
Archive issue  vol.2 No.3
1.
UNSTEADY, LAMINAR VISCOELASTIC
FLOWS THROUGH RECTANGULAR DUCTS
Karim RAHAMAN
Department of Mathematics and Computer Science
University of the West Indies, St. Augustine
R. OF TRINIDAD AND TOBAGO
The behaviour of a number of complex fluids, such as paints, blood and
polymers, which cannot be explained on the basis of the classical Newtonian
theory, has led to the development of the field of nonNewtonian fluids.
Upperconvected Maxwell fluids are a member of this class. The flow of these
fluids, through rectangular ducts, is examined when the axial pressure gradient
is an arbitrary function of time. The flow response due to an impulsive
pressure gradient at the start of the motion is first obtained. Thereafter, the
result for a constant pressure gradient is found by use the of a convolution
involving the impulse response. Quantities such as the drag and the friction
factor for this latter case have been obtained, and some numerical work is done
and comparisons made with Newtonian fluids .

Key words: 
viscoelastic, upperconvected Maxwell, rectangular ducts. 
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2.
DEVELOPMENT OF A QUASI 3D BOUNDARY LAYER
Melda Ö.Çarpinlioglu
Department of Mechanical Engineering
University of Gaziantep
Gaziantep 27310, TURKEY
In this paper results of an experimental investigation upon boundary layer development with an emphasis on transition to turbulence on a swept flat plate are presented. The investigation was conducted under a zero streamwise pressure gradient and referring to a classical example of a fully 3D boundary layer on a swept wing; the boundary layer on the test plate was called a quasi 3D one.
In order to determine the influence of the leading edge sweep angle, test plates with different leading edge sweep angles, 'lambda' (10°, 20°, 35° and 50°) were used. The characteristics of the flow field in transitional regime were evaluated through the measurements of mean velocity profiles along the centerline of the test plates. Based on the proposed correlations between the crossflow and mainflow parameters a radical change in the boundary layer growth seems to occur for 'lambda' > 35°. Furthermore, as rough estimates R_{'teta'} = 345, R_{cf} and R_{x}=1*10^{5} are suggested to be the critical values, below which the crossflow inside the boundary layer on a swept plate is not effective in transition.

Key words: 
quasi 3D boundary layer, crossflow, mainflow. 
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3.
MAGNETOHYDRODYNAMIC DISK BRAKING
Rama Subba Reddy GORLA, Karthikeyan RAMALINGAM
Mechanical Engineering Department
Cleveland State University
Cleveland, OH 44115, USA
Indrasena ADLURI
Department of Mathematics
Wheeling Jesuit College
Wheeling, West Virginia 26003, USA
A viscous fluid separates a rotating disk and a parallel non rotating disk. A magnetic field of intensity B_{0} is applied perpendicular to the disks. As the two disks are squeezed closer together, increased viscous torque is transmitted to the rotating disk. The nonsimilar problem is solved for the condition of the top disk moving with constant velocity. The effect of magnetic field on the braking action is discussed.

Key words: 
magnetohydrodynamics, braking, rotating disk. 
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4.
NONLINEAR BENDING OF CORRUGATED ANNULAR
PLATE WITH LARGE BOUNDARY CORRUGATION
RenHuai LIU
Institute of Mathematics and Mechanics
Jinan University
Guangzhou, 510632, P.R.CHINA
Hong YUAN
Department of Civil Engineering
Guangdong University of Technology
Guangzhou, 510090, P.R.CHINA
By using the simplified Reissner's equations of axisymmetric shells of
revolution, the nonlinear bending of a corrugated annular plate with a large
boundary corrugation and a nondeformable rigid body at the center under a
concentrated load has been investigated. The characteristic curves and the
stress distribution in the plate are obtained by means of the method of integral
equation.

Key words: 
corrugated circular plate, large boundary, corrugation, nonlinear bending. 
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5.
THE SQUEEZING OF A MICROPOLAR
FLUID BETWEEN TWO PLATES
H.S. TAKHAR
Department of Engineering
University of Manchester
Manchester, M13 9PL, UK
R.S. AGARWAL and R. BHARGAVA
Department of Mathematics
University of Roorkee
Roorkee247667, INDIA
The flow of a micropolar fluid between two parallel plates, which are being
squeezed, is discussed. With the normal velocity taken as time dependent, the
governing unsteady equations are solved numerically using a doubleshooting
technique. The velocity and microrotation function depend upon two parameters,
viz., the micropolar parameter and the parameter accounting for unsteadiness.
The effects of these parameters on the flow and microrotation functions are
shown graphically.

Key words: 
micropolar flows, squeezing of films. 
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6.
DEFORMATION MECHANICS OF THE SPRINGBACK IN UBENDING
FuhKuo CHEN and MingTeh CHAO
Department of Mechanical Engineering
National Taiwan University
Taipei, Taiwan, R.O.C.
The deformation mechanics of the springback occurring in the Ubending was
investigated in the present study. A theoretical model was first developed to
analyze the momentcurvature relations throughout the bent sheet, taking
necessary process parameters into account. The finite element simulations were
also applied to determine the sensitive process parameters affecting the
springback. In addition, the deformation mechanism of the doublebend technique
was examined in detail using the finite element analysis. It was found that the
springback can be effectively reduced if an additional bending operation, which
can develop the deformation mechanism similar to that introduced in the
doublebend technique, is applied.

Key words: 
springback, Ubending, theoretical model, finite element method, doublebend. 
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7.
FORCED CONVECTION RADIATION INTERACTION
HEAT TRANSFER IN BOUNDARYLAYER OVER A
FLAT PLATE SUBMERSED IN A POROUS MEDIUM
M.A.MANSOUR
Mathematics Departmen
Faculty of Science
Assiut University, Assiut, EGYPT
The interaction of forced convection and thermal radiation during the flow
along a flat plate in a porous medium of a variable viscosity is studied. The
Rosseland approximation is used to describe the radiative heat flux in the
energy equation. The viscosity of the fluid is taken as an inverse linear
function of temperature.

Key words: 
forced convection, radiation, boundary layer. 
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8.
EFFECT OF THE SIDE WALLS ON THE FLOW
OVER A MOVING PLANE WALL
M.Emin ERDOGAN
Instanbul Teknik Üniversitesi
Makina Fakültesi 80191, Gümüssuyu
Istanbul, TURKEY
The effect of the side walls on the steady flow of a viscous fluid over a
plane wall moving at a constant speed is considered. For this purpose, three
different boundary conditions are used. In the first case, the flow is extended
to infinity; in the second case, the flow is bounded by a horizontal plane at
the top; in the third case, the flow is bounded by a free surface at the top.
For the three types of flows considered, it is shown that a difficulty arises in
the calculation of the shear stress at the bottom wall and a solution is
presented to overcome this difficulty. Furthermore, it is shown that the effect
of the side walls on the flow in the case of the flow extended to infinity is
stronger than those in the other cases.

Key words: 
effects of the side walls, steady flow, viscous fluid. 
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9.
OPTIMIZATION OF THE STIFFNESS OF GLUED LAMINATED
TIMBER BEAMS WITH RESPECT TO THE TECHNOLOGY OF
FABRICATION AND CREEP PARAMETERS
Philippe JODIN and Guy PLUVINAGE
Laboratoire de Fiabilité Mécanique
Université de Metz, FRANCE
Vladimir SAPOUNOV
Physics Engineering Institute
Moscow, RUSSIA
The optimization of the quality of glued laminated timber depends on many
parameters which are here reviewed. These parameters have an influence which is
quantified by an influence coefficient which appears in a quality function. The
goal of this work is to estimate the importance of each physical or
technological coefficient on the quality function of a glued laminated timber
beam.

Key words: 
gluelam, mechanical properties, processing, creep, optimization. 
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