multidisciplinary undergraduate research in computational ......jul 13, 2012  · modeling...

Padmanabhan Seshaiyer

Professor, Mathematical Sciences

Director, COMPLETE Center

George Mason University

Email: pseshaiy@gmu.edu

Multidisciplinary Undergraduate Research in Computational Mathematics and Nonlinear Dynamics of

Biological, Bio-inspired and Engineering Systems

Best Practices for Introducing Undergraduate Students to

Computational and Interdisciplinary Research

SIAM Annual Meeting

July 13, 2012

UG Students as change agents

Padmanabhan Seshaiyer

George Mason University

University & K-12 STEM Collaboration

Sarah M. Venuti (Undergraduate Student)Avis Foster (Undergraduate Student)Kris Kappmeyer (K-12 Teacher)Alicia Hamar (High School Student)Stephanie Alley (Undergraduate Student)Andrew Samuelson (Graduate Student)

Padmanabhan Seshaiyer

George Mason University

BloodArterial Wall

CSF

Transforming Practice Through Undergraduate Researchers, P. Seshaiyer, Council on undergraduate research Quarterly, Fall 2012.

REU: COMPUTATIONAL MATHEMATICS AND NONLINEAR DYNAMICS OF BIOLOGICAL, BIO-

INSPIRED AND ENGINEERING SYSTEMS

• Summers 2012-2013, 2011-2012, 2009-2010 and 2007-2008

• Stipend $3375; Free on-campus housing and meals; Travel allowance up to $550 and more!and more!

• Supports 12 students and 2 K-12 teachers each year

• http://math.gmu.edu/reu

Sample Research Topics

Modeling using deterministic and stochastic differential equations

Computational biology, biomechanics and neuroscience

Mathematics of Materials

Nonlinear dynamics and Micro Air Vehicles

Selected Quotes from participants

"It has inspired me to push the limits, to keep asking questions and keep believing we can solve any problem.”

“I have been exposed to many applications that I

Padmanabhan Seshaiyer

George Mason University

“I have been exposed to many applications that I did not know existed before.”

“I used to think doing research in math was purely proof based. Now I see that research in math has endless possibilities.”

“The research program has greatly helped me to answer the question that my students always seem to have…when am I ever going to use this?”

Nature of Student Activities

• Lecture Series

• Mentoring Club

• Guest Colloquium

• REU Participant Seminars

Padmanabhan Seshaiyer

George Mason University

• REU Participant Seminars

• Computational Laboratory

• Scientific and Social Tours

• Lesson Study

A Computational Model for Batten Behavior in Micro Air VehiclesSyeda Khadija F. Zaidi (University of Maryland, College Park)

Applying Numerical Methods to Fluid Structure Interactions in Biological SystemsCourtney Chancellor (Southern Methodist University)

Ordinary Differential Equations in Green Oxidation Processes

Sample Computational Mathematics Projects

Padmanabhan Seshaiyer

George Mason University

Ordinary Differential Equations in Green Oxidation ProcessesAngela Dapolite (Clarkson University)

Viscoelastic Modeling of Biological Tissue in an Idealized Cerebral AneurysmKris Kappmeyer (H-B Woodlawn Highschool)

Modeling Evaporation from the pre-lens tear film over a contact lensAmber Xu (Carnegie Mellon University)

Optimization of an Antenna Structure for a Photovoltaic DeviceEmily Forney (Clemson University)

Analysis of Spherical Inflation Models for Intracranial Saccular Aneurysm Elasto-dynamicsJames Halsall (Farmingdale State College, New York)

Multidisciplinary Research in Mathematics

• As concluded by the National Research Council: Undergraduate education will not change in a permanent way through the efforts of “Lone Rangers.” Change requires ongoing interaction among communities of people and institutions that will reinforce and drive reform.

Padmanabhan Seshaiyer

George Mason University

reform.

• Research that happens across traditional mathematics and at the edges of traditional disciplines.

• Here is the problem,

find the mathematics to solve it!

HumanHealth

BasicScientificResearch

Energy &Natural resourcesMultidisciplinary

Research

Padmanabhan Seshaiyer

George Mason University

Health

Defense &National Security

Sustainabilityof the

Environment

ResearchImpactAreas

ComputationalBiomechanics

MathematicalBiology

MaterialsModeling

NonlinearDynamics

StochasticDifferential Porous

Mathematics in someMultidisciplinary

Padmanabhan Seshaiyer

George Mason University

Differential Equations

FluidDynamics

Fluid-StructureInteraction

ControlTheory

Optimization

PorousMedia

MultidisciplinaryResearch Topics

Saccular Aneurysms: Rupture

Padmanabhan Seshaiyer

George Mason University

Identification of Rupture Potential

Characterization of material properties

Padmanabhan Seshaiyer

George Mason University

Contact constraints

Elasto-dynamics

Coupled flow-structure interaction

Bifurcating Artery-Aneurysm Model

Padmanabhan Seshaiyer

George Mason University

MAV: Membrane Wing Deflection

Padmanabhan Seshaiyer

George Mason University

Experimental Challenges in MAV Design

Small size

High surface-to-volume ratio

Constrained weight and volume limitations

Padmanabhan Seshaiyer

George Mason University

Constrained weight and volume limitations

Low Reynolds number regime

Low aspect ratio fixed to rotary to flapping wings

Longer flight time

Better range-payload performance

Computational Challenges in MAV Design

Structural Dynamics

Fluid Dynamics

FSI

Padmanabhan Seshaiyer

George Mason University

Guidance & Control

Propulsion &Power

Beam-Fluid Interaction

Padmanabhan Seshaiyer

George Mason University

What makes these problems interesting?

Fully three-dimensional

Heterogeneous/Homogeneous

Anisotropic/Isotropic

Padmanabhan Seshaiyer

George Mason University

Anisotropic/Isotropic

Compressible/Incompressible

Non-linearity/Linear

Large/Small Deformations

Dynamic/Static

And more ………

Key Steps in Mechanics

Kinematics

Forces

Balance Relations

Padmanabhan Seshaiyer

George Mason University

Balance Relations

Constitutive Formulation

Boundary/Initial Conditions

Boundary/Initial Value Problem

Solution Methodology

Physical System

Padmanabhan Seshaiyer

George Mason University

Mathematical Model

Predator-Prey Problem

XYYdt

dY= 1α

2α__

dX

Padmanabhan Seshaiyer

George Mason University

Kteyty

yKdt

dyty

dt

dy

0)(

)(

=⇒

=⇒α3

α XY4α__ +

Y(0) = Y0

X(0) = X0

Xdt

dX=

Displacement of a Linear Elastic Bar

X=a X=b

f(x)

u(x)

Padmanabhan Seshaiyer

George Mason University

)(xfdx

d

dx

duK

dx

du

−=

=⇒

σ

σασ

0)(

0)(

)(

=

=

=

−

bu

au

xfdx

duK

dx

d

Solution Methodology

Physical System

Padmanabhan Seshaiyer

George Mason University

Mathematical Model

Analytical Solution

Compare

Finding an Analytical Solution

)(=

− xf

dx

duK

dx

dXYY

dt

dY= 1α

2α__

BVP IVP

Padmanabhan Seshaiyer

George Mason University

0)(

0)(

=

=

bu

au

dxdx

3α

dt

XY4α__ +

Y(0) = Y0

X(0) = X0

Xdt

dX=

Solution Methodology

Physical System

Mathematical Model

Padmanabhan Seshaiyer

George Mason University

Mathematical Model

Numerical SolutionAnalytical Solution

Experimental DataCompare Compare

Compare

BVP or IVP

Finite Element Methods

Finite Difference Methods

Shooting Methods

RungeKutta

Methods

….............

Experimental Data

Padmanabhan Seshaiyer

George Mason University

Solution to a System of Equations

Direct Methods

Indirect Methods

Error Analysis

Solution to BVP/IVP

Fluid

Flow-structure interaction (FSI)

Γ

Solid FluidSolid

Padmanabhan Seshaiyer

George Mason University

0.

).(

),0(:

=∇

=∇+∇+∆−∂

∂

×Ω

u

fpuuut

u

TFluid

f

f

νρr

Γ

])([5.0~

~2)~(~

~.

),0(:

2

2

T

s

s

ww

tr

bt

w

TSolid

∇+∇=

+=

=∇−∂

∂

×Ω

ε

εµελσ

σρ

Γ

Beam – Flow Interaction

Modeling Arterial Wall-Flow Interaction

BloodArterial Wall

CSF

Padmanabhan Seshaiyer

George Mason University

MathematicalModel

Modeling, Analysis and Computation of Fluid Structure Interaction Models for Biological SystemsS. Minerva Venuti and P. Seshaiyer (Mentor), SIAM Undergraduate Research Online (2010)

Inner wall Outer wall

Arterial Wall

km Spinal Fluid ∞

),( txu

Blood

One-dimensional Model

Padmanabhan Seshaiyer

George Mason University

x-direction

)sin(0

tXX b ω=

rho 1000 kg/m 3

density of spinal fluid

mu 0 Stokes viscosity of spinal fluidc 1500 m/s velocity of spinal fluidm 1.0 kg mass of the arterial walla 0.01 m2 area of the outer arterial wallk 8000 N/m spring constant

omega 1 rad/s frequency of heart beatX0 0.01 amplitude of heart beatXb displacement imposed by the pressure

exerted against the arterial wall by the blood

Coupled FSI System

2

22

2

2

x

uc

t

u

∂

∂=

∂

∂Lx <<0

Padmanabhan Seshaiyer

George Mason University

0for 0)sin(),0(),0( 0

2 ==−++∂

∂−

••

xtkXtkutumax

uc ωρ

LxtLx

uctLu =

∂

∂−=

•

for ),(),(

=)0,(xu 0)0,( =•

xu

Analytical Solution

tDtCBeAetutrtr

sincos),0( 21 +++=

2

)/(4)/(/2

1

mkmcamcar

−−−=

ρρ=2r 2

)/(4)/(/2

mkmcamca −+−

ρρ,

Padmanabhan Seshaiyer

George Mason University

,)(*)(

)/(22

121

0

ω

ω

+−=

rrr

XmkA ,

)(*)(

)/(22

212

0

ω

ω

+−=

rrr

XmkB

222422222

0

)/(2

)/(

kmkmmca

mcaXmkC

+−+−=

ωωωρ

ρωand

222422222

2

0

)/(2

)()/(

kmkmmca

kmmXmkD

+−+

−−=

ωωωρ

ωω

.

Displacement at x=0

Padmanabhan Seshaiyer

George Mason University

Variations on parameter k - stiffness

K=4000K=4000 K=16000

K=8000 K=32000

Variations of rho - density

Rho = 500 Rho = 2000

Rho = 1000 Rho = 4000

Rho = 500 Rho = 2000

How does new research problems evolve?

uF spring

Artery wall

Padmanabhan Seshaiyer

George Mason University

γ

fluid

F damping

F blood = kX0cosωt

mutt(0,t)

Fx

v

x

P

x

vv

t

v=

∂

∂+

∂

∂+

∂

∂+

∂

∂2

2

µρρ

What type of transformative research and training can one do?

Modify Key Assumptions

Build Realistic Geometry

Padmanabhan Seshaiyer

George Mason University

Optimize Mathematical Techniques

Enhance Mathematical Software

Match Experimental Data

Refine Mathematical Model

Perform Parameter Estimation Studies

My Contacts!

Padmanabhan Seshaiyer

Mathematical SciencesMathematical Sciences

George Mason University

Email: pseshaiy@gmu.edu

Web: http://math.gmu.edu/~pseshaiy

http://math.gmu.edu/~pseshaiy/outreach.html