Skin friction and heat transfer in power-law fluid laminar boundary layer along a moving surface

Abstract

Analytical and numerical solutions are presented for momentum and energy laminar boundary layer along a moving plate in power-law fluids utilizing a similarity transformation and shooting technique. The results indicate that for a given power-law exponent n (0<n⩽1) or velocity ratio parameter ξ, the skin friction σ decreases with the increasing in ξ or n. The shear force decreases with the increasing in dimensionless tangential velocity t. When Prandtl number N Pr=1, the dimensionless temperature w( t) is a linear function of t, and the viscous boundary layer is similar to that of thermal boundary layer. In particular, w( t)= t if ξ=0, i.e., the velocity distribution in viscous boundary layer has the same pattern as the temperature distribution in the thermal boundary and δ= δ T. For N Pr⩾1, the increase of viscous diffusion is larger than that of thermal diffusion with the increasing in N Pr, and δ T( t)< δ( t). The thermal diffusion ratio increases with the increasing in n (0<n⩽1) and ξ.