WAVE EQUATION MODEL FOR SHIP WAVES IN BOUNDED SHALLOW WATER

1.　 INTRODUCTIONIn the recentyears,waves in coastal shallow water,generated by marine traffic and in-tensified by port expansion,interaction with structures and reflection of land boundaries,has become a crucial factor affecting waterenvironmentsand engineering operation.In com-parison with the wind waves and ocean swells,waves inside harbor exhibitanomalous waveheight in certain areas.The dominantship waves are hardly dissipated in the harbor due tothe interaction with shorelines,and may…

WAVE EQUATION MODEL FOR SHIP WAVES IN BOUNDED SHALLOW WATER

Ships were modelled as moving pressure disturbances on the free surface of a shallow water basin in the present paper.The moving-pressure generating waves were subjected to the reflection of land boundaries and the radiation of open boundaries.This paper proposed and examined a wave equation model (WEM) to solve the shallow water equations with moving surface pressures simulating ship waves in a bounded shallow water region.The Galerkin finite element method was used to solve a second order wave equation for the free surface elevations and the hydrodynamic pressure of the ship bottom simultaneously.Horizontal velocities were obtained from the momentum equations.Numerical solutions of Series 60 CB=0.6 ships moving with the depth Froude number of Fh=0.6, 1.0, 1.3 in a rectangular shallow water harbor were investigated.Three dimensional surface elevation profiles and the depth-averaged horizontal velocities were analysed.The numerical results characterised very well the ship waves in shallow water.Strong boundary reflection waves were found in the case of high depth Froude number (Fh=1.3).Waves generated by the interactions of two ships moving in the same directions and in the opposite directions were also numerically investigated in the present study.