Effect of Destabilizing Heating on Go¨rtler Vortices

Experimental investigations of the effect of destabilizing heating on the vortex instability in a laminar boundary-layer flow of air along a concave surface are reported. The ranges of the parameters studied herein are Gr (Grashof number) from 0 to 70 and G (Go¨rtler number) from 0.46 to 9.0. The wavelength of the vortices remains unchanged with heating but the strength of the vortices is enhanced by heating. The amplitude of the vortices increases almost exponentially with the combined parameter (G² + f Gr)^1/2, where f is found to be between 0.3 and 0.4, until the nonlinear effects become important. In the nonlinear region the original sinusoidal wave form of the vortices becomes distorted and they meander in the lateral direction.