THE EFFECTS OF BLOWING AND SUCTION ON FREE-CONVECTION BOUNDARY-LAYERS ON VERTICAL SURFACES WITH PRESCRIBED HEAT-FLUX

The effects that blowing and suction have on the free convection boundary layer on a vertical surface with a given surface heat flux are considered. Similarity equations are derived first, their solution being dependent on the wall flux exponent n and a dimensionless transpiration parameter gamma, (as well as on the Prandtl number). The range of existence of solutions is considered, with it being shown that solutions exist only for n > -1 for blowing, whereas they exist for all n > n0 for suction, where n0 < -1 and depends on gamma. The solutions for strong suction and blowing are derived. In the latter case the asymptotic structure is found to be different for n in the three ranges -1 < n < -1/4 , -1/4 < n < 7/2 , n > 7/2. Results are then obtained for the non-similarity problem of constant heat flux with a constant transpiration velocity. Solutions valid for large distances from the leading edge for both suction and blowing are derived.