Prediction of hydrodynamic forces on planing prismatic bodies by flat plate pressure distribution formula

Abstract

The weight of a planing hull is supported by buoyancy and hydrodynamic forces while planing. In particular, the hydrodynamic forces play a bigger role as the forward speed of a planing hull gets higher. So the accurate estimation of hydrodynamic forces is required for prediction of running attitude or resistance of a planing hull. In this study, new calculation method is proposed for the calculation of hydrodynamic forces on planing hulls. The bottom of a 3D prismatic body is divided into several longitudinal strips, and analytic 2D flat plate pressure formulas are distributed on each longitudinal strip. And additional considerations are given to the transverse pressure distribution. Estimated bottom pressures are similar to the previous model test results in other papers. Hydrodynamic forces and moments can be obtained by the summation of entire bottom pressure. Calculation results are compared with previous model test results and estimations by Savitsky’s method. It may be easy to apply the proposed method to planing hulls with arbitrary cross-section shapes or deadrise angles.rodynamic forces is required for prediction of running attitude or resistance of a planing hull. In this study, new calculation method is proposed for the calculation of hydrodynamic forces on planing hulls. The bottom of a 3D prismatic body is divided into several longitudinal strips, and analytic 2D flat plate pressure formulas are distributed on each longitudinal strip. And additional considerations are given to the transverse pressure distribution. Estimated bottom pressures are similar to the previous model test results in other papers. Hydrodynamic forces and moments can be obtained by the summation of entire bottom pressure. Calculation results are compared with previous model test results and estimations by Savitsky’s method. It may be easy to apply the proposed method to planing hulls with arbitrary cross-section shapes or deadrise angles.