Time Domain Simulation of Steady ShipWave Problem by a Higher-Order Boundary Element Method

摘要

A 3-D time-domain numerical wave tank using a higher-order boundary element method is newly developed in the framework of linear potential theory, and ship waves generated by the standard Wigley model advancing at constant forward speed in otherwise calm water and the resultant steady wave resistance are computed as verification of the computer code developed. A rectangular computational domain moving with the same forward speed as the ship is introduced, in which an artificial damping beach is installed at an outer portion of the free surface except the downstream side for satisfying the radiation condition. The velocity potential on the ship hull and the normal velocity on the free surface are obtained directly by solving the boundary integral equation, with the Rankine source used as the kernel function. For numerical stability and accuracy, an iterative time-marching scheme is employed for updating both kinematic and dynamic free surface boundary conditions. Thus the boundary integral equation is solved at each time stepping. After validating the convergence with respect to time step and mesh size, the problem for computing the steady waves generated by the Wigley hull is considered as an initial-value problem, increasing the ship’s speed from a state of rest up to a specified constant value. Computed results of the wave pattern and wave resistance are illustrated and compared with experimental measurements, showing satisfactory agreement.