مدل سازي عددي امواج سطحي ناشي از اجسام شناور متحرك در آب كم عمق

Numerical calculation of free-surface flow around moving body at finite depth of water

Potential flow around the marine structures based on Greensʹ Theorem has been developed in ocean engineering problems. The main goal of surface wave parameters definition around body is calculation of wave making resistance and hydrodynamic coefficients. As body moves in deep water, fluid particles can move around hull freely but when it enters shallow water the particles movement is restricted and therefore wave pattern around body changes significantly. Changes mentioned can be considered as an interesting purpose in present study. Laplace equation in irrotational, inviscid, incompressible control volume of fluid is released as governing equation. The three-dimensional Boundary Element method is accomplished to calculate potential function at any point of computational field. To satisfy Neumann boundary conditions, the image method is employed. The Green function consists three parts. First part relates to the location of the singularity in the domain and its images with respect to the bottom. In The Second part, the free surface disturbance due to the singularity and its images is affected. Radiation condition is applied in third part. Numerical computations are applied to free surface waves generated by Wigley hull and moving pressure disturbance for the steady problem. The characteristic of wash wave such as the wave pattern on the free surface for different depth froude numbers and speed coefficients for pressure point in shallow water are reasonably predicted.