Duct aeroacoustic control by multiple flexible panels

The flow duct aeroacoustic control method by using a flush-mounted membrane has been proven that provides excellent silencing performance for broadband noise. The principle is to utilize the acoustically excited panel vibration to affect the incident noise propagation, reflect the noise to upstream and cause transmission loss in downstream. In addition, the reflection level is able to be promoted by using more than one membrane. The performance of the aeroacoustic control by using two membranes is studied theoretically and numerically in the present work. A simplified model in frequency domain is built and solved analytically to resolve the acoustic-structural response when the double panels in the duct are exposed to broadband incident acoustic wave. Besides, a time domain analysis is also conducted by solving the Navier-Stokes equations coupled with the membrane dynamic numerically for validating the frequency domain model. The acoustic-structural response under the two membranes setup is studied. The silencing performance is much better than that with only one membrane.