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J. Energy Power Sources Vol. 1, No. 4, 2014, pp. 198-216 Received: August 3, 2014, Published: October 30, 2014

Journal of Energy and Power Sources

www.ethanpublishing.com

The New Method of Converting the Kinetic Energy of the

Flow of a Fluid Medium in Electrical Energy—Part 1

Serhii Honcharenko

Kimo-Business, Kiev, Ukraine

Corresponding author: Serhii Honcharenko ([email protected])

Abstract: The article is devoted to a fundamentally new source of renewable energy. This source of renewable energy really exists in the world. This source originally used by all aquatic beings, and also by those which live in the ground. In science and techniques this physical phenomenon are known as self-oscillations of the flutter type. This phenomenon is considered like harmful and dangerous, and in a very short period of time (a few seconds) it leads to sharp growth of dynamic loads of technical object (plane, heat-exchange apparatus, building construction, etc.) and even to the destruction of this object. Thus the energy of self-oscillations of the flutter type is very big. The purpose of this paper are learn to get and control this energy. The article presents the design of a device for converting kinetic energy of stream into electrical energy and results of tests of this device in the stream of air and in water. The article also presents an original method of testing in the air stream. The methodology of the mooring trials of the laboratory device is similar to the methodology of mooring trials of the usual ships. Results of tests confirmed a possibility to get and control the energy of self-oscillations of the flutter type. One and the same device work equally effectively in the air flow and water. The device has no overturning moment. This method can be also successfully used by humanity for producing energy without harming nature. Key words: New source of renewable energy, kinetic energy.

1. Introduction

Ability of the fish to swim in ocean depths and the

bird to fly in heavenly spaces has been a mystery for

humanity from time immemorial. People tried to solve

a secret of movements of fish and birds, tried to

reproduce the movements of fish to swim like a fish. It

seems like everything is simple: Move your tail and

fins, or flap your wings and movement is provided.

There was worked out a base style of high-speed

swimming called “Dolphin”, however, the swimmers

were got tired very quickly with it. Long since people

dreamt to fly as a bird, tried to increase the area of arms

and to repeat a flap of wings, but such attempts always

ended with the fall of the braves. Later, with the

development of technology, people began to open up

ocean depths and heavenly spaces with the help of

mechanisms (sea and river ships, air and space

vehicles). Having a great speed and range of motion

people began to move even faster than the water and air

beings. Besides, the man-made mechanisms can

transport extra load over long distances. However, any

slight increase in the speed in man-made mechanisms

required a substantial growth of expenditure of primary

energy (chemical, electric, mechanical, etc.).

Development of the human became conflict with the

Nature laws: The higher is the level of development,

the more natural resources people consume for

satisfaction of their needs. But these resources are not

endless, in a very short time humanity will face a

question: Where to get the energy?

And the people again draw their attention to the fish

and birds, and again the question arises: At the expense

of what these beings are moving, where do they get the

energy for their movement?

2. Renewable Energy

Renewable or regenerative energy is energy of

The New Method of Converting the Kinetic Energy of the Flow of a Fluid Medium in Electrical Energy—Part 1

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sources which are inexhaustible by people’s standards.

The main principle of renewable energy use is its

extraction from processes continuously happening in

the environment and further provision for technical

application. The most known renewable energy

sources are wind, river flow, sea flow, sea waves,

breaking waves, high and low tides. Despite of

different reasons of generation, all the renewable

energy sources specified above, including the main

renewable energy source—solar radiation, have the

common characteristic: They all constitute a fluid flow,

they all are in constant movement, and they all have

kinetic energy. Kinetic energy of air flows is converted

into electric energy with the help of propeller-type

converters. At the present time there are no effective

converters of water flows kinetic energy into electric

energy. Also, there is no converters kinetic energy of

the solar flux to electrical energy. Growing needs in

electric energy and low efficiency of existing plants

used for generation of electric energy from renewable

energy sources make inventors to look for new

technologies and to develop new devices for obtaining

of ecologically clean energy. In particular, this is of

current importance for Marine Renewable Energy

Sources, such as wind, tides, waves and sea currents.

Propeller-type energy converters have high loss of

kinetic energy due to the flow turbulization (up to 85 %)

and related ecological problems. Oscillation-type

converters do not have these disadvantages. Besides

that, if certain conditions are created during the

oscillation process, it is possible to obtain significant

amount of additional energy (condition of resonance [1]

and condition of self-oscillations of “flutter” type [2]).

3. Analysis of Existing Devices of the Oscillatory Type for the Conversion of Kinetic Energy of a Flow into Electrical Energy

The authors of works [3-4] proposed a number of

devices for the conversion of the kinetic energy of a

flow into electrical energy with the help of resonance

oscillations. In all of these devices, the authors try to

increase the efficiency of conversion of kinetic energy

of a fluid medium flow at the expense of the

aerodynamic lifting force of the flow and increasing the

amplitude of oscillations. However, the loses of energy

to “idling” and changing the direction of working items

to return them to previous positions bring the efficiency

of similar devices to zero.

The authors of works [5-8] proposed a number of

devices for the conversion of the kinetic energy of a

flow into electrical energy also with the help of

resonance oscillations, but with a larger degree of

freedom for fluctuating working items. They called this

process of transformation of the energy of a flow with

the help of this phenomenon “flutter”. In these papers,

the authors made the amplitude of oscillations minimal,

with the imposition of the mechanical restrictions on

the fluctuations of the working items and try to get a

gain in the transformation of the energy flow only by

giving the fluctuating parts additional degrees of

freedom. The oscillations that are obtained are chaotic,

uncontrollable and require additional energy for extra

stimulation. Therefore, the effectiveness of such

devices is also close to zero.

The authors [9-11] in their works, tried to get away

from “pure” resonance, intuitively making an attempt

to get closer to flatter fluctuations. However, they

followed requirements for designing aircrafts or turbo

machines, so they introduced restrictions on

mechanical damping into the structure of fluctuating

working items. As a result, the authors of these works

did not use any resonance or flutter. Therefore, the

efficiency of similar devices is also close to zero.

4. The Main Hypotheses

In 1920, the Austrian scientist Franz Wels, who

conducted the research into the mechanism of fish tail

movements, has concluded that the local movement of

the fish produces by curvature of the spine. The

curvature of the spine is provoked by the additional

reductions of related muscle fibers, which cause the


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bends of the fish body, always starting with the head,

moving on to the tail in the form of wave-like

fluctuations and again starting with the head. Moreover,

these wave-like fluctuations occur in the plane

perpendicular (or close to perpendicular) to the

direction of the fish movement. The movements of

birds and amphibians have the similar cause. On the

basis of these studies Franz Wels constructed and in

1921 patented the device [12], created not only to

reproduce the fish movement, but also to carry out

useful work by displacing a flow of water. In his work,

he suggested that this device can convert mechanical

energy of muscular strength or chemical energy of fuel

combustion engine into the useful work liquid

transferring, and perform the reverse conversion of the

kinetic energy of the water flow into the mechanical

energy of the motor shaft rotation as well. However,

the idea of transformation of energy of the liquid flow

into the useful work has not got the confirmation and

the efficiency of work of the device in the form of a

pump for pumping the liquid was so small, that there

was no further development. The author of the idea

tried to reproduce mechanically the kinematics of the

fish movements with the help of usual crank gear and

crank-slide mechanism without deep understanding of

the physical nature of these movements.

The author hoped to transfer the force of the flow

impact to the element placed in the flow which has the

ability to simulate the fish movements, and then,

through the slider to the piston engine power. But at the

same time the forces of mechanical dampening of the

device, were so great, that there were no movements of

the piston.

In 1936, the British zoologist professor James Gray

made the calculation of power, developed by the

dolphin muscles at a speed of V = 10 m/s (36 km/h) and

found out a fantastic paradox: Dolphin could not swim

with such speed, so as there is the lack of the

developing capacity, it is 7 times less than it is needed

[13]. This nonsense became called in science as “the

Gray’s paradox”. But the author of the calculation has

based on the fact that the boundary layer of liquid,

flowing a body of a swimming dolphin, takes turbulent

(screw) character, and this increases the friction

between the body and the water. Such an assumption

would be quite legitimate if we were talking about the

flowing the rigid body the same size and shape like a

dolphin. But in this case, the body is alive, flexible, and

J. Gray suggested that the explanation of the paradox is

possible if the flowing has a laminar (inkjet, calm)

character, in this case the friction reduces essentially.

In other words, a swimming dolphin has a kind of

mechanism for laminarization boundary layer of the

liquid.

There was created a whole direction in hydrobionics

when scientists were trying to find this mechanism or

to deny J. Gray’s calculations. Because of the rapid

growth of interest to bionics in the early 60’s the

scientists were began to pay a special attention to the

swimming of dolphins. According to the publications

the studies in this area were conducted mainly in Great

Britain, USA and USSR [14].

Many years the searches of the dolphin’s speed

secret were conducted mainly in the field of studying of

the structure and various properties of dolphin’s

integument: There was a view of creation of an

artificial covering for sea ships which would have an

ability of an integument to damp the fluctuations of the

boundary layer. However till now there are no

convincing proofs which were experimentally

confirmed that it’s only in the skin. Here it is

appropriate to notice that the most high-speed fishes of

the world ocean, such as tuna, marlins, swordfish,

bodies of these fishes are covered mostly with a big,

tough scales, and to talk about some of damping

properties of such coverage doesn’t make any sense,

and the speed of them under the water reaches 100

km/hour.

Meanwhile J. Gray in the same work suggested that

the boundary layer laminarization mechanism can be

connected with the presence of so-called negative

gradient of dynamic fluid pressure along the body of


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the animal, due to the active motion of the body like the

dolphins, as well as the fish. Simply speaking, the

nature of the movements of a floating body reduces the

pressure of the fluid from head to tail, and this reduces

the degree of turbulence. However, so far no one has

described theoretically the mechanism of the dolphin’s

movement, or, moreover, has obtained experimentally

proofs (effects) connected with the reproduction of the

kinematics of dolphin’s.

5. Self-Oscillations of the “Flutter” Type

The Scheme of the wave-like motion of the fish’s

body, presented in the work [12], resembles the scheme

of the single cylinder movement in a longitudinal flow

of the liquid at high flow rates, what leads to loss of

cylinder steadiness and the emergence of

bending-twisting flutter. The dynamics of

single-cylinder in a longitudinal flow of liquid is

studied in sufficient detail [15]. It is well established

that for small flow rates cylinders make a small random

oscillations raised by random resistance of averaged

flow; the influence of the averaged flow has an impact

on the appearance of a hydrodynamic damping and

reduction of the cylinder own frequency. However, at

relatively high flow velocities, first the system loses its

steadiness as a result of static buckling (the

phenomenon of “divergence”), and then there is a

“flutter” in it.

The concept of self-oscillations is usually applied to

oscillating objects that can take energy from a fluid

medium (air, water) while maintaining continuous

fluctuations. The process of self-oscillations is called

“flutter” when the energy is taken from a uniform flow.

The concept of “flutter” is usually applied to the wings

of aircrafts and the blades of turbo machines. Later this

name was used while researching pipe arrays of heat

exchangers.

All known sources of scientific and technical

information describe the phenomenon of “flutter” as

harmful and dangerous, which lead to the appearance

of dynamic voltage in aircrafts and heat exchangers [2,

15-17], which can be destructive. The authors of these

works do not even consider the possibility of using the

additional energy which appears during the flutter for

electrical energy reception.

Among the numerous types of vibrations and

fluctuations to which aircrafts are exposed in aviation,

“flutter” is considered as the most dangerous. The

danger lies in the fact that the intensive oscillations

provoke arising dynamic voltage in aircraft

constructions which can quickly (sometimes within a

few seconds) destroy aircraft, destroying it during the

flight [16]. This shows us that there can be a lot of

energy that is being wasted.

6. UAI (Unsteady Aerodynamic Influence)

The main types of the flutter of oscillating objects

in the flow of a fluid medium with subsonic flow are

stall flutter, lattice flutter and bending-torsion flutter

[17].

Theoretically the conditions of formation and

analysis of bending-torsion flutter of a single wing

(profile) are described in the paper [2]. If there were

only bending or only torsional oscillations, it would

abate because of aero damping (as well as mechanical

damping). The emergences of joint bending-torsional

oscillations radically change the picture. The matter of

the fact is that bending as well as torsional oscillations

of the profile will cause the appearance of unsteady

aerodynamic forces and moments (UAI (Unsteady

Aerodynamic Influence)), work of which can be both

positive and negative depending on the angle of phase

shift between bending and torsion oscillations. If

driven and dedicated energy are balancing, there are

persistent harmonic oscillations. So as the aerodynamic

forces and moments depend on the speed of the main

flow, the balance of energies will come at a certain

speed, what is called critical. If the speed exceeds a

critical, it should be observed oscillations with

increasing amplitude.

The most famous and used in technique is the lattice

flutter of turbomachine’s blades, when the blade’s


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array makes flutter oscillations in the composition of a

vibrating grate.

In the work [17] is said that the most important,

complex and diverse of all of the factors that affect the

nature and intensity of oscillations of turbomachine’s

blades are non-stationary aerodynamic influence (UAI),

arising from the oscillations of the blades in a flow.

UAI on a blade of vibrating grate of a turbomachine is

determined by the total aerodynamic influence on this

blade at its oscillations in the flow and the additional

impact caused by the oscillations of the other blades of

the grate, and transmitted through the flow. The

emergence of this impact is explaining by the fact that

when the blades are oscillating in the flow takes place a

periodic change of instantaneous values of angles of

attack and velocities of the flow-on relative to

indicators of non- forced flow by flow-on, as well as

the aerodynamic interaction of vibrating blade of a

grating, contributing additional disturbances in the

flow and changing the regime of flow-on conditions.

Thereby, UAI on one or another blade of the grating is

determined not only by its own oscillations, but also by

oscillations of other blades, which are performed with

different phase shift.

In other words, to a variable impact, caused by the

forced oscillations of the most visible blade and what is

under the opposite phase with its speed, there are added

a changing be the time impacts generated by

oscillations of the other blades of the grating, as a result

of its variable speed and changing of its situation in the

space. Under certain conditions (what are depending

not only from the shift of phases of the blade’s

oscillations), it may be that the additional impact will

change its direction for one reason or another, peculiar

turbomashines. Unsteady aerodynamic force (moment),

forced by oscillations of the blade, will change its sign,

which means it will work in phase with the speed of

the blade’s movement. Depending on the parameters

defining the oscillatory process, there are cases, when

the direction of the examined UAI coincides with the

direction of oscillation of the blade. Then, these

Influences make the positive work. If by this the

positive work of UAI in absolute value exceeds

always negative work of forces of mechanical

damping, it would be self-oscillations of blades type

flutter. In fact when flutter aerodynamic damping

changes sign, and the combined damping take

negative values. The appearance of the flutter of the

blades is characterized by a loss of dynamic stability

of its forced oscillations.

7. The Conversion of Kinetic Energy of a Fluid Medium Flow into Electrical Energy

Usually to start any study of any phenomena is

reasonable from a simple, moving to a more complex.

In practice, however, there is no information about

getting the flutter of a single profile (wing or blades),

oscillating in the flow of a fluid medium, regardless

from a flow speed.

That is why, to obtain practical results in the study of

the mechanism of getting an additional energy during

the movement of a dolphin was decided to start the

research of bending-torsion flutter of a single working

element, with the possibility to perform

bending-torsion oscillations in the composition of the

array of such working elements, when unsteady

aerodynamic influence (the forces and moments) arise

not only from the interaction of oscillating studying

working element with the flow of a fluid medium, but

also caused by the influence of one working element to

the next working element in the composition of one

studied array of working element. In this case, each

analyzed working element, included in the composition

of the studied array, must have a possibility to perform

bending-torsion oscillations, which is characterize the

flutter of a single profile.

For the conversion of kinetic energy of a fluid

medium flow into electrical energy, a device was

produced that used the kinematics of movement of

working items similar to the kinematics of movement

of a dolphin. This device combines all the best features

of examples that have the phenomena of “resonance”


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[1] and “flutter” [2, 17] for the conversion of kinetic

energy of a flow into electrical energy. The fluctuations

of working items occur at certain frequencies, which

are equal to their own frequencies. There are no

restrictions on increasing the amplitudes of the

oscillations.

According to a theoretical substantiation [2] the

bending-torsion flutter occur during interaction of

working item that performs bending-torsion

oscillations with the flow of air. Therefore, there are

unsteady aerodynamic (or hydrodynamic) forces and

moments (UАI), the total value of which (РUAI) can be

the same (when creating certain conditions) as the

direction of movement of working item. In this case the

work of the UAI is positive.

The positive work of UAI of every working item

consists of the impact of a flow and of neighboring

working items. The device makes it possible to

reproduce and manage self-oscillations of the flutter

type.

The conversion of kinetic energy of a flow into

electrical energy is caused due to the additional energy.

This additional energy appears as a result of positive

work of Unsteady Aerodynamic (or hydrodynamic)

Influences [2, 17].

8. The Design of the Single Module Device

To conduct the research there was designed and

manufactured a device. Working item of the device

could do harmonic bending-torsion oscillations in the

form of reciprocating and rotational movements.

Working items are made in the form of a rectangular

shaped thin plate. Rotary and reciprocating movements

of working items were made with the help of a group of

crank-rods, which were fixed on a stationary base in the

form of the single module device. A longitudinal view

of this device with one working item and a view of the

device from the position working item are sketched in

Figs. 1-2.

The device contains working item 1, which can be

placed in a fluid medium flow 2. Working item 1 is fixed

Fig. 1 The design of the module—Side view.

Fig. 2 The design of the module—Front view.

at the angle of 90 degrees relative to connecting rod 3.

Connecting rod 3 and slider 5 have a swing joint with

axis 6. Geometrical axis 6 is located in the plane of

working item 1. Slider 5 can make reciprocating

movement on guide 7. Guide 7 is fixed on stationary

base 4. The other end of connecting rod 3 has a swing

joint with crank 8. Crank 8 has also a swing joint with

shaft 9, which is installed on stationary base 4. The

other end of shaft 9 is designed for transmitting the


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energy of rotation of crank 8 to the device for power

reception (is not shown in figure). The amplitude of the

reciprocating movements of working items 1 depends

on the geometrical parameters of crank 8. The length of

one forward stroke of the slider will be equal to two

lengths of the crank.

Angle “L” is the angle between the plane of working

item 1 and the direction of flow movement 2. The

design of the device gives an opportunity to set an

angle of phase shifts between rotating and

reciprocating movements of working items 1 that is

required for launching the device and its effective

work. Working item 1 is immersed into fluid medium

flow 2.

9. The Interaction of the Single Module Device with a Fluid Medium Flow—The Theoretical Suppositions

The crank-and-rod mechanism with a working item

is a module, which is located on a stationary base. The

scheme of interaction of the single module device

with a fluid medium flow is sketched in Fig. 3. As a

result of this interaction, there is a conversion of

kinetic energy of a fluid medium flow into effective

work.

Fig. 3 The theoretical scheme of interaction of a single device with the flow of a fluid medium.

Key for schemes:

1: Working item;

2: Fluid medium flow;

P: Force of the flow effect on the lateral surface of the

working item which is perpendicular to reciprocating

movement of the working item;

Pn: Normal component of the force of flow effect “P”

on the lateral surface of the working item which

coincides with the direction of the reciprocating


Ps: Resulting component of force “P” which is

perpendicular to the lateral surface of the working

item;

РUAI: Total UAI of unsteady aerodynamic forces and

moments;

UAI: Unsteady Aerodynamic (or hydrodynamic)

Influences;

L: Angle of phase shift between movement and force

P;

A: Reference point;

B: Phase shift for 90 degrees relative to the reference

point;

C: Phase shift for 180 degrees relative to the

reference point;

D: Phase shift for 270 degrees relative to the

reference point.

The directions of the reciprocating movements of

working items 1, occurring due to the effect of flow 2

and the total UAI effect on the working items, are

shown by arrows.

In the work [1], formula 42 shows that if the force

acts in the direction of movement, the maximum work

of the cycle of fluctuations will occur during phase

shifts between movement and power of 90 degrees. W = π × A × P × sinα (1)

where W is the work produced by perturbation force

for one cycle in the process of steady-state forced

oscillations; π is Dimensionless mathematical constant,

which expresses the ratio of length of circumference to

the length of its diameter and equal to 3.14;

A—Amplitude of oscillations; P—Perturbation force;

L—Angle of phase shift between movement and


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strength.

Therefore, in the device the reciprocating movement

of working item should be arranged perpendicularly to

the direction of fluid medium flow. In this case power

“Pn” coincides with the movement of the working item,

and “Ps” is perpendicular to the lateral surface of

working item.

At the same time working item performs harmonic

rotational movement around the axis of its establishment.

Angle of attack “L” (the angle between the lateral

surface of the working item and the direction of flow

movement) will vary in each moment of time, reaching

its peak in the middle of reciprocating movement and

taking zero value when changing the direction of

reciprocating movement of the working item.

In this construction, the total UAI coincides with the

direction of working item movement. Working item

has the ability to perform rotary and reciprocating

movements with constant amplitudes. The phase shift

between the strength of the flow impact and

reciprocating movement of working item is equal to 90

degrees.

During implementation of this scheme of

reciprocating and rotary movement of working item in

a fluid medium flow, work of normal component of

force “Pn” and the total effect of unsteady aerodynamic

forces and moments (РUAI) will be always the highest

in the considered moment of time. If there are changes

in the direction of reciprocating movement, the work of

normal component of force “Pn” of flow effect P on the

lateral surface of working item will be equal to zero

(Formula 42 [1]).

The total UAI of unsteady aerodynamic forces and

moments (РUAI) also takes a null-value, as the value of

UAI directly depends on flow speed [2], and of the

intensity of the interaction of working items with a

flow. Working item passes through zero angle of attack

due to the force of inertia.

According to the scheme of interaction of the device

with a fluid medium flow, shown in Fig. 3, the work of

the device is carried out as follows.

Working item 1 is placed in fluid medium flow 2

with angle “L” relative to flow movement 2. Working

item 1 can make reciprocating movements in the

direction which is perpendicular to the direction of

flow movement 2. At the same time working item 1

makes rotational movements around axis 6 (Figs. 1-2).

Fluid medium flow 2 (Fig. 3) affects working item 1 in

position “A” and creates certain force. This force

moves working item 1 in the direction perpendicular to

the direction of flow movement 2 and rotates working

item 1 around axis 6 (Figs. 1-2). The direction of

movement is shown by arrow.

There arise unsteady aerodynamic forces and

moments, their total UAI (equals to РUAI) coinciding

with the force of a flow. PUAI also moves working item

1 in the direction perpendicular to the direction of flow

movement 2 and rotates working item 1 around axis 6

(Figs. 1-2). The direction of movement is shown by

arrow.

Meanwhile, the vector of the normal component “Pn”

of the motive force of flow “P” and the vector of total

UAI “РUAI” (Fig. 3) coincide with the direction of

movement of working item 1. The resulting “Ps” of the

motive force of flow “P” is directed perpendicularly to

the lateral surface of working item 1. The angle “L”

between working item 1 and the direction of flow

movement decreases. When this happens, the magnitude

of the effect of flow 2 on working item 1 reduces.

In position “B”, working item 1 switches its

direction of movement. This makes angle “L” equal

zero, making the effect of flow 2 on working item 1

absent, so there is no total “РUAI”. Working item 1

passes through position “B” due to inertia caused by

the rotation of crank 8 (Figs. 1-2). After having

passed position “B” (Fig. 3), the angle “L” differs

from zero. Therefore, this forces “Pn” and “РUAI”

arise again, which coincide with the inertial force of

crank 8 (Figs. 1-2) and move working item 1 to

position “С” (Fig. 3).

After having passed position “C” the angle “L”

increases. The vector of the normal component “Pn”


206

of the motive force of flow “P” and the vector of total

UAI coincide with the direction of movement of

working item 1. The resulting “Ps” of the motive

force of flow “P” is directed perpendicularly to the

lateral surface of working item 1. The maximum

effect of flow 2 and “РUAI” on working item 1 is in

positions “A” and “C”. The angle “L” reaches its peak

and is equal to 45 degrees (in this case). After having

passed position “C” the angle “L” decreases. The

magnitude of flow effect 2 and the total UAI on

working item 1 also decreases.

In position “D” working item 1 switches its direction

of movement. The angle “L” is equal zero, making the

effect of flow 2 and total UAI on working item 1 absent.

Position “D” working item 1 passes due to inertia caused

by the rotation of crank 8 (Figs. 1-2). After having

passed the position “D” (Fig. 3), the angle “L” differs

from zero. There is the force which coincides with the

inertial force of crank effect 8 (Figs. 1-2) and moves

working item 1 to position “A” (Fig. 3). The angle “L”

increases. The vector of normal component “Pn” of the

motive force of flow “P” and the vector of total UAI

“РUAI” coincide with the direction of the movement of

working item 1. The resulting “Ps” of the motive force

of flow “P” is directed perpendicularly to the lateral

surface of working item 1. Then, the process repeats.

10. Interaction of Four Module Device with a Fluid Medium Flow

There are three tasks that are considered in this work;

firstly, to reproduce the self-oscillations of flutter type;

secondly, to learn how to manage these

self-oscillations; thirdly, to obtain additional energy

generated by self-oscillations of flutter type.

The device consists of several individual working

items which form a part of independent modules.

Self-oscillations of flutter type can arise in

circumstances where there are at least two types of

movements in the oscillating system [2]. Working

items of the device make two types of rotation

simultaneously. The first one is reciprocating

movements of working items which are perpendicular

to the direction of a fluid medium flow movement. The

second one is the rotation of working items relative to

the axis of fastening of working item on the connecting

rod. There is the effect of a fluid medium flow on each

working item, and there is also the effect of UAI of a

flow and UAI of neighboring working items which are

transmitted with help of the flow.

The scheme of the device which consists of 4

modules is shown in Figs. 4-5.

Fig. 4 Scheme of the device, consisting of 4 modules—Front view.

Fig. 5 Scheme of the device, consisting of 4 modules—Rear view.


207

Indicating details on Figs. 4-5 and Figs. 1-2 are

similar.

Kinematical connection between modules is

implemented with the help of transmission gears 10

which are placed on shafts 9. Shafts are placed on the

stationary base. Phase shift between the modules

happens with help of transmission gears 10.

When using this scheme the irregularity of

movement of working item 1 is decreasing due to the

change of the direction of the movement of slider 5

when crossing “dead” points (positions “B” and “D” in

Fig. 3). Reliability and efficiency of the device’s work

at the interaction with the flow also increases.

Transmission gears also play the role of inertial

masses.

The scheme of uniform oscillating movement of

working items 1 of a four module device is shown in

Fig. 6.

This scheme provides a guaranteed mode of

self-oscillations of flutter type in the interaction with

fluid medium flow 2.

Fig. 6 The scheme of interaction of four modular device with the flow of a fluid medium.

Key for schemes:

1: Working item;

2: Fluid medium flow;

P: Force of the flow effect on the lateral surface of a

working item which is perpendicular to reciprocating


Pn: Normal component of the force of flow effect “P”

on the lateral surface of a working item which

coincides with the direction of the reciprocating


Ps: Resulting component of force “P” which is

perpendicular to the lateral surface of a working item;

РUAI: Total UAI of unsteady aerodynamic forces and

moments;

UAI: Unsteady Aerodynamic (or hydrodynamic)

Influences;

L: Angle of phase shift between movement and force

P;

A: Reference point;

1/1(1): Position of first working item in the reference

point;

1/2(1): Position of second working item in the

reference point (phase shift relative to first item of 90

degrees);

1/3(1): Position of third working item in the

reference point (phase shift relative to second item of

90 degrees);

1/4(1): Position of fourth working item in the

reference point (phase shift relative to third item of 90

degrees);

B: Phase shift of 90 degrees relative to the reference

point;

1/1(2): Position of first working item with phase

shift of 90 degrees relative to the reference point;

1/2(2): Position of second working item (phase shift

relative to first item of 90 degrees);

1/3(2): Position of third working item (phase shift

relative to second item of 90 degrees);

1/4(2): Position of fourth working item (phase shift

relative to third item of 90 degrees);

C: Phase shift of 180 degrees relative to the


208

reference point;

1/1(3): Position of first working item with a phase







relative to third item of 90 degrees);

D: Phase shift of 270 degrees relative to the

reference point;

1/1(4): Position of first working item with a phase







relative to third item of 90 degrees).

The arrows show the directions of reciprocating

movements of working items 1. These movements are

due to the effect of flow 2 and total effect of UAI on

working items 1. The angle of phase shift between the

movements of neighboring working items 1 is adjusted

with help of transmission gears 10 (Fig. 5). In this

example (Fig. 6) the angle of phase shift between the

movements of neighboring working items 1 is equal to

90 degrees.

In the interaction of fluid medium flow 2 with

working items 1/1, 1/2, 1/3 and 1/4 of four module

device (Fig. 6) arise forces “Pn” and “РUAI” which

coincide with the direction of working items

movement.

This makes total effect of flow and UAI (position A

is the reference point) on working item 1/1 maximal

(position 1/1(1), angle “L” = max). There is no effect

from flow 2 and UAI on working item 1/2 (position

1/2(1), angle “L” = 0). The total effect of flow and UAI

on working item 1/3 is maximal (position 1/3(1), angle

“L” = max, the direction of movement is opposite to the

direction of working item movement 1/1). There is no

effect from flow 2 and UAI on working item 1/4

(position (1/4(1), angle “L” = 0).

When crank 8 turns to 90 degrees (Fig. 4), working

items 1/1 and 1/3 (Fig. 6, position B—the turn of crank

8 to 90 degrees relative to the reference point) will take

position 1/1(2) and 1/3(2). In this case there is no

interaction of working items 1/1(2) and 1/3(2) with

flow 2, as angles “L” = 0. Working items 1/2 and 1/4

take positions of 1/2(2) and 1/4(2) accordingly. The

total effect of flow 2 and UAI on working items 1/2(2)

and 1/4(2) will be maximal due to the maximal angle of

attack “L”.

Then the process of movement repeats after each 90

degrees of crank 8 rotation (Fig. 4) (Fig. 6, position C –

the turn of crank 8 to 180 degrees relative to the

reference point; the position D—the turn of crank 8 to

270 degrees relative to the reference point). The total

force arising from the interaction of all working items 1

with flow 2, transmits to shaft 9 of any transmission

gear 10 (Fig. 5). Any transmission gear 10 can be

connected with the generator shaft (in Fig. 5 it is not

shown). This total force is equal to the total force of the

effect of flow 2 and UAI on all working items 1 of four

module device simultaneously.

With the further increase of the number of working

items, the scheme of interaction with a fluid medium

flow of the many module device will be similar to the

scheme of interaction with a fluid medium flow of the

four module device.

11. Experimental Laboratory WHD-1 (Wind-Hydro Device)

The experimental laboratory WHD-1 was designed

on the basis of materials presented in papers [18-20]. It

was a platform, made in the form of a rectangular plate.

There could be 1 to 8 modules with researched working

items installed on the platform (Figs. 4-5).

Platform size: 180 mm × 320 mm

Modules in quantities of 8 units were placed along

platform 4 according to the scheme, similar to the

scheme shown in Figs. 4-5.


209

The length of crank 8 Lcr = 22 mm measured the

amplitude of reciprocating movements of working

items 1: A = 2 × Lcr = 44mm (2)

Working items 1 were made in the form of

rectangular plate with the following parameters:

Width, b = 64 mm;

Height, h = 172 mm;

Thickness of plate, t = 1.0 mm.

The material of working items is dural D16T.

Area of working item Swi = b × h = 0.29 sq.m. (3)

Working items 1 were placed in two rows, four

working items in each row.

The angle of phase shift between neighboring

working items in each row is equal to 90 degrees.

The angle of phase shift between neighboring rows

is equal to 180 degrees.

12. The Aerodynamic Stand for Experimental Studies

All of the experiments concerning the research of

interaction of the experimental laboratory device with

air flow were held from 1990 to 1992 on the

aerodynamic stand ADS-2 (Certificate № 4/89 from

09.14, 1989, the Institute of Problems of Strength, the

Academy of Sciences of Ukraine). The aerodynamic

stand ADS-2 is designed for research of unsteady

aerodynamic forces and moments (UAI). These UAI

arise as a result of interaction of oscillating working

items with air flow. The frequency of oscillations can

be from 0 up to 1000 Hz in air flow at the speed of no

more than 300 m per second. The scheme of the

aerodynamic stand is shown in Fig. 7.

Air flow 1 is forwarded to air tube 2 through calming

grate 3 and to chamber 4 by a compressor of high

pressure (not shown in figure). Then, air flow 1 passes

calming grate 5, chasing nozzle 6, nozzle 7 and arrives

to working chamber 8. In working chamber 8, air flow

1 interacts with working items 9, and through diffuser

10, goes out to the atmosphere. The aerodynamic stand

construction provides the uniformity of flow and laminar

Fig. 7 The scheme of the aerodynamic stand ADS-2.

flow in working chamber 8.

Working chamber 8 is a closed part of the

aerodynamic stand. The cross-section of working

chamber is 150 × 180 mm and the length is 320 mm.

Working chamber 8 has detachable lateral walls.

During the tests, platform 13 of WHD-1 was installed

instead of one detachable lateral wall. Working items 9

were inside working chamber 8. Shafts 11 and

transmission gears 12 were outside of working

chamber 8. This made it possible to easily change the

angle of phase shift between neighboring working

items and install the generator of constant current on

shaft 11 of any module of working item 9.

Working items 9 interact with air flow 1 and start

moving. Their movement sets in motion shafts 11

installed on platform 13.

The speed of air flow 1 in working chamber 8 is

determined by the difference of static pressure in

different cross-sections of the aerodynamic tube

(Bernoulli equation for incompressible fluid and the

equation of continuity).


210

The pressure measuring of air flow 1 was made with

the help of sensors of static pressure. Sensors were

located at a distance of 23 mm in front of the entrance

of air flow 1 into working chamber 8; at a distance of

50 mm, 200 mm, 315 mm from the beginning of

working chamber 8; at a distance of 26 mm behind

working chamber. In addition, the static pressure

sensors were located in the cross-section of chamber 4.

There were three static pressure sensors in each

cross-section.

The pressure of air flow in different cross-sections of

the aerodynamic stand ADS-2 is determined by the

water manometers. The water manometers are glass

tubes filled with distilled water to a certain level.

13. The Experimental Research of Interaction of the Laboratory Device WHD-1 with Air Flow

The methodology of the tests was developed on the

basis of the materials presented in works [18, 21-24].

If working item 1 is motionless, unsteady

aerodynamic forces and moments are equal to zero (Fig.

3). Under the influence of air flow 2, working item 1

starts to move along the trajectory, provided by device

WHD-1. Working item 1 makes reciprocating and

rotary movements. This is the condition of UAI

appearance. During its movement, working item 1

overcomes the forces of mechanical damping (the

friction in the junctions of transmission gears and

toothing) and aerodynamic damping. Unsteady

aerodynamic forces and moments arise and grow from

zero to its maximal value. The magnitude of UAI

depends on the kinetic energy of a flow and the

intensity of interaction of the working item with the

flow. Mechanical energy of reciprocating and rotary

movements of the working item transforms into

mechanical energy of the rotation of crank shaft 9 (Fig.

1). Connecting rod 3 and crank 8 are auxiliary

mechanisms for transmitting energy. Further

transformation of energy of crank shaft into electrical

energy with the help of the generator installed on the

shaft crank is not difficult. The only condition for

getting the useful work in the shown scheme is that the

initial rotation of crank shaft (or shaft of the generator)

should be without any load. After UAI reaches its

maximal value and shaft crank reaches its maximal

rotations, the load on the generator can be given and

electrical energy can be received.

In the process of making experiments on the

aerodynamic stand ADS-2 the speed of air flow at the

entrance into the working chamber and number of

researched working items were changed.

Measured parameters: Drop of the static pressure at

the height of the working chamber, the current strength

and voltage withdrawn from shaft of generator.

Calculated parameters: Air flow speed; wind flow

power; electrical energy generated by direct current

generator; efficiency of laboratory device WHD-1

during the interaction of its working items with air flow.

In Fig. 8 there are shown the graphs of air flow speed

in the working area of the aerodynamic tube depending

on the number of working items (without taking useful

work). The speed of free air flow of at the entrance into

the working chamber is constant and equal to 62 m/sec.

Fig. 8 Change of speed of the air flow in the interaction with the working item without removing of useful work.


211

The same speed of incoming air flow was kept while

filling working chamber with working items. Working

items were set in motion by air flow without taking

useful work.

The research was conducted with two, four, six and

eight working items.

Key for schemes:

L0: length of working chamber of aerodynamic

stand;

L1: location of working items along working

chamber;

57.5, 127.5, 197.5 and 267.5: distances from the

beginning of working chamber to axes of rotation of

working items, located on platform of device WHD-1;

№1-№ 5: the location of static pressure sensors

along working chamber;

n: number of working items;

V (m s-1): air flow speed;

L (mm): distance from the beginning of working

chamber.

The arrow shows the direction of movement of air

flow.

The graph shows that the velocity of all air flows at

the inlet to the working chamber of a little less than the

rate of free (undisturbed) flow. After first working item

velocity of air flows is almost identical. And further

increase in the speed of air flows along the working

part depending on the number of working items.

Silk threads were on the lateral surfaces of working

items. In addition, silk threads were attached to probe,

made in the form of needle. Probe inserts along the

working chamber in different cross-sections. The

movement of silk threads in air flow points the laminar

current of air flow along the working chamber. In the

case of turbulence of flow before getting into the

working chamber, the laminirization of flow occurs

directly after first working item.

Drawings showing connection between extracted

power, net efficiency and air flow speed “V” and

number of investigated working elements “n” are

shown on Figs. 9-10, respectively.

Fig. 9 Schedule power change.

Fig. 10 Schedule of changes in efficiency.

Extracted power and net efficiency increase

proportionally to the increase of the flow speed and

number of investigated working elements.

Drawings showing changes of the air flow speed and

pressure in cases when the working element is

represented by a usual screw and the investigated plant

are shown on Figs. 11-12, respectively.


212

Fig. 11 Drawings showing changes of the air flow speed and pressure in cases when the working element is represented by a usual screw.

Fig. 12 Drawings showing changes of the air flow speed and pressure in cases when the working element is represented by a investigated plant.

Key for schemes:

D (mm): The diameter of the screw;

L (mm): The distance;

L0 (mm): The length of the wind tunnel;

L1 (mm) = (9-15) D: The distance required for the

restoration of the kinetic energy of the flow of air after

the interaction with the screw;

L2 (mm): The length of the investigational device;

P (kg cm-2): Pressure airflow;

P0 (kg cm-2): The pressure of the undisturbed air flow;

+∆p (kg cm-2): Increasing the pressure of the air flow;

-∆p (kg cm-2): Reducing the pressure of the air flow;

V (m s-1): Air flow speed;

V0 (m s-1): The speed of the undisturbed air flow;

+∆V (m s-1): Increasing air velocity;

-∆V (m s-1): Reduction in air velocity;

The arrow shows the direction of movement of air

flow.

On the drawings we can clearly see differences in

change of the air flow pressure and speed during

interaction with a usual screw and the investigated

plant located in the same working chamber of an

aerodynamic tunnel. In the investigated device there

are practically no pressure and speed drops at the input,

while at the output of the device there is insignificant

increase of the air speed. Besides that, lack of the

pressure drop at the input of this device indicates lack

of overturning moment on the device. Behind the wind

motor screw (Fig. 11) there is a so called dead zone at a

distance of (9-15) D (where D—screw diameter), i.e.,

the distance necessary to restore the air flow power,

while in the investigated device (Fig. 12) there are no

such dead zones.

14. The Results of the Aerodynamic Research

(1) The laboratory device was constructed; it is

capable to reproduce self-oscillations of the flutter type;

(2) The possibility to manage UAI is confirmed;

(3) The possibility of converting the kinetic energy

of air flow into useful work during self-oscillations of

working items is confirmed;


213

(4) There are virtually no jumps in pressure and

speed at the entrance into device WHD-1 during the

taking of useful work. This points the absence of

overturning moment on the device;

(5) There is the laminar current along the working

part and behind working items with any number of

working items, even in such a circumstance when the

flow is turbulized before getting into the device;

(6) The increase of the speed of air flow behind

working items in comparison with the speed of air flow

before working items points to the appearance of UAI;

this leads to the increase of the kinetic energy of flow;

(7) There is a proportional increase in the capacity

and the efficiency of the device with the increase of the

flow speed and the number of working items;

(8) The conducted experiments confirm the

possibility to increase the capacity of the device by

connecting additional working items along the device;

(9) This device makes effective conversion of the

kinetic energy of a flow into electrical energy in

comparison with the common blades of propellers,

widely used for the conversion of the kinetic energy of

air or water flow into electrical energy.

(10) The “secret” of the speed of a dolphin

movement is explained by the continuous

bending-torsion movements of the dolphin’s body parts

from head to tail in the interaction with water, which

causes the appearance of UAI. The directions of

bending-torsion movements are perpendicular to the

movement of the animal.

The results of the experiments of laboratory device

WHD-1 conducted on the aerodynamic stand

confirmed the theoretical assumption that it is possible

to convert the kinetic energy of air flow into electrical

energy due to the total work of the motive forces of the

flow and UAI.

15. Experimental Research of the Laboratory Device WHD-1 in the Water Environment

The next stage of the research of the device WHD-1

was experiments on the mooring regime. The working

environment was water.

The goal of the experiments was to check the

functionality of the device WHD-1 in the water

environment.

The methodology of the mooring trials of the

laboratory device is similar to the methodology of

mooring trials of the usual ships. This excluded the

probability of methodological mistakes during

experiments.

The device was installed on the platform and

consisted of eight modules. In the device, everything

was located in the same way as during experiments in

air flow. In addition, there was produced another

similar device that was connected to the first one.

Working items of the researched devices share the

common drive. There is a possibility to transfer the

energy of the flow (or movement) from one working

item to another on the shared drive.

The scheme of the laboratory device WHD-1 in water

flow in the mode of propulsion is shown in Fig. 13.

There are eight working items in each of two

researched devices of module type. They were installed

on common platform 1 and had the common drive

connected with shaft 2 of constant current engine 3. The

Fig. 13 Hydrodynamic stand.


214

engine is set in motion by two sources of constant

current 4 which are sequentially connected (the total

voltage is equal to 24 V). The engine transmits the

movements to the working items of the devices with

the help of common drive and transmission gears (Fig.

13).

Working items (not shown in figure) in this

experiment are the movers. During the interaction with

water, working items make platform 1 perform forward

movements. Researched modules are located on

platform 1. The platform is suspended by thin metal

strings 5. Working items are immersed into water

which fills pool 6. Platform 1 is connected by

dynamometer 7 with the base 8. Base 8 has the freedom

of movement relative to platform 1. There is the

indicator of zero level 9 of platform movement on the

distant side of pool 6.

Working items are immersed in water and are not

shown in Fig. 13.

During experiments, the number of working items

and their surface area were changed. The number of

rotations of constant current engine did not change.

Measured parameters: thrust force developed by the

device.

The experiment is as follows. The effort of engine 3

through shaft 2 of common drive is transmitted to

working items. Working items interact with water and

set in motion platform 1. Platform 1 moves relatively to

the indicator of zero level 9. In order to exclude the

influence of strings 5, it is necessary to return the front

edge of platform 1 to one level with the indicator of

zero level 9. To return platform to this position the

mechanical force must be made to be at base 8 in the

direction opposite to the direction of platform 1

movement. Base 8 is connected with platform 1 with

help of dynamometer 7. According to dynamometer

scale 7, we define thrust force developed by working

items.

Two series of experiments were conducted. In the

first experiment of the first series sixteen working

items of both devices were involved. Platforms of the

devices were connected sequentially. Working items

have developed the force equal to 115 conventional

units of dynamometer scale.

In the second experiment, twelve working items

were involved, four items were removed. Working

items developed the force equal to 62 conventional


In the third experiment one device was disconnected.

There were 8 working items in the process. Working

items developed the force equal to 37 conventional


In the fourth experiment, four working items were

involved. Working items developed the force equal to

14 conventional units of the dynamometer scale.

In the second series of experiments, the area of the

surface of working items was almost reduced by 2

times. The experiments were similar to the experiments

of the first series. Working items developed forces

equal in accordance to 70, 38, 21 and 9 conventional


Graphs of dependence of thrust force “P” on number

“n” and area “s” of working items are shown in Fig. 14

(working environment is water).

The graphs clearly indicate the increase of thrust

force depending on number “n” and area “F” of

working items.

Fig. 14 Graphs of dependence of thrust force “P” on number “n” and area “s” of working items.


215

Results of laboratory test setup, in an aqueous

medium obtained confirmed the test results obtained in

the air.

16. Conclusions

The main difference of the device using effective

work of UAI from traditional wind generators and

hydraulic generators of propeller type is that it has no

overturning moment. As a result, there is no need to

construct complicate hydraulic facilities (dams, dikes)

for hydraulic plants or to lay solid foundations to

strengthen masts of wind plants. The plant is simply

placed into the water flow or air flow and that is it, the

plant produces electric energy. The plant is simply

installed on the roof of the house, low rise or high rise,

or on a dike or a dam, or on a ship deck, and that is it,

the plant functions. At the same time there is no hazard

of deterioration of the roof of the house or of the dam,

dike, or the ship deck; electric energy is produced

safely.

Results of conducted mooring tests confirmed a

possibility of proportional increase of tractive force

due to increase of the power plant capacity or increase

of a sea craft speed due to increase of the driven shaft

speed. In this situation the sea craft consumes less fuel

or moves faster with the same fuel consumption.

Unlike generally accepted screw propellers these

propellers do not turbulize water flow, as a result 85 %

of the ship engine power is used not for the flow

turbulization, but for effective work on creation of

additional traction necessary for movement. Lack of

overturning moment during interaction of the propeller

with water environment allows to count on significant

increase of the ship speed. Location of working

elements along the length of the ship hull will make it

possible to exclude (or to significantly decrease)

coefficient of friction between the ship hull and the

water flow due to creation of dynamic pressure

negative gradient along the length of the ship hull.

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