Hydrodynamic characteristics of high speed planing hulls, including trim effects

Authors: AHMADREZA KOHANSAL, HASSAN GHASSEMI, MAHMOUD GHIASI

Abstract: The main objective of this work was to introduce and validate an appropriate algorithm for studying the hydrodynamic characteristics (i.e. pressure distribution, lift, drag, and wave pattern) of 3D planing hulls and wedge-shapes, including trim effects, moving at a constant speed on the surface of calm water. The work builds on the earlier work of the authors, paying more attention to wave pattern analysis. An integral equation was derived from Green's theorem and the unknown pressure distributions on each element were determined by solving an integral equation relating the potentials on the planing hull and the free surface. The hydrodynamic characteristics of the planing hull were calculated numerically in different wetted length-to-beam ratios, deadrise angles, trim angles, and Froude numbers. The effect of spray during planing was considered in the computations of numerical results. Computational results are presented and compared with existing theories and experiments. It is shown that the agreement between the results of experimental measurements and those of the present numerical method is satisfactory.

Keywords: Planing hulls, wedge-shape, boundary element method, free surface, trim effect, wave pattern

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