Abstract
The mixing promoting efficiency of a limiting corrugated tab, located across a diameter of Mach 1.73 convergent-divergent circular nozzle exit, has been studied experimentally. With uncorrugated tab the core length reduction achieved is just 42%, but for the tab with semi-circular corrugations, the reduction in core length is as high as 98%, at underexpanded level corresponding to NPR 6. The corrugation geometries have a strong effect on the mixing promoting capability of the tab. The mixing promotion is found to be the best when there is no pressure gradient at the nozzle exit. Among the corrugated tabs studied, the tab with semi-circular corrugations is found to be the best mixing promoter. The core length reduction achieved for the correctly expanded jet with the tab with semi-circular corrugations is almost 98%, whereas the reduction caused by the tabs with triangular and rectangular corrugations are 96% and 92%, respectively. In addition to reducing the core length the corrugated tabs were found to be weakening the waves and shortening the shock cells length.
©[2013] by Walter de Gruyter Berlin Boston
