Measurements and modelling of turbulent boundary layer excitation and induced structural response on a ship: PART II full scale structural response

Turbulent flow around the ship is one of the main sources of vibrations for hull, appendages and propeller. In particular, vibrations induced on the wetted hull panels by the turbulent boundary layer can propagate through the ship structures generating undesirable noise in a quite large frequency range. To investigate and quantify TBL effects on noise level on board, acceleration measurements have been performed on a hull ribbed panel of Ro-Ro Pax ship and used to validate the results obtained by two different numerical procedures developed to characterise the hull panel response. The wall pressure fluctuation load has been modelled using semi-empirical models specialized for the present case on the basis of full scale pressure measurements performed on the same ship. The first numerical analysis, based on Finite Element and on in house codes, is aimed at validating models for wall pressure spectra description. In a second phase, the application of the Statistical Energy Analysis allows to determine the response of a larger portion of the ship hull in correspondence of the bow region and to estimate the noise radiated on board.