Measurements and modelling of turbulent boundary layer excitation and induced structural response on a ship: PART I full scale wall pressure fluctuations

To comply with the more and more restrictive international standards and regulations for noise and vibration levels on board passenger ships, a renewed interest on secondary N&V sources, with respect to propeller and machinery sources, has been observed. In particular, the increase of ship performances in terms of velocity has been directed on study the hydrodynamic noise sources and among the others turbulent boundary layer (TBL). The great difficulties encountered in simulating the wall pressure fluctuations (WPF) due to TBL at high Reynolds numbers and for complex configurations typical of a real ship have pushed the research community to develop models for WPF based on theoretical considerations and model scale tests. In particular, scaling laws for pressure spectra have been established at least for simple geometries and flow conditions and models of cross spectral density for their spatial characterization have been obtained. Unfortunately, model scale tests do not allow reaching Reynolds number values comparable with full scale conditions. Therefore, to validate current models an experimental campaign devoted to WPF measurements have been performed on the hull of a Ro-Ro Pax vessel. Numerical simulations of the flow around the ship hull were performed to evaluate mean flow parameters.