Interactions between wavemaking and the boundary layer and wake of a ship model

A detailed experimental study has been conducted in a towing tank on a 3.048-meter-long mathematical model, known as the Wigley hull, to study the effects of viscosity on the wavemaking resistance of the ship form. The measurements included total resistance, viscous resistance, pressure distribution, and boundary-layer measurements of the model at zero trim and sinkage. The three-dimensional boundary-layer measurements extend from midship to a distance of 0.1 model lengths downstream of the stern and include the pressure distribution on the body, and three components of the mean velocity measured by means of a five-hole pitot tube. These measurements were carried out for four Froude numbers of 0.266, 0.313, 0.350 and 0.400. A numerical method, using the small-crossflow approximation of the boundary-layer equations, has been employed to calculate the boundary-layer characteristics along the streamlines on the hull which were obtained by using Guilloton's methode A comparison between calculation and experimental results has been made. The wave-resistance coefficients of the ship form have been calculated by the Michell integral, using the Michell thin-ship centerplane distribution, a hull surface distribution and a slender-body centerplane distribution. These calculations have been carried out for two different cases, 1) wave resistance calculation without the effect of the boundary layer and wake, and 2) calculations including these effects. These calculations have been carried out only to first order and have been compared with the residuary resistance and the wave-profile resistance