The Numerical Simulation Of Nonlinear Wave Force On Three-Dimensional Body

Two kinds of nonlinear time-domain coupled numerical models are adopted to calculate the nonlinear wave force acted on a box-shaped ship in harbor. A higher order nonlinear term is also included in the Boussinesq equations to enable the model more applicable for strong nonlinear problems of shallower water waves. A relevant pressure physical experiment was also conducted to validate the model.The coupled numerical model, combining Boussinesq equations with Euler's equations, divides the whole domain into inner domain and outer domain. The inner domain is the area beneath the ship hull, which is governed by the Euler equations. The outer area is the area between the ship and harbor walls, which is governed by the higher order Boussinesq equations. A good agreement is obtained between the numerical results and the experimental data.Another coupled model, combining Boussinesq equations with Laplace equation model, also divides the whole domain into inner domain and outer domain. The inner domain is the area around the ship, Laplace equation governs the flow in this region and is numerically solved by the finite element method. The other area is the outer domain, where the flow is described by the higher-order Boussinesq equations and which is numerically solved by the finite difference method. A new method is applied to implement the matching conditions on the interfaces between the inner domain and the outer domain. The computed nonlinear pressure agree with the experimental data very well, so this coupled model can simulate the fluid motion around the ship more accurately.The analysis between these two kinds of nonlinear time-domain coupled numerical model are conducted, and the results show that the coupled model combining Boussinesq equations with Laplace equation can simulate the nonlinear wave characteristic around the ship and the pressure acted on the ship more accurately. Generally the computation results of these two kinds of coupled model can meet the requirement by the real project, denoting both of them are applicable for calculating the non-linear wave force on a ship in a harbor. Comparatively speaking, the coupled model combining Boussinesq equations with Euler's equations is simple and efficient, while the other one could present more accurate computation results and has a wider application range.