Applications of the modified Trefftz method to the simulation of sloshing behaviours

This paper develops a modified Trefftz method (MTM) associated with the group-preserving scheme (GPS) to deal with the two-dimensional non-linear sloshing problem. For non-linear sloshing phenomena, the conventional numerical method may encounter numerical instabilities and numerical dissipation, as the coefficient matrix obtained from the conventional numerical method is ill-posed, and the free surface exhibits non-linear kinematics. To overcome these problems, we introduce the concept of controlled volume into the numerical procedure to prevent the elevation from vanishing, and we take the characteristic length into account to maintain the stability of the new numerical method. Moreover, the use of the GPS eliminates the need to use second-order derivatives, thus increasing the numerical efficiency, and weighting factors can be used to observe the vanishing of the velocity potential. Comparisons of results of the present study with those in the literature show that the numerical results are better than those obtained using previous methods. The method developed here is a simple and stable way to cope with the non-linear sloshing problem.