Effect of a Trailing-Edge Jet on Fin Buffeting

Effect of a trailing-edge jet on the intera ction of a leading-edge vortex with an and resultin n buffeting was investig atedinwater-tunnel aswell aswind-tunnelex periments. Flow visualizationshowed that n-induced vortex breakdown can be delayed into the wake even for the head-on collision of the leading -edge vortex with then.Hence it was demonstrated that the adverse pressure gradient caused by the presence of then could be overcome with a deected trailing-edge jet. Delay of vortex brea kdown into the wake even for relatively small values of jet velocity ratio is possible for de ected jets, whereas the effectiveness of the jet with no de ection is very limited. Buffeting response of a exiblen in wind-tunnel experiments showed that there was considerable delay of the onset of buffeting to higher angles of attack with increasing jet momentum for ¯ = 30 a nd 45 deg. Depending on the location with respect to the leading-edgevo rtex, it was possibleto shift the buffeting envelope as much as12 degin incidence of the wing. Experiments with varying wing sweep angle showed that jet blowing was as effective in ttenuating n buffeting for less slender wings. Wind-tunnelexperiments also showed that the nozzle geometry is very important and causes very different buffeting envelopes for the same momentum coefcient.