Experimental Study of the Suppression of Wing-Body Rock by Spanwise Blowing

The method of symmetrical spanwise blowing was used to suppress the wing-body rock of a typical canard-configuration model in free-to-roll tests. The experimental results showed that the rock was successfully suppressed by symmetrical spanwise blowing when the pitch angle was between thirty degrees and thirty-four degrees. However, this kind of blowing failed to suppress the non-commanded motion once pitch angle exceeded thirty-four degrees. To analyze the mechanism under this phenomenon, surface-pressure measurements and Inv tests were carried out. The reason for the successful suppression was inferred as the success of the delaying of windward vortex breakdown at a small sideslip angle, while the failed results at larger pitch angles were due to the fact that the blowing cannot delay the windward breakdown anymore under very small sideslip.