On the diffusion of species in similar boundary layers with continuously varying properties

Abstract

The solutions derived by Freeman and Simpkins for the diffusion equation in an incompressible chemically frozen boundary-layer flow are extended to include variations in surface and fluid properties by a suitable change of variable. In a worked example for the flat plate case, a comparison is made with the exact series solution due to Inger and the local similarity approximation. For large values of the streamwise co-ordinate the local similarity approximation is shown to be identical to the first-order term of the asymptotic expansions derived herein.