High-intensity sound absorption at an orifice with bias flow

The high-intensity sound absorption at an orifice with bias flow was discussed using a discrete vortex model and quasi-steady method. It was found that in the presence of bias flow, strong vortex shedding also occurred at an orifice when the incident sound intensity was very high, resulting in a substantial acoustic absorption. The analysis showed that, when the ratio of the fluctuating velocity amplitude to bias flow velocity was within the range from 0.3 to 4.0, the orifice flow was in a transition state between the two limit cases dominated by bias flow and high sound intensity respectively.