A modal approach for wall impedance estimate in a test section of a cavitation tunnel

The measurement of the underwater radiated noise at a model scale is generally the preferred way to predict this important feature at sea, using scaling laws. The accuracy of such method depends on many parameters. The measurement accuracy in a test section of a cavitation depends on the model used for the transfer function or for the propagation model. Thus, the knowledge of the wall acoustic impedance appears as an important parameter in such studies. The proposed study presents a modal method dedicated to the estimate of the wall impedance of a cavitation tunnel test section. It is based on a reverse method to estimate the impedance from measurements assuming that the sensor locations are known.