Abstract
The mixed laminar boundary layer flow and heat transfer on a permeable stretched surface moving with prescribed skin friction are studied. Three major cases, which correspond to complete similarity solutions, are considered. The cases are combinations of power law indices n and m representing temperature and skin friction distributions, respectively. The first case (n=0, m=0.5) corresponds to isothermal stretched surface with skin friction at the surface scales as x(1/4). The second case (n=1, m=1) is a linear temperature and skin friction distribution along the vertical stretched surface. The third case (n=-1, m=0) represents inverse temperature variation along the surface with prescribed skin friction of the order of x(-1/2). Similarity solutions are obtained for the surface stretched in a stagnant air with Prandtl number=0.72. The effect of suction/injection velocity (f(w)) and the buoyancy parameter (lambda) is studied in detail. The results show that the heat transfer coefficient along the surface is enhanced for assisting flow (lambda>0) at any value of f(w) for the first and second cases, while it is reduced for the third case. However, the opposite is true for the opposing flow (lambda<0). Furthermore, suction enhances the heat transfer coefficient, whereas injection degrades it at any fixed for the first and second prescribed skin friction boundary conditions, and the opposite is true for the third case.