DES of a cavity with spoiler

Abstract

Experimental data from QinetiQ shows the addition of a saw tooth spoiler at the leading edge of the M219 cavity results in a reduction in edge tone resonances by as much as 13dB compared to the clean cavity. In an effort to predict this and understand the underlying mechanism, a detached eddy simulation has been performed for the clean cavity and cavity with spoiler using FLUENT 6.2. Comparison with experiment indicates that the tone amelioration can be reproduced reasonably well. DES also reveals that the spoiler causes the shear layer over the cavity to rise during the first fifth of the cavity length with consequent greater interaction with the region aft of the cavity trailing edge. The teeth appear to have no lasting impact on the flow and it is thought that the displacement effect alone accounts for the tone amelioration. © 2008 Springer-Verlag Berlin Heidelberg.