Unsteady free convective flow and mass transfer through a porous medium bounded by an infinite vertical limiting surface with constant suction and time-dependent temperature

1983 ◽  
Vol 7 (4) ◽  
pp. 385-389 ◽  
Author(s):  
A. A. Raptis
2014 ◽  
Vol 18 (suppl.2) ◽  
pp. 515-526 ◽  
Author(s):  
Arunachalam Govindarajan ◽  
Ali Chamkha ◽  
Sundarammal Kesavan ◽  
Mohanakrishnan Vidhya

An investigation of unsteady MHD free convective flow and mass transfer during the motion of a viscous incompressible fluid through a porous medium, bounded by an infinite vertical porous surface, in a rotating system is presented. The porous plane surface and the porous medium are assumed to rotate in a solid body rotation. The vertical surface is subjected to uniform constant suction perpendicular to it and the temperature at this surface fluctuates in time about a non-zero constant mean. Analytical expressions for the velocity, temperature and concentration fields are obtained using the perturbation technique. The effects of R (rotation parameter), k0 (permeability parameter), M (Hartmann number) and w (frequency parameter) on the flow characteristics are discussed. It is observed that the primary velocity component decreases with the increase in either of the rotation parameter R, the permeability parameter k0, or the Hartmann number M. It is also noted that the primary skin friction increases whenever there is an increase in the Grashof number Gr or the modified Grashof number Gm. It is clear that the heat transfer coefficient in terms of the Nusselt number decreases in the case of both air and water when there is an increase in the Hartmann number M. It is observed that the magnitude of the secondary velocity profiles increases whenever there is an increase in either of the Grashof number or the modified Grashof number for mass transfer or the permeability of the porous media. Concentration profiles decreases with an increase in the Schmidt number.


1991 ◽  
Vol 181 (2) ◽  
pp. 171-181 ◽  
Author(s):  
T. P. Singh ◽  
A. K. Agrawal ◽  
H. L. Agrawal ◽  
A. Raptis

1970 ◽  
Vol 5 (1) ◽  
pp. 27-36 ◽  
Author(s):  
V Ambethkar

The objective of this work is to study heat and mass transfer in an unsteady MHD free convective flow past an infinite vertical plate with constant suction numerically.  Dimensionless governing equations of the problem have been solved by using finite difference technique. Numerical solutions for temperature, velocity, concentration have been obtained for suitable parameters like Grashoff number, mass Grashoff number, Prandtl number and Schmidt number. Rate of heat transfer and mass transfer are studied. The results obtained are discussed with the help of graphs and tables to observe effect of various parameters concerned in the problem under investigation. Stability and convergence of the finite difference scheme is established. Key words: MHD, unsteady, constant suction, finite difference technique, Heat and mass transfer. doi:10.3329/jname.v5i1.1785 Journal of Naval Architecture and Marine Engineering Vol. 5, No. 1 (June, 2008) 27-36


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