Unsteady swirling flow of a compressible fluid over an infinite disk with a magnetic field or suction

Abstract

The laminar boundary layer over a fixed infinite disk induced by a time-dependent vortex flow of compressible fluid is considered. The free-stream velocity has been taken as tangential and varies as a power of radius, i.e.ν_∞r^-nφ(τ) where φ(τ) is an arbitrary function of time t. Several free-stream velocity distributions have been examined. The effect of a magnetic field and suction are also included in the analysis. The solutions are studied for various values of n in the range (-1≤n≤1) and also for several values of disk-to-fluid temperature ratio. The oscillations in the velocity profiles decrease with time in the absence of a magnetic field and suction for an accelerating free stream. Heat transfer at the wall is affected slightly by the time variation of free-stream velocity. Solution is possible only for a certain range of n unless a magnetic field or suction is applied.