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

A single inverted delta tab attached to the trailing edge of a splitter pla te in a two-stream mixing layer has been examined experimentally using a th ree-component laser-Doppler anemometer. Detailed mean flow and turbulence m easurements were obtained at a velocity ratio of 2:1 between the two co-flo wing streams. The results showed that, when the tab was tilted to the high- speed side, streamwise vortices generated and the subsequent mixing were st ronger and more intense than when tilting it to the low-speed side. Their d ifferences in the streamwise vorticity generation mechanism were explained in relation to the tab theory proposed by Bohl and Foss (Near exit plane ef fects caused by primary and primary-plus-secondary tabs, AIAA Journal 37(2) (1999) 192-201). The strength of streamwise vorticity appeared to have a d irect correlation with the level of turbulence generated in the cross-strea m directions. Attempts were also made to quantify the effect of each (strea mwise vorticity) production term in the streamwise vorticity transport equa tion. (C) 2001 Elsevier Science Inc. All rights reserved.