An experimental study on transitional boundary layer exciting elastic structures in marine applications

In this paper the results of an experimental campaign aimed at characterizing the wall pressure fluctuations beneath transitional boundary layer acting along the bulbous bow of a fast ship are presented. The measurements have been performed on scaled model of bulbous bow at CNR-INSEAN towing tank n°1, which is 470 m long, 13.5 m wide and 6.5 m deep. The purpose of the present work is to provide experimental information on the fundamental process involved on boundary layer transition from the analysis of wall pressure spectra. The study focuses on three aspects: 1) examining the intermittency factors, which may be defined as the fractional of time that the flow is turbulent, 2) examining the scaling laws for the auto spectral density of wall pressure fluctuations in the transition process, 3) examining the evolution of the spectral distribution of the wall pressure fluctuations