Calculation of Viscous Pressure Resistance of Ships Based on a Higher Order Boundary Layer Theory

概要

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An attempt was made to calculate viscous resistance of ships by applying a higher order boundary layer theory instead of the conventional one. In the higher order theory, the pressure variation across the boundary layer due to the effect of surface curvatures is taken into account. The calculation method adopted here belongs to the so-called integral method. Coles' wall-wake law is used as the velocity family and an entrainment equation as the auxiliary equation. The velocity at the edge of the boundary layer is calculated considering the displacement effect of the boundary layer. For several different types of ships, numerical calculations of viscous resistance, which is the sum of viscous pressure resistance and frictional resistance, were made and compared with the towing test results. As a consequence, good agreement was obtained for fine ships but a large discrepancy was found for full ships. Comparison of the calculated results between high and low Reynolds numbers corresponding to ship and model respectively are also shown.