The influence of suspended particles on the onset of B› convection is studied in the presence of a vertical magnetic field. The principle of exchange of stabilities is satisfied. The influence of suspended particles is to destabilize the layer whereas the effect of magnetic field is stabilizing. The effect of a uniform rotation is also studied and is found to have a stabilizing influence in the presence of suspended particles on the B› conveetion. IntroduetionThe problem of the onset of B› conveetion (thermal iiastability), under varying assumptions of hydrodynamics and hydromagnetics, has been discussed in a treatise by CHAr~DRAS~KHAR [2].Cr~ANDRA [1] found that the instability depended on the depth of the layer. A B› cellular convection with fluid descending at the cell centre was observed when the predieted gradients were imposed, if the layer depth is more than 10 mm. But if the depth of the layer was less than 7 mm, convection occurred at much lower gradients than predicted and appeared as irregular strips of elongated cells with fluid rising at the centre. This motion was named 'columnar instability' by CHAtarRA [1] and the phenomenon was observed by hito in ah air layer. Thus there is a contradiction between the theory and the experiment. ScAr~Lo~ and S~CZL [3] eonsidered the effect of particle mass and heat capacity on the onset of B› convection and found that the eritical Rayleigh number was redueed solely because the heat capacity of the pure gas was supplemented by that of the particles. The effect of suspended particles was found to destabilize the layer.The present paper deals with the effect of suspended particles on the onset of B› convection in the presente of a uniform vertical magnetic field. The gas is assumed to be infinitely conducting and the particles to be non-conducting. The effect of a uniform rotation on the onset of B› convection in the presence of suspended particles is also studied.

No abstract

An analysis is presented for lsminar radial flow due to a linear source between two parallel stationary infinite disks. The source strength varŸ according to Q --Qo (v_~~) (t > 0) % and the solution is in the form of ah infinite series in terms of a reduced Reynolds number [ ~/( r ~ ( vt R~ --~ . .--.--~ |~-~-,/|-~-~. The results ate valid for small values of R~ and t|----..-~-~[" The effect of the parameter R* on the radial velocity distribution, pressure distribution, shear suress at the upper disk at different times is diseussed. Nomenelature h = hall distance between disks r = radial coordinate r r ~---= dimensionless radial eoordinate h z --~ axial coordinate z z =-= dimensionless axial coordinate h t ----time vt r

No abstract

No abstract

No abstract

Nomenelature T ----temperature ~-~ specific heat at constant pressure hP~-~ hall distanee between paraHel p|ates ---~ therma] conductivity t ---~ time u -~--ve]ocity component in x-direction u ~-~ mean ve]ocity of average ve]ocity x, y -~ eartesian coordinates (x-flow direetion, y-distanee from channe] centreHne) ~-~ fluid density -~--kinematie coefficient of viscosity hu R --~ Reyno]ds number ---~-P = Prandtl number ~__Qcpv x Te, TI, T 2 ~ known constant temperatures 1. IntroduetionThe study of unsteady forced convection heat transfer in tubes and ducts has recent]y become of grcater importancc in connection with the control of modern high performance heat transfer devices. Litcrature on thermal transicnt problems is ]imited but increasing. In so]utions of the prob]ems of transient forced convection in laminar flow it has usually becn assumed that the inlet temperaturc of the fluid is constant across the flow with a specificd timewise variation of wall temperature, wall heat flux or internal heat generation.In the present paper an exact solution of the transient forced convection cncrgy cquation of a viscous incomprcssiblc fluid with fully dcvclopcd flow in .4esa Physiea Ar Scientiarum Hunsaricae 40, 1976

No abstract