Transient boundary layer flow of viscous compressible fluid past a heated sphere with the effect of Mach number

A two-dimensional transient boundary layer flow of an unsteady, viscous, compressible fluid past a heated sphere with the effect of Mach number is considered. The governing boundary layer equations are reduced to nonsimilar form, and these are solved numerically by three methods, namely, the finite difference method for all time regime, perturbation solutions for small time regime, and the asymptotic solutions for large time regime. Comparisons of the results show a good agreement between the above mentioned methods. Effects of various practical values of the surface temperature parameter, a and the Mach number, M-0 on the local shear stress, the rate of heat transfer, streamlines and isoenthalpies are shown graphically. Further, it is observed that increase in the value of Mach number, M-0, leads to an increase in the local shear stress and the rate of heat transfer; whereas opposite effect is found in case of local shear stress once the point of separation occured. On the other hand size of the vortex found to be decreased with an increase in Mach number. (C) 2019 Published by Elsevier Masson SAS.