A Fully Nonlinear Potential Flow Based 2D Numerical Wave Tank Using Multiple Flux Boundary Element Method

Abstract

Abstract Numerical wave tanks are the cutting-edge tool for modeling a fully nonlinear free surface wave. Potential flow modeling based Numerical Wave Tank (NWT) is a powerful approach when a robust solver is needed for nonlinear wave structure interaction problems of practical significance. In this paper, a Mixed Euler Lagrange (MEL) solution based on Higher Order Boundary Element Method (HOBEM) is used for modeling the NWT. Free surface velocities are calculated by solving the boundary value problem using HOBEM in the Eulerian frame of reference while the time integration happens in the Lagrangian frame. However, the traditional HOBEM suffers from the so called ‘corner problem’, where the normal vector at the physical corner of a wave tank model becomes ill defined, leading to errors. This paper presents the multiple flux technique which is used to solve the corner problem in a HOBEM based numerical wave tank. The comparison of the multiple flux technique is made with a traditional HOBEM based boundary value problem while discussing its implementation in detail. A two-dimensional NWT based on multiple flux boundary element method and Mixed Euler Lagrange (MEL) technique with fully nonlinear free surface boundary is used for generating nonlinear waves.