Kelvin Wakes and Wave Resistance of Cruiser-and Transom-Stern Ships

The steady wave patterns, Kelvin-wake spectra and wave resistance of several realistic ship hulls are computed by a Rankine panel method. Wall-sided as well as transom-stern ships are studied over a broad range of Froude numbers and the importance of enforcing a Kutta-type condition of smooth flow detachment at the transom stern is demonstrated. The lack of numerical damping in the solution scheme permits the reliable prediction of the Kelvin wake far from the ship and allows its use in the evaluation of the free wave spectrum. The wave resistance is evaluated by pressure integration as well as momentum conservation and the merits of the latter method are discussed.