A Time-Domain Boundary Element Method for Wave Diffraction in a Two-Layer Fluid

الملخص EN

A time-domain numerical model is established based on the higher-order boundary element method (HOBEM) to simulate wave diffraction problem in a two-layer fluid of finite depth.

There are two possible incident wave modes (surface-wave mode and internal-wave mode) exist in the incident wave for a prescribed frequency in a two-layer fluid.

For surface-wave mode, the hydrodynamic characters of fluid particles are similar to single-layer fluid.

For the internal-wave mode, through the definition of a new function respected to velocity potentials of upper and lower fluid on the interface by using matching condition, a single set of linear equations is set up to compute the time histories of wave forces and wave profiles by using a fourth-order Runge-Kutta method.

An artificial damping layer is adopted both on the free surface and interface to avoid the wave reflection.

Examinations of the accuracy of this time-domain algorithm are carried out for a truncated cylinder and a rectangular barge, and the results demonstrate the effectiveness of this method.