Experimental investigation of two-stream mixing flow with multiple tabs

Vortex-generating tabs arranged in the form of an array have been examined experimentally using a laser Doppler anemometer in a two-stream mixing flow situation. The vortex-generating tabs are the, "delta tabs:" i.e., triangu lar-shaped protrusions into the how attached to the trailing edge of the sp litter plate. A velocity ratio of 2:1 (upper and lower) between the two cof lowing streams was used. Three arrangements for the tabs are investigated. Case 1 has all of the tabs located on the high-speed side. The tabs are loc ated alternatively on either side of the splitter plate for case 2, and fin ally, case 3 is similar to case 2,but the tab on the low-speed side is tilt ed upstream (i.e.,; similar to a delta-wing vortex generator). Mutual cance llation between streamwise vortices rotating in the opposite sense was obse rved in case 1, whereas in case 2 the merging of streamwise vortices rotati ng in the same sense had delayed the decay of the streamwise vorticity. For case 3 the upstream tilted tab appeared to have generated relatively weak streamwise vortices so that they were canceled off by the vortices generate d on the high-speed side near the trailing edge; Finally, the turbulence ch aracteristics for each case are presented and discussed.