Numerical Simulation Of Wave Overtopping Based On Dual SPHysics Model

Wave overtopping on seawall may lead to flooding over the area behind the seawall,being unusable of normal operations and even potential damage of the structure itself.Accurate estimation and simulation of wave overtopping have great significance in the design and usage of seawall.DualSPHysics is a weakly compressible,open-source hydrodynamic SPH model,which can easily capture large free surface deformation in strong nonlinear flows.DualSPHysics model uses parallelized technique and has high computation efficiency.Wave overtopping is studied by using the DualSPHysics model.The main research contents and conclusions obtained are as follows:(1)Active wave absorption system(AWAS)has been implemented in DualSPHysics model both for regular and random waves.Numerical results are validated by theoretical solutions,showing that the reflected secondary waves are well absorbed.(2)Numerical simulations of regular and random wave overtopping are conducted for sloping seawalls by using the DualSPHysics model combined with AWAS.The numerical results are compared with the experimental data of Saville(1955)and other numerical data of OpenFOAM et al.Good agreements are obtained,which show that DualSPHysics model can be used to simulate regular a random wave overtopping with good accuracy.Comparisions between numerical results of DualSPHysics and Sainflou formula as well as experiment data of wave pressure performed in large-scale wave flume semi-circular breakwater show that DualSPHysics model provides good prediction of wave impact on coastal structures.(3)DualSPHysics model is employed to reproduce random wave overtopping on breakwaters with different slopes.Comparision has been conducted among predicted results of overtopping discharge of irregular wave by the main popular formulas.It shows that the prediction formula in Coastal Engineering Manual gives the best results.Numerical simulation of wave overtopping of a sloping seawall with armour block is carried out and comparisons between smooth sloping seawall and sloping seawall with armour block have been conducted.Results show that armour block can increase wave energy dissipation on wave overtopping process.However,there exists structure and fluid particles separation phenomenon in the modeled results,which needs futher improvements.(4)Numerical simulations of regular wave overtopping on six different types of seawalls have been conducted by using the DualSPHysics model.Comparisions between vertical wall and curved wall as well as recurved wall on wave overtopping discharge and wave force show that recurved wall reduces wave overtopping discharge effectively but the wave force exerting on recurved wall is large;in contrast,wave overtopping discharge of curved wall and vertical wall are much larger and the wave force exerting on curved wall is much smaller.Finally,the influences of relative freeboard,wave period and water depth at the toe of seawall have been discussed on wave overtopping discharge of different seawalls,respectively.