We introduce a passive receptive channel in an open rectangular cavity to reduce the acoustic tones generated due to coherent shear layer impingement. The rectangular channel is placed at the trailing edge of the cavity. It is easy to implement and is a passive controller that responds to the flow for a wide range of operating conditions. Different orientation for the rectangular channel has been numerically tested at Mach 0.1, 0.3 and 0.5. Numerical results using unsteady three-dimensional large eddy simulation showed that the channel reduced the coherence of the shear layer which caused the acoustic suppression resulting in a reduction of the sound pressure levels for all three Mach numbers tested. Specifically, the acoustic suppression of 10 dB was obtained for Mach 0.3 flow with a 71.56° channel. The channel can be useful in noise reduction for various applications including weapons bay, landing gear and branched piping systems.
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