Effects of blowing on delta wing vortices during dynamic pitching

An experimental investigation was conducted in a water tunnel to identify the effects of apex blowing on two delta wing models undergoing constant pitch-rate motion. One wing was of 60-deg sweep and the other was of 76-deg sweep. Flow visualization methods were utilized to determine vortex burst locations for a range of pitchup and pitch-down rates, apex jet strengths, and blowing directions. Results indicate, individually, that blowing direction on the 60-deg wing and blowing rate on the 76-deg wing have the greatest effect on vortex behavior under both static and dynamic pitch-up conditions. Vortex improvements, for any blowing direction or rate examined, are most dramatic during dynamic pitch-down conditions. In this case, the use of blowing resulted in the reformation of unburst vortices with significant length.