that it consists of two parts. The tail swings

through a relatively large angle about a point that at the same time oscillates laterally, as shown below. Set-

up an apparatus that consists of two very-low friction sliders set at right angles. The lower one is fixed to a

solid base and presses against a load cell that measures the thrust generated by a flapping tail. The second,

at right angles to the first, is attached to the tail pivot and drive motor. As the tail oscillates the lateral force

generated, i.e., the one that is perpendicular to the thrust component, moves the pivot point back and

forth laterally. This motion must be constrained either by springs, inertia or friction to limit the magnitude

of the lateral motion. A possible concept is shown below. A version of this has already been built. It needs

to be tested to be sure it operates properly and several tail units need to be attached to determine which is

the most efficient.


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Project 9. Two Projects on the Swimming of Penguins


These animals are basically neutrally buoyant in salt water and hence mainly need their flippers for

propulsion. Two possible projects present themselves in order to be able to calculate their swimming

ability.

Project 9A:

The penguin video (http://people.eku.edu/ritchisong/RITCHISO//554notes3.html ) that I have shows

that the fin motion is such that it can generate a considerable thrust on both the up-stroke and the down-

stroke; see the sketches below. From the video one can measure the flipper dimensions (L and c),

frequency () and angle () as well as body velocity (U). This allows the calculation of typical values of the

governing non-dimensional quantities: flipper Reynolds Number ReF = Uc/ where is the kinematic

viscosity of water; Reduced Frequency, = c/U; flipper aspect ratio, c/L, and flipper angle of attack ().

Values for other animals can probably be found in the literature.

Construct an oscillating flipper system in a way that it can be used to visualize the flow around the

flipper and in the wake.

Project 9B:

In collaboration with the team working on Project 2 above construct a system to directly measure the

thrust generated by the oscillating flippers over the range ofReF, and .
http://people.eku.edu/ritchisong/RITCHISO/554notes3.htmlhttp://people.eku.edu/ritchisong/RITCHISO/554notes3.htmlhttp://people.eku.edu/ritchisong/RITCHISO/554notes3.htmlhttp://people.eku.edu/ritchisong/RITCHISO/554notes3.html


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Project 10. Use of a Small Water Channel to Test Various Model Designs


The water channel originally used in the AME 441 lab was retired some time ago. A replacement has

recently been built for future experiments in BHE 110. A sketch of the design is shown below. Construct at

least two models to demonstrate some basic flow features. For example: a) visualize the flow around a

cylinder and measure the forces at various Reynolds numbers, b) visualize the flow around an airfoil at

various angles of attack and measure the lift and drag forces.

In these experiments, the two groups working on them should collaborate to build a common force

balance to measure two orthogonal forces.

Project 11. The Stability of a Shocked Interface

Advisor: Profs. T. Maxworthy and V. Eliasson Difficulty: Moderate

When a pressure pulse (shock wave) passes through an interface (e.g., from water to air) it causes a

disturbance which, as far as I know, has not been studied in detail. Set up an apparatus to study this using

bottom of the tube generates the shock wave and a high speed camera is used to record the resulting

disturbance.


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Project 12. Two Projects on the Drag of Cylinders with Modified Surface Finish

Advisor: Prof. T. Maxworthy Difficulty: Moderate to Easy

The Drag coefficient (CD) of a circular cylinder is well known as a function of Reynolds Number

(Re = UD/) (See Fluid-dynamic Drag by H. Hoerner for a general survey. Prof. Blackwelder has a copy). At

moderate Re less than 105 the values are well behaved, consistent with a value of CD = 1.2. Beyond this

critical value the drag depends on other parameters especially surface roughness. At very high Re of order

106 and beyond the value depends weakly on Re at a value of about 0.3. Sphere drag behaves similarly,

however a test with trip wires has shown that the high Re result can be simulated at sub-critical Re

("Experiments on the Flow Around a Sphere at High Reynolds Numbers," J. of App. Mech., v.36, No. 3, pp

598-607. September 1969).

Project 10A:

Extend the older sphere result to the case of a cylinder. In the wind tunnel, set up a cylinder with and

without wire trips of different diameters, as shown below. Measure the drag coefficient under a variety of

circumstances ofRe, trip diameter/cylinder diameter and trip location.

Project 10B:

Clearly the trip wire technique only works well when the flow direction is as shown above. When tryingto reduce the drag on a cylindrical chimney for example one needs a method that is omni-directional. One

solution is to place twisted strakes around the cylinder, as shown below, so that the trip wires are not

facing in any one direction.

Set up a cylinder with spiral trip wires of various diameters and pitch angles. Measure the drag at

various Rethis may be a little

more complicated and consume too much time.


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Project 13. The Sequestering of Liquid CO2 in a Porous Medium


Project 13A:

Recently suggestions have been forwarded, and worked on, to inject CO2 into deep porous layers in

order to reduce the amount of this greenhouse gas in the atmosphere. Porous media can be modeled in thelaboratory by a, so-called, Hele Shaw Cell. This consists of two transparent plates spaced a small distance

(e.g., 1 mm) apart and viewing the resultant viscous flow in essentially two-dimensions. Paradoxically this

. The question to

be answered is: How does the injected fluid spread under a variety of circumstances? A small apparatus

the shape-history of the injected fluid as a function of: Flow rate; viscosity ratio; density ratio, i.e., how

important are gravitational effects; changes in the permeability of the porous medium. The latter effect can

be simulated by changes in the width of the gap between the plates (see Part B).

override and viscosity-Experiments in Fluids, v 44, pp 781-794 (TM canprovide the group(s) with copies of this paper).

Project 13B:

Almost always, the rock formations into which the CO2 is injected are layered, i.e., layers of various

thicknesses and porosities are stacked one on top of the other. How does this affect the history of the

shape of the injected patch? In a variation of the apparatus shown in the sketch introduce several strips of

thin plastic that restrict the width of the gap in a known fashion. In a porous medium the velocity

U = -(K/)p while in the HS cell it is -h2p/12. Thus, theoretically we know that the permeability Kvaries

as h2/12, where h is the gap width and is the fluid viscosity. Introduce a steady supply of fluid and

determine how the flow interacts with the change in K; i.e., h2. We can discuss the best fluid(s) to use to get

the most interesting results.

TYPICAL HELE SHAW APPARATUS


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Project 14. Data Storage and Processing for Mechanical Damage Detection in Structural Systems

Advisor: Prof. F. Udwadia Difficulty: Difficult

This project deals with developing a system of hardware and compatible software to:

1 Monitor the acceleration of a system (the tip acceleration of a clamped cantilever beam subjected

to ambient vibrations)2 Transmit by wireless the acceleration record to a digital storage device.

3 Take the data over a moving time window and find its Fourier Transform to pick out the resonant

frequencies (say the lowest 5), on a continuous time basis.

4 Monitor changes in the resonant frequencies when the system is subjected to large amplitude

(and potentially damaging) vibrations.

5 Develop the capability to track and detect changes in the resonant frequencies, and when these

-alert for the system.

A flexible cantilever beam, clamped at one end, is used as a prototype mechanical system whose

health monitoring is desired. On the tip of the beam is mounted an accelerometer capable of wireless data

transmission to a server (or digital recording device). Using suitable software (Matlab, for example), datafrom the storage device is used to calculate the Fourier Transform of the signal and identify the resonant

frequencies of the beam from its response to ambient excitations. These resonant frequencies are

continuously tracked in time, and when large changes in them occur (indicating mechanical damage), a

damage-alert is delivered by the software.


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Project 15. Heat Transfer from a Heated Object

Advisor: Prof. T. Maxworthy Difficulty: Easy

We have available a commercial wind tunnel designed to look at heat transfer from a heated cylinder

in a bundle array. Reference: any textbook on Heat Transfer

Project 15A:

Design a rotating, circular-cross-section test-cylinder to be placed in the test section and measure its

heat transfer characteristics over a range of parameters. Especially include the non-rotating case so you can

compare with available data.

Project 15B:

Design a new test section to measure the HT properties of single cylindrical objects, e.g., triangular,

square, random cross-sections.


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Project 16. Breakup Radius of a Disturbed Liquid Sheet

Advisor: Prof. C. Radovich Difficulty: Moderate to Difficult

As depicted in the figure below (from Clanet and Villermaux 2002), an axisymmetric radially expanding

liquid sheet can be produced by directing a laminar jet of water onto a stationary flat disk. In this figure, U

is the velocity of the incoming jet, D is the jet diameter, and Di is the diameter of the impact disk (D < Di).The edge of the sheet is defined by the radius R, where the sheet disintegrates into droplets. G. I. Taylor

derived the following analytical expression for the breakup radius using the density of water (), volume

flow rate (Q) and the surface tension of water against air ().

Through experimentation, J.C.P. Huang determined that the breakup radius of a radially expanding

liquid sheet varied with the Weber number a dimensionless ratio of inertial and surface tension ()

forces, . Huang found that the breakup radius followed when .

Note, instead of using an impact disk Huang impinged two coaxial streams. Thus, which,

when applied to Eq.1, aligns

Both Taylor and Huang found that measurements of the breakup radius were typically some value less

than that predicted by Eq.1. It is believed that disturbances imposed on the liquid sheet produced this

result by accelerating the disintegration process. Some possible sources are the surface roughness of the

impact disk and/or vibrations in the water jet delivery system.

The goal of this project is to determine what effect external disturbances can have on the breakup of a

radially expanding liquid sheet. The impact disk and a controllable means for disturbing the liquid sheet

must be designed and implemented; an array of nozzles and a water reservoir already exist. Test variables

may include the disturbance frequency, disturbance strength and the Weber number. Measurements ofthe breaks radius can be made with images from a high speed camera.

References-340.

--319.

Society of London 253A (Dec. 15, 1959b): 296-312.

Society of London 253A (Dec. 15, 1959c): 313-321.


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Project 17. Object Detection and Image Focusing

Advisor: Prof. C. Radovich Difficulty: Moderate to Difficult

Consider a camera and lens setup that has a finite depth of field. The depth of field represents a

distance from the focal plane Using centimeters as the unit of

length, thefocal plane is located, by definition, at cm. Any object located outside of the focal plane

() will appear blurred, as shown in the figure below.

Given that the depth of field is finite, if an object were randomly placed into the field of view it will

likely be out of focus. The goal of this project is to design an apparatus (and image analysis routine) that

can detect object and bring it into focus. This experiment will be restricted to an optical setup

with afixed focal length. Some possible design considerations include the size of the object of interest and

motion of the object in the (x, yand z).

Project 18. Design and Test a Tribometer

Advisor: Profs. G. Shiflett and C. Radovich Difficulty: Moderate

A tribometer is a measurement device that

estimates the kinetic friction between two sliding

surfaces. One variation of a tribometer is the

-on-

system presses a pin onto a rotating disc; the

load applied to the pin (onto the rotating surface)

in precisely known and the resultant force

applied to the mounting arm is measured to

reveal the kinetic friction of the system.

Design and construct a tribometer and

determine the kinetic coefficient of friction

between various materials. Some design

considerations include the applied load, rotation

rate, variations with temperature and contact

surface area. (image from nanovea.com)


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Project 19. Drag Coefficient of a Water Droplet

Advisor: Prof. C. Radovich Difficulty: Difficult

Consider the following problem: Suppose a sphere of diameter dhad fallen vertically (in the direction

of gravity) from height z1 to z2, and the initial velocity at z1 was U. What will the velocity of the sphere be at

height z2?

This problem can be solved analytically provided the mass and drag coefficient (Cd) of the sphere are

known. Given the diameter and material composition of the sphere, the mass is relatively easy to

determine. However, the drag coefficient is not a constant but is a function of Reynolds number, Cd(Re).

For a rigid sphere, this problem has been studied extensively and is documented in Clift, et al. As shown in

this text, the solution for Cd(Re) is a piecewise set of equations for specific Reynolds number ranges. Recall,

Re = Ud/, thus, Cd changes with the velocity of the sphere (which changes with time). Therefore, the

analytical solution is obtained by solving for the forces acting on the droplet in small time increments (t).

The velocity with respect to time will yield the total displacement and ultimately, the velocity after traveling

a specific distance (e.g., z = z1z2).

A similar drag coefficient vs. Reynolds number correlation is desired for water droplets. Waterdroplets in static equilibrium are spherical in shape; however, they tend to deform when subject to a

flowing air stream (as shown in the image below). This deformation augments the frontal area of the

droplet and increases the drag coefficient. To verify this, a simultaneous drop test of a water droplet and a

rigid sphere (of comparable size and mass) could be performed to show a difference in velocities after

traveling a given distance.

The goal of this project is to estimate CD(Re) for a water droplet. Similar to the rigid sphere

correlation, this estimate will likely be a piecewise set of equations dependent on discrete Reynolds

number ranges. Perhaps a water droplet shape correction factor can be applied to the spherical CD(Re)

correlation? One method of producing and imaging water droplets is sketched below; however, a wind

tunnel investigation may also be performed. Using a high speed video camera, sequential images could be

used to estimate the droplet velocity and acceleration as well as the droplet size.

References

Clift, R., J.R. Grace and M.E. Weber. Bubbles, Drops and Particles. New York: Academic Press, 1978.

Magono, C. On the Shape of Water Droplets Falling In Stagnant Air Journal of Meteorology, Vol. 11, 1954.http://journals.ametsoc.org/doi/pdf/10.1175/1520-0469(1954)0112.0.CO;2

Spilhaus, A.F. Raindrops Size, Shape and Falling Speed Journal of Meteorology, Vol.5, 1948.

http://journals.ametsoc.org/doi/pdf/10.1175/1520-0469(1948)0052.0.CO;2
http://journals.ametsoc.org/doi/pdf/10.1175/1520-0469(1954)011%3C0077:OTSOWD%3E2.0.CO;2http://journals.ametsoc.org/doi/pdf/10.1175/1520-0469(1954)011%3C0077:OTSOWD%3E2.0.CO;2http://journals.ametsoc.org/doi/pdf/10.1175/1520-0469(1948)005%3C0108:RSSAFS%3E2.0.CO;2http://journals.ametsoc.org/doi/pdf/10.1175/1520-0469(1948)005%3C0108:RSSAFS%3E2.0.CO;2http://journals.ametsoc.org/doi/pdf/10.1175/1520-0469(1948)005%3C0108:RSSAFS%3E2.0.CO;2http://journals.ametsoc.org/doi/pdf/10.1175/1520-0469(1954)011%3C0077:OTSOWD%3E2.0.CO;2


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Project 20. Tunable Shock and Vibration Test Device

Advisor: Profs. C. Radovich and V. Eliasson Difficulty: Easy to Moderate

Shock testing is commonly performed during the qualification phase of any structure that may

experience an impact or rapid acceleration (e.g., a laptop case, spacecraft payload, etc.). This type of test is

performed by striking the structure with large mass. For example, a swinging hammer can be supported

above the structure and then released to provide a shock to the test subject. The strength of the impulse

is measured by an accelerometer where, the amplitude is typically expressed as a multiple gravitational

acceleration

When a structure is exposed to this type testing, it is usually tested at specific shock amplitudes

corresponding to events or scenarios it is likely to experience. Examples include: a 1g shock test of a cargo

box (to simulate an accidental drop) or, a 10g test to simulate an explosive bolt used during stage

separation of a spacecraft. Therefore, it is desirable to have a tunable shock testing device that can provide

particular amplitudes.

One possible configuration is sketched below although better designs may exist. Some designconsiderations for the striking block may include the mass, the material and the velocity. Various plate

materials could be used as well. Are there predictable relationships between the shock amplitude and the

kinetic energy of the system? Is the system dependent on the materials of the two striking surfaces? The

character of the pressure wave passing through the plate could also be measured. The control valve must

be designed such that it does not restrict airflow when opened. Ear protection must be worn for all tests.

Project 21. Maximizing the Power Output of Solar Cells

Advisor: Prof. C. Radovich Difficulty: Easy to Moderate

The effectiveness of a solar cell at producing usable power is directly related to the amount of incoming

light (solar irradiance, W/m2). Unfortunately, the amount of available solar irradiance varies greatly with

geographic location and time of day. Therefore, given the expensive cost of solar cells, it is desirable to

maximize the amount of solar irradiance incident on any given solar cell ( i.e., maximize the number of

Watts per m2).

irradiance received by the solar cell and measure how each variation affects the power output. Examples

include, but are not limited to: reflectors, sun tracking and/or lenses. An optimal setup may be found using

a combination of add on devices. Are there any limits associated with the use of solar concentrators?


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Project 22. Design and Build a Pea Shooter and Measure the Projectile Velocity

Advisor: Prof. V. Eliasson Difficulty: Moderate

For this project the student(s) should:

Design, build and test a pea shooter.

Design, build and test a velocity measurement system for the pea shooter projectiles.

The pea shooter consists of a pipe divided into two parts, separated by a fast-acting valve. The rear

part, the air chamber, needs a filling valve where pressurized air can be pumped in before the shot.

Figure 1. Pea shooter: (1) air chamber, (2) fast acting valve, (3) projectile position before firing,

(4) launch tube, (5) velocity sensor, (6) catcher box.

The velocity measurement device should not interfere with the projectile itself, it has to be a non-

intrusive measurement method.

Safety restrictions:

The pipe has to be pressure rated to handle 150% of the maximum pressure intended for use.

Do NOT use a pipe made of ABS or styrene material.

There has to be a catcher box to catch the projectiles, for example a plywood box filled with jeans.

Always handle the pea shooter as if it is loaded.

Never point the pea shooter at people, animals or a non-target.

Never look into the barrel of an unverified launcher.

If the velocity measurement device will be attached to the launch tube, make sure that drilling

holes etc not does damage it.

Start with Polystyrene/Styrofoam projectiles.

The first step in the design should be to estimate the velocity of the projectile based on the diameter of

the pipe, the length of the launch tube, the weight of the projectile and the pressure and volume in the air

chamber. References with simplified models to use are listed below.

References

-gun facility for material impact studies using

low-velocity, low--774, 1989.


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Project 23. Shock Blast of Miniature Ship Models


The idea is to re-design and transform the rear part of an existing shock tube into a water shock tube.

The next step is to design a small miniature ship model, or a model of a part of a ship and blast it. Pressure

transducer(s) and high-speed photography using Schlieren visualization techniques will be used to quantifythe shock impact on the ship model.

Background: Underwater explosions generate shock waves that can hit naval vessels. In particular, if

the shock wave enters a convergent section on the ship, the shock wave will focus and extremely high

pressures can be generated at the focal region.

Figure 1. Shock tests for realistic survivability on USS Mesa Verde, 2008.

(Source:http://www.mesa-verde.navy.mil/site%20pages/pics.aspx)

The goal is to come up with appropriate laboratory experiments to quantify the shock impact, instead

of performing full scale tests.
http://www.mesa-verde.navy.mil/site%20pages/pics.aspxhttp://www.mesa-verde.navy.mil/site%20pages/pics.aspxhttp://www.mesa-verde.navy.mil/site%20pages/pics.aspxhttp://www.mesa-verde.navy.mil/site%20pages/pics.aspx


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Project 24. The Effect of Shock Waves on the Human Head


Traumatic brain injury (TBI) has been called the signature injury of the Iraq War due to the fact that

increasingly powerful so-called improvised explosive devices (IEDs) and rocket-propelled grenades are used

as weapons. Better body armor and good access to medical care has resulted in that many soldiers whoseinjuries previously would have been fatal are returning alive but with brain injury due to blast waves. Here,

we are interested in the wave propagation through a simplified model of the human head, and, in

particular, we want to find out if there are any shock focusing effects as the shock wave passes through the

model.

A sketch of the model is shown below. At first, a 2D model will be used with transparent materials in

order to allow for high-speed photography using a Schlieren visualization method. One (or two) materials

can be used to include the effect of density changes across the solk


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Project 25. Dynamics and Control of a Radio Controlled Scale Harrier Model

Advisor: Prof. P. Ronney and E. Schuster Difficulty: Moderate

Mr. Ewald Schuster, a research laboratory technician in AME, is a well-known movie set and model

airplane builder. His major personal project is a 1/6 scale Harrier jet. The turbofan engine has been built

and tested (including the ducting for vertical takeoff and landing) but the flying characteristics of thisscaled-down aircraft have not been tested. They will certainly be quite different from the full scale aircraft.

Careful design of the control system incorporating the dynamic response of the vehicle airframe and

propulsion system is needed to obtain a vehicle that will take off and land vertically as well as fly in a

straight line at high speeds. Another project might involve characterizing and tuning the propulsion system

or adding a second compressor stage, which would drastically improve the thrust to weight ratio of the

vehicle.

Project 26. Effect of Turbulence on Trichodesmium Nitrogen Fixation

Advisor: Prof. P. Ronney Difficulty: Difficult

Trichodesium is a family of marine bacteria that are responsible for a large portion of the conversion of

atmospheric nitrogen into organic nitrogen that is needed by all living organisms. The understanding of the

rates at which trichodesium convert ("fix") nitrogen is crucial to developing accurate models of the earth's

organic nitrogen balance; in fact, managing the nitrogen cycle is one of the 14 "Grand Challenges"

recommended by the U.S. National Academic of Engineering. One facet of trichodesium that has never

been characterized is the way in which turbulence in the ocean affects the formation of colonies (which are

an essential part of the trichodesmium life cycle). In this study, the effect of turbulence on colony

formation and nitrogen fixation will be studied using a Taylor-Couette cell which provides extremely well

controlled turbulent flow.

Project 27. Microscale Combustion

Advisor: Prof. P. Ronney Difficulty: Difficult

It is well known that the use of combustion processes for electrical power generation provides

enormous advantages over batteries in terms of energy storage per unit mass and in terms of power

generation per unit volume, even when the conversion efficiency in the combustion process from thermal

energy to electrical energy is taken into account. The objective of this project is to develop combustion-driven power generation devices at very small scales, typically in applications where batteries are currently

used. Currently we are studying ways to minimize or prevent flame extinction in small-scale combustors,

which is more problematic than for large-scale combustors because of higher surface area to volume ratios

for small-scale combustor and thus larger heat losses. This project entails testing the performance of

various small-scale combustors and determining optimal operating conditions.


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Project 28. Wave Generation for Artificial Surfing

Advisor: Prof. A. Fincham Difficulty: Difficult

This project is aimed at optimizing the wave generation process for man-made surf pools being

developed by the Kelly Slater Wave Company (KSWC). KSWC is pursing the perfection of man-made surfing

waves, and will be providing support for this project. They have the long-term objective of producing the

first world class artificial wave. This would require the generation of waves of consistent quality and

variable difficulty, from a man-made facility. Typically, such waves are generated by moving paddles at the

edges of water basins, and tend to be relatively small. KSWC generates their waves from the supercritical

wakes of moving hydrofoils.

This project will involve the testing of several new wave generating concepts for KSWC and will be

performed in the RRB blue water channel. The water channel is equipped with both ultrasonic wave height

sensors and lift and drag force sensors.

The supercritical (object moving faster than the wave speed) generation of these shallow water waves

has an analogy to supersonic flight where the generation/mitigation of sonic boom noise is one of the

principal challenges.

New geometry hydrofoils will be tested for their ability to produce larger swells with lower secondary

disturbance.

The figure shows a generic wave generating foil being towed along the canal.


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The following group of experiments was suggested by Prof. Stephen Davis of Northwestern University.

They involve various aspects of the dynamics of interfaces. Prof. Maxworthy will be the local advisor for

all of them. Prof. Davis can be contacted if necessary to clarify any points of difficulty. Several use the

fact that surface tension (ST, sy

temperature the ST varies and can drive a surface flow that then diffuses into the interior of the fluid. In

the literature this is usually called Marangoni Convection (called MC in what follows). A good startingreference is: Annual Review of Fluid Mechanics., v 33, pp 93-127.

Project SD 1. Measure the Temperature Coeff

Most of the following experiments require a knowledge of the variation of surface tension with

temperature. We have a Tensiometer that can measure this quantity but there is no way to carefully

control the temperature of a small (50ml) sample. Design and build such a temperature bath and use it to

r the variety of fluids to be used in the following projects.

Project SD 2. Isothermal and Non-Isothermal Droplet Spreading

When a drop of viscous fluid is dropped onto a horizontal plate (heated or not) it spreads in a

predictable way. Set up such a system and determine the spreading history for a variety of conditions, i.e.,

fluid viscosity, ST and contact angle at the solid surface and surface temperature. Ref.: Ehrhard and Davis,

1991, J. Fluid Mechs., v229, pp365-388 and v257, pp463-483. The experimental set-up in the second paper

is more sophisticated than needed for the present experiments.


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Project SD 3. Dynamic Drying of a Thin Film

A strip heater on the bottom of a shallow tank is submerged under a thin (approx. 1mm) layer of fluid.

When the heater is activated a surface flow (MC) is generated that removes fluid from the neighborhood of

the heater. For strong enough heating a dry line is formed. For various fluids determine this limit. A theory

is available against which you can compare your results. Ref.: Tan, Davis and Bankoff, 1990, Phys. Fluids, 2A,

p313. Burelbach, Bankoff and davis, 1990, Phys. Fluids, 2A, p322.

Project SD 4. Stability of a Liquid Bridge

One of the more interesting experiments proposed for the International Space Station is to refine

useful materials in a liquid bridge. The so-

both gravity and ST effects limit the length of the bridge that can be formed. It has been suggested that by

applying a temperature difference across the bridge the MC flow can stabilize the ST driven instability to

some extent. Set-up a simple experiment to study this effect. Firstly, look at the mode of break-up under

isothermal conditions then with an applied temperature difference. Ref.: Xu and Davis, 1985, J. Fluid

Mechs., v161, p1; Lowry and Steen, 1997, J. Fluid Mechs., 1997, v330, p189.


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Project SD 5. Movement of a Droplet in a Temperature Gradient

A droplet placed on a flat, horizontal surface is subject to a temperature gradient, T/x, in that

surface. Due to the MC flow generated by the ST variations the droplet moves. For a range of liquids and

surfaces with different contact angles determine the velocities as a function of the temperature gradient.

Ref.: Smith, J. Fluid Mechs., v294, p209.

Project SD 6. The Stability of a Liquid Interface in a Temperature Gradient

This is a variation on Project SD 5). A thin film is place on a metal substrate on which a T/xis applied.

The leading edge can become unstable to a wavy instability and drive a fingering instability similar to the

one seen when a layer of paint runs on a vertical surface. Study this phenomenon for a couple of different

fluids as a function of film thickness and magnitude ofT/x.


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Project SD 7. Bubble Motion in a Tube Under the Influence of a Temperature Gradient

Project SD 7A: An immiscible bubble

Under isothermal conditions a bubble in a horizontal tube will not move. However, if a temperature

gradient is applied to the tube the resultant MC flow will cause the bubble to move. Measure this velocity

as a function ofT/xas well as fluid/fluid types and bubble length.

Project SD 7B: A miscible bubble

There has been a suggestion that the interface between two miscible fluids can support an

If true then a miscible bubble should also move under the action of a T/x. Set up an

experiment to check this possibility. A negative result is perfectly acceptable. Ref. Young, Goldstein and

Block, 1959, J. Fluid Mechs., v6, p350.

Project SD 8. Classic Marangoni Convection (MC)

Classical MC is the case where a thin layer of fluid is heated from below and cooled from above.

Sometimes called Surface-Tension-Driven Rayleigh-Benard Convection. Set up such a system, as sketched

below, and determine the stability conditions. In particular study the relative importance of gravitational

versus ST driven convection by, for example, varying the layer thickness.


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Project SD 9. Droplet Motion in a Wind

A droplet sitting on a flat, horizontal plate is held in place against a lateral force by ST at the

intersection with the solid surface. Place such a bubble in a wind stream and determine at what velocity it

moves. Try to determine the force balance at this condition. One of the components of this force balance is

the drag on the droplet. It would be interesting, as a preliminary and perhaps the only investigation, to

measure the drag on a sphere and hemisphere, say, resting on the surface as a function of the relevantparameters.


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Nano/micro/meso-scale flow investigations

The following projects relate to the future development of micro-scale devices (or MEMS,

microelectromechanical systems). Due to facility availability and the purpose of the 441aL class, the current

goal is to design, manufacture, and test scaled-up meso-scale (mm or cm size) prototypes. Additional to the

meso-scale prototype, designs and simulations of micro-scale devices can be done using CoventorWare.

CoventorWare is the leading MEMS development software and 441aL students have the privilege of

accessing it. For students who are interested in microfluidic systems such as inkjet printer heads, micro

pumps, and micro valves, CoventorWare microfluidic modules have the ability of modeling and simulating

the fluid flows in micro-scale with the considerations of micro- and nano-scale fluidic effects. An example of

a micro-scale mixer is shown in the following figure to demonstrate changes of concentration along the

mixer. Details regarding CoventorWare can be found inhttp://www.coventor.com/coventorware.html .

Figure 1. Simulation of a micromixer using ConventorWare

The followings are a few suggested projects. Students are encouraged to develop the projects of their

interest that can be applied in micro/meso-scale flow investigations.
http://www.coventor.com/coventorware.htmlhttp://www.coventor.com/coventorware.htmlhttp://www.coventor.com/coventorware.htmlhttp://www.coventor.com/coventorware.html


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A. Thermal Creep Flow Application

Thermal creep flows, a rarefied gas phenomenon, can be utilized in micro/meso-scale pumping

systems. The Knudsen Compressor, a micro/meso-scale gas pump driven by thermal creep flows, has been

investigated by Prof. Muntz and Dr. Han for the past few years. A schematic illustration of a Knudsen

Compressor stage is presented in Fig. 2. A single stage is defined as the combination of: a membrane,

which consists of a parallel array of small gas flow channels; and a hot-side connector section, which has an

appropriately larger single flow channel. The rarefied flow phenomenon of thermal creep (or thermal

transpiration) occurs inside the membrane channels due to the imposition of a temperature gradient across

the thermal creep membrane. The connector is used to return the gas to its original temperature, prior to

entering the next stage. More specifically, a pressure increase across the membrane is created by the

due to the thermal creep effect. The direction

of the thermal creep flows inside the membrane channels is from cold to hot, thus left to right in Fig. 2. A

return flow, caused by the induced pressure gradient, creates a flow from the hot end to the cold end of

the membrane (right to left in Fig. 2). The maximum up-flow (defined as flows from left to right)

corresponds to a pressure change approaching zero, or a zero net up-flow can be obtained, assuming a

closed system, in which case a maximum pressure increase is present. In general, a linear temperature

decrease is also imposed along the horizontal wall of the hot-side connector section. In normal Knudsen

Compressor operations, the flow in the connector section is defined to be in the continuum regime

(Kn


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Besides all the previous work, there are still many interesting applications and variations of the

Knudsen Compressor that can be investigated and they are presented in the following projects.

Project M 1. Micro/Meso-scale Pump for Air Electrodes that Limits the Exposure of the Air Electrode to

the Atmosphere for Use in Micro Fuel Cells

Advisor: Prof. Muntz Difficulty: Moderate

Some fuel cell technologies produce energy from oxygen in the air. Oxygen (cathode reactant) diffuses

directly into the fuel cell system from atmosphere. Drying out of the air electrode or absorbing water

moisture from the humid air can adversely influence the electrode's performance. A suitably designed

micro-pump/air electrode structure that limits the exposure of the air electrode to the atmosphere could

result in extended service life making this system more attractive for many general use applications.

Figure 4. Illustration of the proposed Knudsen Compressor

The basic pump proposed here is a single stage Knudsen Compressor to provide the required air mass

flow for the fuel cell air electrodes. The possible design is shown in Fig. 4. An aerogel membrane is

sandwiched in between two thermal guards. The hot thermal guard conducts heat to one side of the

aerogel surface while the cold thermal guard keeps the other side of the aerogel surface close to ambient

temperature. Air will be drawn from the air inlet through the membrane to the air electrodes once the heat

source is on. When sufficient volume of air has been drawn into the chamber, the heat source will beturned off and the sealing valve will be activated to seal the air inlet by simple electrical switches.

The task is to design and test the Knudsen Compressor to meet the required flow rate of 17 cc/min and

maximum power consumption of 6.5 mW/cc/min by choosing the heating method and the size of the

thermal creep membrane (aerogel is suggested here). The valve system will be investigated separately.


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Project M 2. Cooling System: Waste Heat Driven Knudsen Compressor


Currently, the available cooling technologies for components in personal computers are a combination

of heat sinks and fans. However, the noise level of cooling fans is always a great concern. There are some

suggestions regarding how to reduce the noise level and many products in the market can assist you tohttp://www.endpcnoise.com/cgi-bin/e/silentpc_cooling.html ). Since

if one can use the Knudsen Compressor to draw in cold air to cool the components in personal computers

without additional energy consumption (another advantage of using Knudsen Compressor).

The task is to design and test a Knudsen Compressor that is driven by the waste heat generated by a

certain component (CPU, memory, anything you like) in a personal computer. The design concerns will

include the cooling ability and the size of the Knudsen Compressor. The testing results are expected to

demonstrate the possibility of using the Knudsen Compressor as a cooling device for components in

personal computers.

Project M 3. Alternate Heating Technique for Knudsen Compressors


-scale Knudsen Pump. A narrow

channel, as the thermal creep channel, was connected to a large channel. Along the side of the large

channel, a heating element was placed in front of but not in direct contact with the narrow channel. Steady

d in good agreement with the

theoretical free molecular predictions. However, there is no in-depth investigation for meso-scalecounterparts. The task is to design and test a meso-scale Knudsen Compressor with no direct heating on the

thermal creep channel but only with an isolated heater located outside of the membrane channel.

Ref: Journal of Microelectromechanical Systems, Vol. 14, No. 4, August 2005

Figure 5. Schematic of the micro-scale Knudsen Compressor investigated by Isolated Heating Element
http://www.endpcnoise.com/cgi-bin/e/silentpc_cooling.htmlhttp://www.endpcnoise.com/cgi-bin/e/silentpc_cooling.htmlhttp://www.endpcnoise.com/cgi-bin/e/silentpc_cooling.htmlhttp://www.endpcnoise.com/cgi-bin/e/silentpc_cooling.html


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Project M 4. Thermal Creep Flows Through Nano-Scale Sized Channels


Based on the rarefied flow phenomenon of thermal creep (or thermal transpiration), the Knudsen

Compressor is an unconventional micro/meso-scale compressor or pump. At higher pressures (> 1 atm), to

maintain membrane channel Knudsen numbers in the transitional regime (Kn ~ 1), the correspondingmembrane channel size needs to be less than about 50 nm. More specifically, at 10 atm, the membrane

channel size should be as small as 5 nm to provide the most efficient Knudsen Compressor operation. For

thermal creep flows through channels less than 5 nm, phenomena due to intense surface/gas interactions

could happen. Experimental studies using porous glass membranes with 4 nm diameter membrane

channels will provide more understandings of the surface/gas interaction.

Figure 6. Schematic of the Knudsen Compressor with a porous glass membrane

Project M 5. Thermal Creep Flows Through a Glass Microsphere Bed


Self-assembled glass microsphere beds can be alternative transpiration membranes for application in a

Knudsen Compressor. Previous design is shown in Fig.7 but the performance of this design is significantly

compromised due to poor thermal contact. The main task of this project is to update and optimize the

design and perform experiments to test a Knudsen Compressor stage using glass microsphere membranes.

Figure 7. Previously studied Knudsen Compressor using a Glass Microsphere

Bed as the thermal transpiration membrane


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B. Electrostatic Actuation

Using electrostatic energy to actuate a MEMS mechanical device is the most common approach.

Electrostatic charges arise from buildup or deficit of free electrons in a material. An electrically charged

material can exert an attractive force on oppositely charged objects or a repulsive force on similarly

charged ones. Applying a voltage, V, across the two electrodes shown in Fig. 6, the electrostatic potential

energy stored between them is

Here r is the relative permittivity and o is the permittivity in vacuum. and represent the real

dimensions in the X and Y directions respectively. represents the real dimension of the separation

between the electrodes, which is along the Z direction.

Figure 8. Illustration of the electrostatic field

Therefore, the electrostatic force introduced by the electrodes is,


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For a pair of electrodes with width = in the X direction and length = in the Y direction, and the

separation = in the Z direction, the electrostatic force in each direction is,

There are many other applications of electrostatic actuators and here are potential projects for

students who are interested in flow devices actuated by electrostatic forces.

Project M 6. Diaphragm Pumps


The first practically successful micropump shown in Fig. 9 by Zengerle et al. was accomplished using

electrostatic actuation. The actuator is made from two silicon chips that embody the flexible pump

diaphragm and a rigid counter electrode in a capacitor-like configuration. Applying high voltage to the

capacitor electrodes causes electrostatic attraction of the pump diaphragm which in extreme becomes fully

attached to the counter electrode. After discharge of the capacitor the pump diaphragm relaxes to its rest

position. The task of the project is to design and test a meso-scale diaphragm pump, which may or may not

be similar to Fig. 9. The design aspects include the size of the electrodes, the selection of the diaphragm,

the flow rate of the pump. The testing results will include the energy consumption, and the flow rate of the

pump.

Figure 9. Illustration of Zengerl

Ref: Sensors and Actuators, 77 (1999(, 223-228.


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C. Other Meso-scale Devices

Project M 7. Electroosmotic Micropumps


Electroosmotic (EO) pumping uses the surface charge that spontaneously develops when a liquid comes

in contact with a solid. Bulk liquid counter-ions shield this surface charge, completing the so-called

electrical double layer (EDL). Some portion of the counter-ions in the liquid phase of the EDL can be set into

motion by applying an electric field parallel to the wall (see Fig. 11). The mobile ions drag bulk liquid in the

direction of the electric force. Bulk flow is therefore induced in the direction of the electric field. The key

parameters that dictate the performance of EO pumps are (1) the magnitude of the applied electric field

and applied voltage, (2) the cross-sectional dimensions of the structure in which flow is generated, (3) the

surface charge density of the solid surface that is in contact with the working liquid and (4) ion density and

fluid and operating conditions. The testing results will include the flow rates of the bulk flow, the applied

voltages, and types of the working fluids and the sizes of the capillary channels.

Figure 11. A demonstration of the EO pump. An externally applied electric field causes motion of counter ions that

shield a negative wall charge. Ion drag forces the flow against a pressure gradient.

Ref. Probstein R F, (1994) Physicochemical Hydrodynamics, Wiley.

D J Laser and J G Santiago, J. Micromech. Microeng. 14 (2004) R35R64

ame 441al handout - fall 2010

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