Flow induced structural noise on a sonar dome of a ship

The turbulent boundary layer pressure field on the exterior of the sonar dome is the major contributor of the sonar self-noise above a certain speed of the vessel. In particular, interior noise levels are influenced by hydrodynamic coincidence, which occurs when the convection speed in the turbulent boundary layer matches the flexural wave speed in the ship hull panels. Calculation of the structural vibrations and of the noise radiated inside the dome preliminarily requires a valid statistical description of wall pressure fluctuations (WPF) beneath the turbulent boundary layer. For this reason, an experimental campaign performed on a scaled geometry of the bulbous bow of a fast ship on a towing tank allowed the identification of a suitable model for cross spectral density of the wall pressure fluctuations. The wall vibration statistics and the acoustic radiation are computed using a coupled acoustic-structural code with the modeled load for different velocities. Preliminary, mean boundary layer parameters have been obtained with a finite volume code that solves the Reynolds Averaged Navier Stokes Equations.