Narrow Results

In this paper, a two-dimensional Lagrangian model based on the weakly compressible smoothed particle hydrodynamics (WCSPH) was developed to explore the hydrodynamics of standing waves impinge on a caisson breakwater. The developed model is validated against experimental data and applied then to analyze the wave horizontal velocity in front of a vertical caisson. The effect of wall steepness was investigated in terms of the steady streaming pattern due to generation of fully to partially standing waves. The numerical results indicated that the partially standing waves generated in front of the sloped caisson change the pattern of steady streaming. For the vertical caisson, the velocity component of recirculating cells increased in front of the vertical wall; whereas, for the sloped caisson it decreased from the sloped wall with reducing the wall steepness. In addition, near the milder sloped wall the intensity of velocity component is higher, which is an important parameter in scour process in front of caisson breakwater.

Lagrangian particle-based methods have opened new perspectives for the investigation of complex problems with large free-surface deformation. Some well-known particle-based methods adopted to solve non-linear hydrodynamics problems are the smoothed parti- cle hydrodynamics (SPH) and the moving particle semi-implicit (MPS). Both methods model the continuum by a system of Lagrangian particles (points), but adopting distinct approaches for the numerical operators, pressure calculation, and boundary conditions. Despite the ability of the particle-based methods in modeling highly nonlinear hydrodynamics, some shortcomings, such as unstable pressure computation and high computational cost remain. In order to assess the performance of these two methods, the weakly-compressible SPH (WCSPH) parallel solver, DualSPHysics, and an in-house incompressible MPS solver are adopted in this work. Two test cases consisting of three-dimensional (3D) dam-break problems are simulated, and wave heights, pressures and forces are compared with the available experimental data. The influence of the artificial viscosity on the accuracy of WCSPH is investigated. Computational times of both solvers are also compared. Finally, the relative benefits of the methods for solving free-surface problems are discussed, therefore providing directions of their applicability.