Etude expérimentale des effets de hauteur d'eau finie, de confinement latéral et de courant sur les sillages et la résistance à l'avancement des navires.

摘要

This thesis presents an experimental study of the effects of the waterway confinement and the current on ships wakes and drag. Two generic hulls representative of maritime and river ships have been studied in several bathymetric configurations in the towing tank of the Institut Pprime. Optical measurement methods based on a stereovision principle have been set up to measure the free surface deformations. The spatial extent and the resolution permits to lead a fine analysis of the wakes in the spectral space in order to decompose them into a hydrodynamic component and an undulatory component, respectively in the near-field and the far-field of the ship hull. The results obtained in a deep waterway configuration highlight the non-linearity of the ship wakes, which results in a modification of the shape of the envelop of the wave field in the real space. The results obtained in a shallow waterway configuration show a modification of the shape of the ship wakes and a different distribution of the energy between the wave systems. The influence of the shape and the speed of the ships on the amplitude of the hydrodynamic response and the return current is also identified. The comparison of the measurements in the presence of a counter-current with the results in calm water show an increase of the amplitude of the waves and an enlargement of the wash zone on the walls of the canal. Drag forces measurements with a multicomponent dynamometer give access to resistance curves for each configuration. The increase of the ship resistance in shallow water is put in parallel with the increase of the amplitude and the wavelength of the transverse waves.