INFLUENCE OF FORCED PERTURBATIONS IN THE STAGNATION REGION ON GORTLER INSTABILITY

摘要

The growth of forced perturbations generated by a wire grid in a concave boundary layer at supercritical Gortler numbers is experimentally investigated. Under certain conditions(sufficiently high wire Reynolds numbers),two pairs of Gortler vortices, instead of the single pair seen in previous experiments(Ajakh,a.,Kestoras,M.D.,Peerhossaini,H.,and Bahri,F.,"An Experimental Study of Gortler vortices, "Proceedings of the Annual Conference of the French Society of Heat Transfer,Elsevier,Paris,1995,pp.272-277),have been observed in the concave boundary layer behind each triggering wire. Two generation mechanisms are examined for these two pairs of vortices associated with Benard-Karman streets and leading-edge vortices.