The smoothed particle hydrodynamics (SPH) method has been proved as a powerful algorithm for fluid mechanics, especially in the simulation of free surface flows with high speeds or drastic impacts. The solid boundary treatment method is important for the accuracy and stability of the numerical results, as the support domain of fluid particles is truncated near the vicinity of the boundary. This paper presents two commonly used methods for simulating a solid boundary in SPH simulations. Emphasis is placed on the description of the methods, definition of the boundary particles’ parameters, and discussion of their advantages and shortcomings. The classical dam break simulation is conducted using self-developed code and open source models such as DualSPHysics and PySPH in order to investigate the effects of the boundary methods. The results show that methods based on dynamic boundary particles can simulate the free water surface well with a good agreement with experimental results. The conclusions can also be used in research for boundary implementation methods for practical ocean and coastal engineering problems with free surface flows.

This paper presents the results of an experimental investigation on the impact of dam-break-induced surges on a vertical wall. The instantaneous surge height and dynamic pressure on a vertical wall were measured for surges with different reservoir depths of H = 200 mm, 250 mm, and 300 mm. The time-histories of horizontal pressure on the wall were measured using the miniaturized pressure transducers, and the surge heights were recorded with an ultrasonic sensor. The relationships between dynamic pressure and surge height on the vertical wall and during the impact were obtained from recorded raw data. The experimental results highlighted detailed processes on the variation of impact pressure during the surge propagation, impact on the wall, runup, falling, and breakup of the turbulent flow. The time-histories of surge height and dynamic pressure were analyzed, and the results were compared with the hydrostatic pressure on the wall to study wave breaking mechanism of tsunami waves on the wall. Dynamic pressures at the impact instant were found to be approximately three times the corresponding static pressure in the bed, in good agreement with previous research Moreover, the maximum surge runup heights on the wall were between 2.1 and 2.3 times the corresponding initial reservoir depths. The vertical distributions of impact pressure were divided into two hydrodynamic regimes. Based on the impact duration, the first regime occurred less than 0.1 s after the impact with highly non-linear pressure distributions, and the second regime showed a semi-hydrostatic pressure distribution from 0.5 s to 0.7 s. The results presented in this study are suitable for the design of coastal infrastructures and can be used to validate numerical models.

Over the past decades, hydraulic surge generated by dam-break waves has been used to simulate the effects of tsunamis on coastal infrastructure. This study investigates the slope effects on hydrodynamic loading of dam-break waves on structure when propagating over four different inclined beds (0-, 5-, 10-, 15-degree) by experiment and numerical simulation using OpenFOAM and DualSPHysics. Except for small discrepancies in the pressure time-history, numerical results obtained with both OpenFOAM and DualSPHysics agreed closely with the experimental dynamic pressures. The results revealed that the hydrodynamic pressure decreased after an initial impact peak from the lowest transducers in the 5-, 10-, and 15-degree cases when compared with the horizontal case. However, the dynamic pressure of transducers at same corresponding level increased with an increase in the slope. The integrated experimental hydrodynamic forces were similar to the numerical results for the 0- and 5-degree cases, while they were higher for the 10- and 15-degree cases due to insufficient pressure data. By investigating the relation between the force decrease and slopes, a non-dimensional reduction factor was proposed from the linear fitness for slope effects estimation. This experimental and numerical study can provide novel insight on the hydrodynamic force calculation of tsunami-like surges on coastal infrastructures when considering beach slope.