Suppression effect of jet flow on aerodynamic noise of cavity

The structure of cavity flow field with high Mach number is very complex, in which pressure and velocity pulsate seriously, leading a fierce noise about almost 170 dB. The noise is posing a great threaten to the safety of the missile in the cavity and the structure of the cavity. This paper simulates the changes of the aeroacoustics in the M219 cavity (length to high aspect ratio L/D=5) in which the jet flow from the engine is used and make a study on the flow characteristic, flow field structure and the sound mechanism in the cavity by applying the Scale-Adaptive Simulation (SAS) model developing from two equation SST turbulent model and aerodynamic acoustic frequency theory (FW-H integration formulation). On the basis of this, the situation of jet flow which can be realized in the engineering is determined after comparing and analyzing the suppression effect on the cavity noise of the different jet situation. Then the suppression effect on the cavity noise of different jet state is compared and analyzed (different jet flow quality, temperature). The conclusion can be drawn that in transonic condition, the different jet condition has a different suppression effect on the the cavity noise. With the increasing of the jet flow quality and jet temperature, the noise suppression effect is more obvious.