Archive issue - vol.2 No.3



   No.   Author(s) - Title
Pages

   1.
 

 Rahaman K. -- Unsteady, laminar viscoelastic flows through rectangular ducts
 

303-318
 

   2.
 

 Çarpinlioglu Melda Ö. -- Development of a quasi 3-D boundary layer
 

319-340
 

   3.
 

 Gorla R.S.R., Ramalingam K. and Adluri I. -- Magnetohydrodynamic disk braking
 

341-351
 

   4.
 

 Liu R.H. and Yuan H. -- Nonlinear bending of corrugated annular plate with large boundary corrugation
 

353-367
 

   5.
 

 Takhar H.S., Agarwal R.S. and Bhargava R. -- The squeezing of a micropolar fluid between two plates
 

369-377
 

   6.
 

 Chen F.K. and Chao M.T. -- Deformation mechanics of the springback in U-bending
 

379-403
 

   7.
 

 Mansour M.A. -- Forced convection -radiation interaction heat transfer in boundary-layer over a flat plate submersed in a porous medium
 

405-413
 

   8.
 

 Erdogan M.N. -- Effect of the side walls on the flow over a moving plane wall
 

415-432
 

   9.
 

 Jodin P., Pluvinage G. and Sapounov V. -- Optimization of the stiffness of glued laminated timber beams with respect to the technology of fabrication and creep parameters
 

433-443
 

 



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 non-Newtonian fluids. Upper-convected 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, upper-convected Maxwell, rectangular ducts.

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2.

DEVELOPMENT OF A QUASI 3-D 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 3-D boundary layer on a swept wing; the boundary layer on the test plate was called a quasi 3-D 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, Rcf and Rx=1*105 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 3-D 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 B0 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

Ren-Huai 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
Roorkee-247667, 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 double-shooting 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 U-BENDING

Fuh-Kuo CHEN and Ming-Teh CHAO

Department of Mechanical Engineering
National Taiwan University
Taipei, Taiwan, R.O.C.

     The deformation mechanics of the springback occurring in the U-bending was investigated in the present study. A theoretical model was first developed to analyze the moment-curvature 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 double-bend 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 double-bend technique, is applied.

Key words:

springback, U-bending, theoretical model, finite element method, double-bend.

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7.

FORCED CONVECTION -RADIATION INTERACTION
HEAT TRANSFER IN BOUNDARY-LAYER 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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