A Prediction Method for Ship Viscous Resistance by Boundary Layer Theory

Abstract

A simple integral-type boundary-layer calculation method is applied to the prediction of ship viscous resistance. A calculation method for the vortex resistance due to the stern bilge vortex is evaluated from the energy-loss concept using the crossflow quantities in the stern boundary layer. The ship viscous resistance thus consists both of the streamwise momentum loss and of the crossflow energy loss. A regression analysis of the resistance shows a fairly good agreement between the theory and experiments.The local development of the viscous resistance components near stern is also discussed in terms of the boundary layer quantities. The potential-flow quantities like pressure gradient and streamline convergences are related to the boundary layer development and then the viscous resistance. The present method can be applied to ship-stern form improvement for reducing viscous resistance.