A Semiempirical Procedure for Computing the Water-pressure Distribution on Flat and V-bottom Prismatic Surfaces During Impact Or Planing

Résumé du livre

A semiempirical procedure is presented for computing the water-pressure distribution on flat and V-bottom prismatic surfaces during planing or landings. For the rectangular flat plate, a consideration of several previous theoretical derivations and some observations of the experimental data lead to the development of simple equations which are in good agreement with experimental data for trims below 30 deg. and for wetted-length-beam ratios at least up to 3.3. This development is based primarily on the assumption that the longitudinal distribution of pressure on a rectangular flat plate is substantially a function only of the normal-load coefficient so that this distribution may be computed from the existing theory for two-dimensional flow. The transverse distribution of pressure is obtained as a compromise between the available theoretical treatments for very small and very large wetted length-beam ratios. For a V-bottom prismatic surface with appreciable chine immersion, the pressures on chine-immersed sections of a model having an angle of dead rise of 30 deg. are found to be very similar to those on the corresponding flat plate so that a simple modification of the flat-plate equations can be used to predict approximately the pressures on V-bottom surfaces.