
Archive issue  vol.7 No.4
No. 
Author(s)  Title 
Pages 
1. 
 Professor Ken Walters  the Weissenberg Award Winner 
10891093 
2. 
K.M.Arefiev and S.V.Shevkunov  Computation of transport and equilibrium properties of molecular systems with quantum mechanical calculation of interaction potentials 
10951123 
3. 
V.K.Bhatt  Application of refined thermal Reynolds equation in the analysis of hydrodynamic lubrication of strip rolling 
11251139 
4. 
R.C.Chaudhary and T.Chand  Three dimensional flow and heat transfer through a porous medium 
11411156 
5. 
V.Dolej, B.ika, R.Teichman, P.Doleček and P.Brokl  Motion of a single solid and fluid sphere in viscoplastic fluids and viscoplastic fluid flow through fixed beds: a unified solution 
11571172 
6. 
H.Dumitrescu and V.Cardoş  A twodimensional vortex model for vertical axis wind turbines 
11731187 
7. 
H.V.Ersoy and S.Bariş  Flow of a second order/grade fluid due to noncoaxial rotation of a porous disk and the fluid at infinity 
11891199 
8. 
J.Fydrych, K.JeżowieckaKabsch and H.Szewczyk  Equation of the pulsating axiallysymmetrical liquid flow in a pipe with a constriction 
12011209 
9. 
S.K.Ghosh, I.Pop and D.K.Nandi  MHD fully developed mixed convection flow with asymmetric heating of the wall 
12111228 
10. 
J.R.Lin  Magnetohydrodynamic lubrication of finite slider bearings 
12291246 
11. 
J.R.Lin and Ch.F.Chiang  Effects of surface roughness and rotational inertia on the optimal stiffness of hydrostatic thrust bearings 
12471261 
12. 
S.Mahmud, A.K.M.Sadrul Islam and M.A.H.Mamun  Separation characteristics of fluid flow in a pipe with wavy surface 
12631278 
13. 
M.C.Manna, S.Haldar and A.K.Bhattacharya  Bending analysis of isotropic plates using a sixteennoded subparametric element 
12791290 
14. 
J.Stelmach and E.Rzyski  The application of sample and hold method in the processing of data obtained from a laser doppler anemometer 
12911303 
15. 
R.P.Thangaraj  Nonlinear spectral analysis of RayleighBenard convection in a highporosity medium 
13051328 
16. 
K.L.Verma and N.Hasebe  On the dynamic responses with and without energy dissipation in the thermoelastic rotating media 
13291348 

2.
COMPUTATION OF TRANSPORT AND EQUILIBRIUM PROPERTIES OF MOLECULAR SYSTEMS WITH QUANTUM MECHANICAL CALCULATION OF INTERACTION POTENTIALS
K.M. AREFIEV, S.V. SHEVKUNOV
St. Petersburg State Technical University
St. Petersburg, 195251, Politehnicheskaya 29, RUSSIA
The computation of transport coefficients in gases on the basis of molecular theory requires the determination of interaction potentials. As a rule, the dependencies of interaction energy on the distances between the molecules extracted from experimental data on different measurable characteristics are used. At the same time, direct calculation of interaction potentials on the basis of approximate solution of Schroedinger equation is possible for a number of relatively simple in their electron structure, but important for applications systems. Mixtures of the vapors of the atoms of metals with noble gases represent a typical example of such systems. In this paper, a comparison between experimental and calculated diffusion coefficients of the vapors of metals in the first and the second groups of Periodic Table dissolved in noble gases is presented. A sufficient for practical needs convergence of numerical results is demonstrated. The interaction potentials obtained can be used in the calculations of other transport coefficients, such as viscosity and thermal conductivity, in the mixtures of the vapors of metals with gases.
Along with the traditional approach based on Schroedinger formalism, modern alternative methods of quantum mechanics and quantum statistics are presented. One example is the Path Integral Monte Carlo method based on Feynman representation of quantum mechanics. This formalism makes it possible to solve quantum statistical problems for thermally excited electron states and in this way to simulate numerically equilibrium properties of dense nonideal plasma. Exchange and all correlation effects can be described in this formalism in an explicit way. Another modern approach aimed at stochastic simulations of electron quantum states is the socalled Diffusion Method, representing a solution of Schroedinger equation in imaginary time. Applications of stochastic methods in the problems of thermodynamics and plasma physics are presented. The perspectives and possible directions of development of new methods in the statistical description of condensed matter is briefly discussed.

Key words: 
thermodynamics, diffusion, intermolecular interaction, computer simulation, statistical mechanics, plasma. 
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3.
APPLICATION OF REFINED THERMAL REYNOLDS EQUATION IN THE ANALYSIS OF HYDRODYNAMIC LUBRICATION OF STRIP ROLLING
V.K. BHATT
Mechanical Engineering Department
Bundelkhand Institute of Engineering and Technology
Jhansi  284001 (U.P.) INDIA
email: bhatt_biet@yahoo.com
A refined thermal Reynolds equation considering conduction and convection modes of heat transfer across the film for inlet zone of the liquid lubricated strip rolling, developed by Bhatt and Sengupta, is applied in this analysis. It is known that inlet zone plays a dominant role in fixing the lubricant film thickness in the work zone. Hence, for the present analysis the effect of conduction and convection across the film in the inlet zone is studied on the work zone as well as the effect of variation of convection effect in the form of variation of the Peclet number. It is observed that the roll separating force and torque decrease with increasing the Peclet number.

Key words: 
strip rolling, hydrodynamic lubrication, thermal effects, Peclet number. 
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4.
THREE DIMENSIONAL FLOW AND HEAT TRANSFER THROUGH A POROUS MEDIUM
R.C. CHAUDHARY and T. CHAND
Department of Mathematics, University of Rajasthan
Jaipur  302004, INDIA
email: ramacharanchaudhary@rediffmail.com
The effect of permeability on the heat transfer and the flow through a highly porous medium bounded by an infinite porous surface is investigated. The periodic transverse suction velocity is applied to the surface due to which the flow becomes threedimensional. The surface is kept at oscillating wall temperature. Analytical expressions for velocity, temperature, skin friction and rate of heat transfer are obtained. The important characteristics of the problem, the skin friction and the rate of heat transfer are discussed in detail with the help of graphs and tables.

Key words: 
threedimensional flow, porous medium, heat transfer, periodic suction. 
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5.
MOTION OF A SINGLE SOLID AND FLUID SPHERE IN VISCOPLASTIC FLUIDS AND VISCOPLASTIC FLUID FLOW THROUGH FIXED BEDS: A UNIFIED SOLUTION
V. DOLEJ, B. IKA, R. TEICHMAN, P. DOLEČEK and P. BROKL
Department of Chemical Engineering, University of Pardubice
53210 Pardubice, CZECH REPUBLIC
email: Vaclav.Dolejs@upce.cz
An approach to the calculation of drag and fall or rise velocity of a solid and Newtonian fluid spheres in viscoplastic fluids and to the calculation of pressure drop in viscoplastic fluid flow through random fixed beds of particles is suggested. It is based on the application of the modified RabinowitschMooney equations together with corresponding relations for consistency variables and on the application of the relationship of HadamardRybczynski valid for both the fluid and solid spheres. The solution is concretized for Bingham, Casson and RobertsonStiff flow models, and in the case of fixed beds also for HerschelBulkley flow model.

Key words: 
sphere motion, fluid sphere motion, fixed bed, viscoplastic fluids, nonNewtonian fluids. 
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6.
A TWODIMENSIONAL VORTEX MODEL FOR VERTICAL AXIS WIND TURBINES
H. DUMITRESCU and V. CARDOŞ
"Caius Iacob" Institute of Applied Mathematics
P.O. Box 124, RO70700, Bucharest, ROMANIA
email: horiad@ns.ima.ro
The present paper compares the aerodynamic loads predicted by a vortex model with wind tunnel measurements for a straightbladed Darrieus rotor. A computation unsteady discretevortex method, based on lifting line theory and a free vortex wake model, is used. Thus the wake is composed of shedding spanwise discrete vortices, whose strengths are equal to the change in the bound vortex strength as dictated by Kelvin's theorem and performance parameters are calculated by application of the BiotSavart law along with the KuttaJoukovski theorem. The popular BeddoesLeishman dynamicstall model is incorporated in the method and a better approach is obtained. The transient normal and tangentialforce coefficients predicted with dynamicstall effects are compared with wind tunnel data for one and two NACA 0018 straightbladed rotors. The results are given for a rotor with a large solidity (chordtoradius of 0.20) at two tipspeed ratios ('lambda' = 1.5 and 3.0) and at a low Reynolds number of 3.8*10^{4}. The comparisons between experimental data and theoretical results show the predictions by the marchingvortex method to be more accurate than those estimated by a code based on streamtube theory.

Key words: 
aerodynamics, unsteady flows, vortex methods, dynamic stall, wind turbines. 
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7.
FLOW OF A SECOND ORDER/GRADE FLUID DUE TO NONCOAXIAL ROTATION OF A POROUS DISK AND THE FLUID AT INFINITY
H.V. ERSOY and S. BARIŞ
Department of Mechanics, Faculty of Mechanical Engineering
Istanbul Technical University
80191, Gümüşsuyu  Istanbul, TURKEY
email: volkan@mkn.itu.edu.tr
The flow of an incompressible second order/grade fluid due to noncoaxial rotation of a porous disk and the fluid at infinity with the common angular velocity is studied. It is shown that there are physically acceptable solutions for both suction and blowing cases, depending on the sign of the material modulus 'alpha'_{1} . It is observed that the elasticity of the fluid causes the boundary layer thickness to increase in the case of suction, whereas it causes the boundary layer thickness to decrease in the case of blowing.

Key words: 
disk, fluid rotating at infinity, noncoaxial rotation, second order/grade fluid. 
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8.
EQUATION OF THE PULSATING AXIALLYSYMMETRICAL LIQUID FLOW IN A PIPE WITH A CONSTRICTION
J. FYDRYCH, K. JEŻOWIECKAKABSCH and H. SZEWCZYK
Faculty of Mechanical and Power Engineering
Wroclaw University of Technology
Wybrzeże Wyspiańskiego 27
50370 Wrocław, POLAND
email: fydrych@fluid.itcmp.pwr.wroc.pl
In this paper, the results of theoretical studies on the unsteady liquid flow in a pipe with an element causing the occurrence of recirculation zones are presented. The model of unsteady flow in a pipe with a constriction has been developed. Starting from the principle of momentum conservation referred to a control volume, the differential equation of the flow has been obtained. From this equation, the relationship between the height of a hydraulic loss and the volume rate of flow for the pulsating liquid flow in a constricted pipe has been derived. In this relationship, an element allowing for the occurrence of recirculation zones and their time variation have been identified.

Key words: 
unsteady liquid flow, pulsating flow, pipe with a constriction. 
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9.
MHD FULLY DEVELOPED MIXED CONVECTION FLOW WITH ASYMMETRIC HEATING OF THE WALL
S.K. GHOSH
Department of Mathematics, Narajole Raj College
P.O. Narajole, Dist.: Midnapore, West Bengal, INDIA
I. POP
Faculty of Mathematics, University of Cluj
R  3400 Cluj, CP 253 ROMANIA
D.K. NANDI
Department of Applied Mathematics
Vidyasagar University, Midnapore, INDIA
Magnetohydrodynamic fully developed mixed convection flow of a viscous incompressible electrically conducting fluid confined to a vertical channel with asymmetric heating of the wall, is studied. It has been shown that a reversed flow occurs due to asymmetric heating of the wall when the magnitude of the buoyancy parameter Gr exceeds a certain threshold value. The limiting cases of the MHD free and forced convection flow are analysed. A qualitative discussion for the occurrence of a flow reversal is given in this paper. It is interesting to note that in the higher buoyancy the bulk temperature of the MHD flow exceeds the value 1 when r_{T} < 1.

Key words: 
mixed convection, buoyancy force, shear stress, bulk temperature, flow reversal. 
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10.
MAGNETOHYDRODYNAMIC LUBRICATION OF FINITE SLIDER BEARINGS
J.R. LIN
Department of Mechanical Engineering, Nanya Institute of Technology
P.O. Box 267, ChungLi 320, Taiwan, R.O.C.
email: jrlin@ms18.hinet.net
In this paper, the effect of a transverse magnetic field on the performance characteristics of finite slider bearings with an electrically conducting fluid is presented. To take account of the Lorentz force on the lubricant film, a generalized twodimensional Reynoldstype equation is derived by using the MHD motion equations with Maxwell equations. This MHD Reynolds equation is applicable to the analysis of finite slider bearings with different film shapes. To illustrate the MHD bearing characteristics, the slider profile with an inclined plane is considered. The film pressure is numerically solved from the MHD Reynoldstype equation and applied to evaluate the bearing characteristics. According to the results obtained, the application of the magnetic field signifies an influence on the load capacity, power loss and friction parameter of slider bearings, depending upon the values of the Hartmann number, aspect ratio and inletoutlet film thickness ratio.

Key words: 
electrically conducting fluids, transverse magnetic fields, finite slider bearings, lubrication characteristics. 
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11.
EFFECTS OF SURFACE ROUGHNESS AND ROTATIONAL INERTIA ON THE OPTIMAL STIFFNESS OF HYDROSTATIC THRUST BEARINGS
J.R. LIN
Department of Mechanical Engineering, Nanya Institute of Technology
P.O. Box 267, ChungLi, Taiwan, 320, R.O.C.
email: jrlin@ms18.hinet.net
Ch.F. CHIANG
General Education Center, ChingYun Institute of Technology
ChungLi, Taiwan, 320, R.O.C.
Based upon Christensen's stochastic model, this paper studies the optimal stiffness of hydrostatic thrust bearings including the effects of surface roughness and rotational inertia. The mean film pressure for a capillarycompensated circular step bearing is solved from the stochastic Reynoldstype equation together with the stochastic recess flow continuity equation. By applying the maximum principle, a closedform equation determining the critical recess pressure is obtained for the bearing operating at any given film thickness. From the results obtained, the apparent influence of surface roughness upon the maximum bearing stiffness is more pronounced with higher values of radius ratio, rotation number, and roughness parameter. For engineering practice, a guiding example for the optimal operation is also given.

Key words: 
surface roughness, rotational inertia, optimization, maximum stiffness, hydrostatic thrust bearings. 
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12.
SEPARATION CHARACTERISTICS OF FLUID FLOW IN A PIPE WITH WAVY SURFACE
S. MAHMUD and M.A.H. MAMUN
Department of Mechanical Engineering, University of Waterloo
200 University Avenue West, Waterloo, Ontario
CANADA, N2L3G1
email: smahmud@engmail.uwaterloo.ca
A.K.M. SADRUL ISLAM
Department of Mechanical Engineering
Bangladesh University of Engineering and Technology (BUET)
Dhaka1000, BANGLADESH
email: sadrul@me.buet.ac.edu
Separation characteristics of fluid flow in a pipe with sinusoidal wavy surface are investigated numerically. The pipe waviness is characterized by a wavelength ('lambda') and an amplitude (a) of the wave. Steady laminar flow of a Newtonian fluid is considered. Governing equations are discretized using the control volume based FiniteVolume method with collocated variable arrangement. SIMPLE algorithm is used and TDMA solver is applied to solve the system of equations. The length of the pipe is kept four times the wavelength (4*'lambda'). The effect of surface waviness, determined by the wavelengthamplitude ratio 'lambda'/a (=L^{*}) , on separation characteristics of fluid flow is presented. The simulation work has been carried out for L^{*}= 11.0  30.0 and for the Reynolds number ranging from 50 to 2000. The structure of separation bubble depends strongly on the waviness of the surface for a particular Reynolds number and changes a little with the wave number n. Finally the flow field is presented in the form of stream function and axial velocity profiles for understanding the separation phenomenon.

Key words: 
critical Reynolds number, separated flow, separation bubble, wall vorticity, waviness. 
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13.
BENDING ANALYSIS OF ISOTROPIC PLATES USING A SIXTEENNODED SUBPARAMETRIC ELEMENT
M.C. MANNA, S. HALDAR and A.K. BHATTACHARYA
Department of Applied Mechanics
Bengal Engineering College, (Deemed University)
Howrah  711 103, West Bengal, INDIA
email: mcmanna@appmech.becs.ac.in
Static analysis of isotropic plates under uniformly distributed and point loading is investigated in this paper. A sixteen noded subparametric element having fiftytwo degrees of freedom is developed for this purpose. The first order shear deformation theory (FSDT) has been used in the entire analysis. The transverse and inplane displacements and bending rotations are taken as independent field variables and the polynomials used to express these variables are of different orders.

Key words: 
static analysis, subparametric element, FSDT, aspect ratios, thickness ratios. 
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14.
THE APPLICATION OF SAMPLE AND HOLD METHOD IN THE PROCESSING OF DATA OBTAINED FROM A LASER DOPPLER ANEMOMETER
J. STELMACH and E. RZYSKI
Department of Process Equipment
Łód Technical University
Wólczańska 213, 93005 Łód, POLAND
email: stelmach@wipos.p.lodz.pl
Using a laser Doppler anemometer, liquid velocity was measured in the tank in which liquid was mixed by a selfaspirating disk impeller. The energy spectrum was the basis to determine the energy dissipation rate.
This rate determines the size of eddies that are formed in the vicinity of the impeller. Results obtained by sample and hold method were compared with those obtained by other methods. An increase in the sampling frequency caused a decrease in the mean liquid velocity at the measuring point.

Key words: 
agitation, laser Doppler anemometry, sample and hold method, energy spectrum, energy dissipation rate, selfaspirating impellers. 
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15.
NONLINEAR SPECTRAL ANALYSIS OF RAYLEIGHBENARD CONVECTION IN A HIGHPOROSITY MEDIUM
R.P. THANGARAJ
V.L.B. Janakiammal College of Arts and Science
Coimbatore, INDIA
email: kcrk@vsnl.com
A local nonlinear stability analysis using the spectral method is made of the RayleighBenard situation in a highporosity porous medium. The series expansion solution so obtained is valid for a large range of imposed temperature differences and yields a quantitative estimate of the heat transport by convection. Streamline patterns and mean temperature distributions have been obtained. The temperature distributions show that at the middle of the fluidfilled porous layer a layer of isothermal mean temperature develops, thus limiting the major heat transport to thermal boundary layers. The damping nature of porous media on heat transport is also clearly brought out.

Key words: 
convection, stability, adiabatic, isothermal, free and rigid boundaries. 
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16.
ON THE DYNAMIC RESPONSES WITH AND WITHOUT ENERGY DISSIPATION IN THE THERMOELASTIC ROTATING MEDIA
K.L. VERMA
Department of Mathematics
Government Post Graduate College Hamirpur, (H.P.)
177005, INDIA
klverma@netscape.net
N. HASEBE
Department of Civil Engineering
Nagoya Institute of Technology
GokioCho, ShowaKu, Nagoya 466, JAPAN
The generalized dynamical theories of thermoelasticity with and without energy dissipation are applied to study the propagation of thermoelastic waves in an infinite, homogenous, isotropic medium rotating uniformly with constant angular velocity. A generalized characteristic equation is derived to investigate the effects of rotation, the relaxation time constants and thermomechanical coupling on the dispersion behavior of thermoelastic waves. Results of earlier works are deduced as particular cases of the more general results obtained here.

Key words: 
generalized thermoelasticity, relaxation time, thermomechanical coupling, without energy dissipation, rotating media. 
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