Begell House Inc.
International Journal of Fluid Mechanics Research
FMR
2152-5102
36
4
2009
Unsteady Hydrodynamic Flow Induced by a Porous Plate in a Rotating System
289-299
S.
Das
Department of Applied Mathematics with Oceanology and Computer Programming, Vidyasagar University, Midnapore 721 102, West Bengal, India
Mrinmoy
Guria
Department of Applied Mathematics with Oceanology and Computer Programming, Vidyasagar University, Midnapore - 721102, West Bengal, India
Rabindra N.
Jana
Department of Applied Mathematics, Vidyasagar University, Midnapore-721 102, West Bengal, India
The unsteady flow of viscous incompressible fluid bounded by an infinite flat porous plate in a rotating fluid is considered where both the plate and the fluid rotate in unison with uniform angular velocity Ω about an axis normal to the plate. Initially (t' = 0) the fluid at infinity moves with uniform velocity U0 in the direction of the flow. At time t' > 0, the plate suddenly moves with uniform velocity U0 in the direction of the flow. The velocity field and the shear stress components at the plate are found exactly by using Laplace transform technique. The solutions are also obtained for small and large times.
Free Convection Flow Past an Isothermal, Adiabatic and Plane Plume Inclined Stretching Surfaces in a Porous Medium
300-318
M. A.
Mansour
Department of Mathematics, Assuit University, Faculty of Science, Assuit, Egypt
N. F.
El-Anssary
Department of Mathematics, Faculty of Science, South Valley University, Qena, Egypt
Abdelraheem M.
Aly
Department of Mathematics, Faculty of Science, Abha, King Khalid University, Saudi Arabia;
Department of Mathematics, Faculty of Science, South Valley University, Qena, Egypt
An analysis is presented to investigate the effects of chemical reaction, heat generation, the Soret and Dufour numbers on free convective heat and mass transfer of a viscous incompressible electrically conducting fluid on an inclined stretching surface in a porous medium. Three conditions are considered, namely, the isothermal surface, plane plume, flow generated by horizontal energy source and vertical adiabatic surface. By the similarity transformation, governing partial differential equations have been transformed into a system of ordinary differential equations, which are solved numerically using the fourth-order Runge - Kutta scheme with shooting method. The obtained results show that the flow field is appreciably influenced by presence of chemical reaction, permeability parameter, Dufour number and the angle of an inclined surface.
Study on Pressure Drop and Center Line Velocity Distribution Across Cosine Shaped Stenotic Model
319-342
Moloy Kumar
Banerjee
Department of Mechanical Engineering, Future Institute of Engineering and Management Kolkata, India
Ranjan
Ganguly
Department of Power Engineering, Jadavpur University Kolkata 700098, India
Amitava
Datta
Power Engineering Department, Jadavpur University, Salt Lake Campus, Kolkata 700098, India
Arterial stenosis refers to the swelling of the endothelial wall due to plaque deposition and the associated disease is known as atherosclerosis. A stenosed artery reduces the maximum flow of blood through it by putting more resistance to the flow. The pressure of blood in a coronary artery is considered to be one of the important contributors for the formation and progression of atherosclerosis. Therefore, in this paper, the impact of flow Reynolds number(Re) and degree of stenosis (S) on wall pressure near the stenosis in a part of coronary artery is studied considering laminar flow and modeling blood as both Newtonian and non-Newtonian fluid. The two-dimensional steady differential equations for conservation of mass and momentum is solved by finite difference method through stenosed arteris having mild (S = 25 %) to severe (S = 65 %) occlusions and under different regimes of flow Reynolds numbers ranging from 50 to 400. From the study, it is revealed that for all the cases a sharp variation in dimensionless wall pressure is observed near the zone of restriction. The peak centerline velocity in the stenosed region is more sensitive to a change in the degree of occlusion rather than change in the flow Re. From the study it is also revealed that at high Re regime the irreversible pressure loss coefficient (CI) becomes insensitive to Re values and can be approximated to be a function of S only.
Computation of Viscous Flow Field in a Tapered Artery with an Overlapping Constriction
343-356
Swati
Mukhopadhyay
Department of Mathematics, The University of Burdwan, India
C.
Midya
Department of Mathematics, S. S. College, Murshidabad, W. B., India
Gorachand C.
Layek
Department of Mathematics, University of Burdwan Burdwan, West Bengal, India
This paper presents the detailed numerical study of blood flow through models of stenotic and tapered arterial segments. The arterial model is treated to be two-dimensional and axisymmetric. A tapered artery with an overlapping stenosis is considered here in order to update the resemblance to the in vivo situation. The blood flowing through the artery is treated to be Newtonian. To compute the flow characteristics, such as wall pressure, flow velocity, and wall shear stress, the unsteady Navier-Stokes equations are solved numerically by using the marker and cell method. Finally, the numerical illustrations presented in this paper provide an effective measure to estimate the combined influence of tapering and stenosis on the flow characteristics.
Free Convective Flow of Magneto-Polar Fluid Past a Porous Vertical Wall Embedded in Non-Homogeneous Porous Medium in Slip Flow Regime
357-374
Atul Kumar
Singh
Department of Mathematics, V. S. S. D. College, Kanpur 208002, India
This paper deals with a study of two-dimensional unsteady convective flow of an incompressible, electrically conducting, magneto-polar fluid through a vertical porous wall in slip flow regime under the action of uniform transverse magnetic field fixed to the fluid. In the energy equation the viscous dissipation, heat sink and Ohmic heating are taken into account. Multi-perturbation technique is applied to obtain the expressions for velocity and temperature distributions. Expressions for skin-friction and Nusselt numbers are also obtained. The results are discussed graphically for different values of the parameters entered into the equations of the problem.
Flow Characteristics of Double Offset S-Shaped Circular Diffusing Duct
375-390
Rajesh K.
Singh
Department of Applied Mechanics, IIT Delhi, New Delhi-110016
S. N.
Singh
Department of Applied Mechanics, IIT Delhi Hauz Khas, New Delhi, India
V.
Seshadri
Department of Applied Mechanics, IIT Delhi Hauz Khas, New Delhi, India
Effect of Reynolds number and horizontal offset for a fixed vertical offset has been investigated for a double offset S-shaped circular diffusing duct using a CFD code FLUENT. The investigations have been carried out for a fixed geometry using different turbulence models and it is observed that the RNG turbulence model gives the closest matching with experimental results. Investigations have shown that at high Reynolds numbers (≈ 106), there is no effect of Reynolds number on the performance of the diffuser. Secondary flow distribution has shown the formation of two pairs of contra rotating vortices at the exit plane and beyond. The core of the flow moves along the diagonal plane which is inclined to vertical axis at an angle determined by the magnitude of horizontal offset i. e. 15°/15° offset gives an angle of 30° whereas 30°/30° offset gives an angle of approximately 60°.