An aeroacoustic mechanism to explain universal behavior in hypersonic wake flow oscillations

Abstract: Recent experimental studies reveal that the near-wake region of a circular cylinder at hypersonic Mach numbers exhibits self-sustained flow oscillations. The oscillation frequency was found to have a universal behavior. Experimental observations suggest an aeroacoustic feedback loop to be the driving mechanism of oscillations. An analytical aeroacoustic model which predicts the experimentally observed frequencies and explains the universal behavior is presented here. The model provides physical insights and informs of flow regimes where deviations from universal behavior are to be expected.