Investigation of Spectral Characteristics by Passive Control Methods Past a Supersonic Cavity

Abstract

Numerical investigations of the leading-edge sawtooth spoiler and slanted aft wall were performed to explore the mechanisms of the suppression of pressure fluctuations in an open-type cavity flow, focusing on the pressure fluctuation spectra and their spatial distributions. The rectangular cavity has a length-to-depth ratio of six, and the freestream Mach number is 1.5. Improved delayed detached-eddy simulation was used to predict the unsteady cavity flows and pressure fluctuations. Both control methods exhibited effectiveness in pressure fluctuation suppression, but their respective mechanisms are quite different. It was observed that the leading-edge sawtooth spoiler lifts the shear layer and reduces its interaction with the aft wall. The energy distribution of Rossiter modes changes significantly, which indicates that the pressure fluctuation feedback loop inside the cavity has changed. However, the slanted aft wall merely alters the cavity flowfield. Unlike the leading-edge method, the Rossiter mode distribution and the feedback mechanism remain unchanged. The slanted aft wall mainly suppresses the upstream-traveling perturbation generated by the cavity trailing edge but has little influence on the downstream-traveling perturbation.