Unsteady MHD forced flow due to a point sink

An analysis is performed to study the unsteady laminar incompressible bound ary-layer flow of an electrically conducting fluid in a cone due to a point sink with an applied magnetic field. The unsteadiness in the flow is consi dered for two types of motion, viz. the motion arising due to the free stre am velocity varying continuously with time and the transient motion occurri ng due to an impulsive change either in the strength of the point sink or i n the wall temperature. The partial differential equations governing the fl ow have been solved numerically using an implicit finite-difference scheme in combination with the quasilinearization technique. The magnetic field in creases the skin friction but reduces heat transfer. The heat transfer and temperature field are strongly influenced by the viscous dissipation and Pr andtl number. The velocity field is more affected at the early stage of the transient motion, caused by an impulsive change in the strength of the poi nt sink, as compared to the temperature field. When the transient motion is caused by a sudden change in the wall temperature, both skin friction and heat transfer take more time to reach a new steady state. The transient nat ure of the flow and heat transfer is active for a short time in the case of suction and for a long time in the case of injection. The viscous dissipat ion prolongs the transient behavior of the flow.