Assessment of statistical features of the diffused acoustic field in a test section of a cavitation tunnel

Abstract

Noise measurements in a cavitation tunnel is the preferred approach for predicting the underwater noise radiated by a propeller at sea. The accuracy of the prediction is linked to the similitude laws used to transform the model scale measurements to the full-scale ones. Besides, this accuracy is obviously linked to the accuracy of the model scale measurements. The knowledge of the acoustical features of the facility used to perform such measurements is then one of the key points of such measurements. The proposed communication presents the recent results obtained in the test section of the Large Cavitation Tunnel (GTH at Val-de-Reuil) to describe the statistics of the diffuse acoustic field. The results show that the diffuse field complies spatially very well with the Gumbel distribution for narrow band levels (expressed in dB for the power spectral density). The limit of the statistical domain (defined as the “Schroeder frequency”) is also estimated thanks to the experimental measurements performed inside the test section.