Numerical modeling of the water flow around ship hulls

A numerical method based on potential-flow theory using Rankine sources has been developed for the prediction of the flow past ship hulls. For purpose s of validation, the method has been applied initially to the known analyti cal solution of flow past a sphere submerged in an infinite fluid. It was c onfirmed that a significant improvement could be obtained over the original method of Hess and Smith by projecting the collocation points back onto th e actual surface of the sphere with additional smaller gains using submerge nce of the panels below the body surface. The method was then extended by t he introduction of a free-water surface boundary condition and used to calc ulate the wave resistance of a Wigley hull for higher Froude numbers, up to 1.0. Raven's correction to Dawson's original formulation was included and evaluated. It was found that the correction made only a small difference to the calculated wave resistance. The results of the present work were seen to agree closely with experimental data for residual resistance up to a Fro ude number of approximately 0.65 but then give slightly lower values for hi gher Froude numbers. The difference was attributed primarily to the method of deducing the experimental values of the residual resistance from the tot al resistance where the frictional resistance had been based on the static wetted surface area.