The competing effects of wall transpiration and stretching on Homann stagnation-point flow

The simultaneous effects of normal transpiration through a radially stretching porous plate beneath Homann stagnation-point flow are considered. The exact similarity reduction of the Navier-Stokes equations depends on the stretching parameter λ and the transpiration parameter μ. Dual solutions are found over a limited range λc<λ<−1 in the case of suction (μ>0) but unique solutions exist for blowing (μ<0). It is shown that the range of dual solutions increases with μ, but a self-similar stability analysis reveals that the lower solution branches are unstable while upper solution branches are stable.