An experimental investigation of two-stream mixing flow with a single delta tab

摘要

A single inverted delta tab attached to the trailing edge of a splitter plate in a two-stream mixing layer has been examined ex- perimentally using a three-component laser-Doppler anemometer. Detailed mean flow and turbulence measurements were obtained at a belocity ratio of 2:1 between the two co-flowing streams. The results showned that, when the tab was tilted to the high-speed side, streamwise vortices generated and the subsequent mixing were stronger and more intense than when tilting it to the low-speed side. Their differences in the steramwise vorticity generation mechanism were explained in relation to the tab theory proposed by Bohl And foss (Near exit plane effects caused by primary and primary-plus-secondary tabs, AIAA Journal 37(2) (1999) 192-201). The Strength of streamwise vorticity appeared to have a direct correlation with the level of turbulence generated in the cross-stream Directions. Attempts were also made to quantify the effect of each (streamwise vorticity) production term in the streamwise vorticity Transport equation.