Acoustic impedance model of perforated elements with both grazing and bias flow

스치는 유동과 관통 유동의 영향을 고려한 천공 요소의 음향 임피던스 모델

The simplified impedance model which can consider a combined flow condition was suggested. Although the strength and position of the shear layer cannot be obtained by a linear sum of two separate contributions when both flows occur together, it was simply assumed that the impedance under the combined flow follows from summing the separate flow impedance. To validate the simplified impedance model, acoustic properties of a concentric resonator was predicted and measured. The predicted transmission loss using the simplified model shows reasonable agreements with measurements. One can find that the simplified impedance model obtained by the superposition of the separate flow impedances can be adjusted to predict the acoustic properties of a concentric resonator.