Begell House
Journal of Porous Media
Journal of Porous Media
1091-028X
13
9
2010
KELVIN-HELMHOLTZ AND RAYLEIGH-TAYLOR INSTABILITY OF STREAMING FLUIDS WITH SUSPENDED DUST PARTICLES FLOWING THROUGH POROUS MEDIA
The linear Kelvin-Helmholtz (K-H) instability and Rayleigh-Taylor (R-T) instability of two superposed streaming incompressible fluids flowing through porous medium is investigated considering the combined effects of suspended dust particles and surface tension. The linearized hydrodynamic equations are solved and the general dispersion relation is obtained using the normal mode analysis by applying the appropriate boundary conditions. We find that the dispersion relation is modified due to the simultaneous presence of porosity, suspended dust particles, permeability, and surface tension. The conditions of K-H instability as well as R-T instability are obtained for the porous media with suspended dust particles, permeability, dynamic viscosity, and surface tension. It is observed that the condition of K-H instability depends upon medium porosity, suspended dust particles, viscosity, permeability, and surface tension, but the condition of R-T instability depends on surface tension only. From the graphical interpretation we find that the density of
suspended dust particles and medium porosity has a stabilization effect on the growth rate of unstable K-H mode. The
dynamic viscosity, medium porosity, surface tension, and density of suspended dust particles have a stabilizing effect
while Atwood number causes destabilization on the growth rate of unstable R-T mode.
R. P.
Prajapati
School of Studies in Physics, Vikram University, Ujjain-456010, M. P., India
Rajendra K.
Chhajlani
School of Studies in Physics, Vikram University Ujjain (M.P.)-456010, India
765-777
MAGNETOGRAVITATIONAL INSTABILITY OF THERMALLY CONDUCTING ROTATING VISCOELASTIC FLUID WITH HALL CURRENT IN BRINKMAN POROUS MEDIUM
Magnetohydrodynamic instability of a self-gravitating, thermally finitely conducting, Rivlin-Ericksen viscoelastic fluid rotating in a general direction through a Brinkman porous medium in the presence of Hall current and vertical magnetic field was investigated. A general dispersion relation has been derived through relevant linearized perturbation equations. The cases when the axes of rotation were parallel or perpendicular to the direction of magnetic field were investigated separately for both longitudinal and transverse wave propagations. It has been observed that a condition of instability is determined by Jean's criterion in its modified form. The effects of various parameters on the stability of this system are studied numerically, and they showed that different behaviors depend on the corresponding case, as summarized in the Conclusions section.
Mohamed F.
El-Sayed
Department of Mathematics, Faculty of Education, Ain Shams University, Heliopolis (Roxy), Cairo, Egypt
R. A.
Mohamed
Department of Physics, Faculty of Education, Ain Shams University, Heliopolis, Roxy, Cairo; Department of Mathematics, Faculty of Sciences, South Valley University, Qena, Egypt
779-798
NON-DARCY MIXED CONVECTION IN A FLUID SATURATED SQUARE POROUS ENCLOSURE UNDER SUCTION EFFECT: PART II
In Part I [13] of the study the authors presented a detailed investigation on the non-Darcian mixed convection process with inlet/outlet windows at bottom/top walls. Here the investigation is continued with an exchange in inlet/outlet locations. The dramatic change in the physics of the convection process, i.e., in the flow and temperature distributions brought in by such an interchange of suction/injection locations, are traced through local/cumulative/global heat fluxes, streamlines, and isotherms for different values of parameters like Grashof number (Gr*), Rayleigh number (Ra), suction/injection flow velocity (a), and inlet/outlet window width (D/H).
Somanchi V S S N V G
Krishna Murthy
Department of Applied Mathematics, Defence Institute of Advanced Technology, Gririnagar, Pune 411025, India
B. V. Rathish
Kumar
Department of Mathematics and Statistics, Indian Institute of Technology, India
Vivek
Sangwan
Department of Mathematics and Statistics, Indian Institute of Technology, Kanpur 208016, India
Mohit
Nigam
Department of Mathematics and Statistics, Indian Institute of Technology, Kanpur 208016, India
P.
Chandara
Department of Mathematics and Statistics, Indian Institute of Technology, Kanpur, Kanpur- 208016, India
799-805
CONSTITUTIVE MODELING FOR PLASTICITY OF METAL POWDERS DURING COMPACTION
In works dealing with the plastic behavior of metal powders, the material density or relative density has been a major
isotropic hardening parameter. In this work, in a more realistic modeling, the equivalent plastic strain of the porous material, in addition to the relative density, is considered as an isotropic hardening parameter. Using an associated flow rule, the plastic deformation rate is derived and then, by fitting some experimental data obtained from hydrostatic compaction and simple compression tests on aluminum powder, the model parameters are identified for this powder. The identified model is finally verified by some other experimental results obtained from closed-die compaction tests. This last step also confirms that the model could take into account the powder characteristics via loose relative density.
Gholamreza
Aryanpour
Department of Materials Engineering, Isfahan University of Technology, 84156 Isfahan, Iran
Masoud
Farzaneh
CIGELE/INGIVRE, University of Québec at Chicoutimi, 555 Boulevard de l'Université, Chicoutimi, Québec G7H 2B1, Canada
807-823
HEAT AND MASS-TRANSFER FLOWPAST A VERTICAL POROUSWALL WITH VARIABLE HEAT AND MASS FLUX
The present paper deals with an analysis of mixed convection heat and mass-transfer flow of an incompressible, viscous
fluid along an infinite porous vertical wall embedded in a homogeneous porous medium with variable suction velocity,
heat, and mass flux. The Laplace transform technique is performed to obtain the solution in terms of repeated integrals of complementary error functions. The numerical values of surface shear stress, wall temperature, and concentration functions for different values of Prandtl number, Schmidt number, suction velocity parameter, and permeability parameter are reported in tables while the velocity, temperature, and concentration profiles are shown in figures. The results obtained are discussed for the case of most common interest, viz. cooling of the porous wall.
827-837
ROTATING FLOWOF A GENERALIZED BURGERS' FLUID WITH SLIP CONDITION
The slip effects on the magnetohydrodynamic (MHD) and rotating flow between two rigid plates is investigated. An
incompressible generalized Burgers' fluid fills the porous space between two boundaries. The flow is engendered by the
oscillation of an upper plate in its own plane. Mathematical formulation is presented by employing a modified Darcy's
law. An exact solution is constructed and analyzed for various pertinent parameters.
Saher
Najam
Department of Mathematics, Quaid-i-Azam University 45320, Islamabad 44000, Pakistan
S.
Asghar
Department of Mathematical Sciences, COMSATS Institute of Information Technology, 30 Islamabad, Pakistan
839-845
HEAT-TRANSFER ANALYSIS OF MHD FLOWDUE TO A PERMEABLE SHRINKING SHEET EMBEDDED IN A POROUS MEDIUM WITH INTERNAL HEAT GENERATION
The Adomian decomposition method with Padé approximants is employed in this study as a simple, non-perturbative
alternative to solve the magnetohydrodynamic (MHD) boundary-layer flow due to a permeable shrinking sheet embedded
in a porous medium. The effects of internal heat generation in the flow are considered. The effects of suction on skin
friction and heat-transfer rate at different Padé approximants are tabulated, while the effects of various parameters on the flow velocity and temperature are discussed and presented graphically.
Noor Fadiya Mohd
Noor
Faculty of Applied Sciences & Mathematics, Universiti Industri Selangor, 45600 Berjuntai Bestari Selangor, Malaysia
Muhaimin
Ismoen
Science Studies Center, Universiti Tun Hussein Onn Malaysia, 86400 Parit Raja, Batu Pahat, Johor, Malaysia
Ishak
Hashim
School of Mathematical Sciences; Solar Energy Research Institute, Universiti Kebangsaan Malaysia, 43600 UKM Bangi Selangor, Malaysia
847-854