Numerical Prediction of Wall Pressure Fluctuations in a Turbulent Boundary Layer on a Cylinder in Axial Flow

Abstract

Flow noise originating in the turbulent boundary layer (TBL) often severely limits the performance of towed sonar cylinder and therefore it is necessary to predict this noise for the design of efficient towed cylinder. This paper presents large eddy simulation methodology to establish the TBL properties and wall pressure fluctuations on a 3 m long cylinder with length to diameter ratio of 315 in the operating speed of 11.4 m/s in air. The computed flow induced sound is compared with experimental measurement available in the literature successfully. The effectiveness of scaling the flow noise spectra with diameter and tow speed is discussed and non-dimensional wall pressure spectra presented with respect to non-dimensional frequency. The overall sound pressure levels are also compared with experimental data that show good accuracy achieved by the proposed numerical methodology.