Numerical Simulation Of Revetment Overtopping With Plant Influence

In river and coastal areas,revetment works play an important role in defending flood and wave.The traditional concrete revetments may destruct the ecological environment and the water landscape while they protect the land area.Therefore,the ecological revetment measures,using plants to reduce waves,improve the stability of bank slope,create beautiful natural landscape and enhance the self-purification ability of water bodies,have been introduced into bank revetment projects in recent years.In order to understang the interaction between waves and ecological revetment,based on OpenFOAM,an open source computational fluid dynamics software,a threedimensional numerical wave tank was established which took into account particle movement and flexible plant deformation.Numerical simulation investigation on wave run up and overtopping on honeycomb type ecological revetment with vegetation was carried out.The main contents and conclusions of this thesis are as follows.(1)Based on the three-dimensional numerical wave flume considering particle motion,the ecological revetment model was established by using DPM to simulate gravel movement.According to the physical model experiment of real plants,corresponding cases are set up to simulate the process of wave runup and overtopping considering the influence of plants.The numerical simulation results are in good agreement with the experimental results,indicating that the established model can simulate the interaction of waves,plants,gravel and honeycomb structure.(2)Based on the ecological revetment model,multiple cases were set up and the influence of wave period,wave height and vegetation density on overtopping over the ecological revetment was discussed according to the numerical model results.At the same time,based on simulation results,the empirical formula of overtopping under the influence of plants is proposed.The deformation of bank slope under different wave conditions and vegetation density was analyzed.(3)The dynamic boundary model of flexible plants was developed to simulate the wave attenuation due to plants with different stiffness.The simulation results are in good agreement with the experimental results,indicating that the dynamic boundary model can accurately simulate the movement and deformation of plants.The simulation results also show that there is a sensitive area for the influence of plant stiffness on wave attenuation coefficient.At the same time,the effect of plant stiffness on wave overtopping of the ecological revetment was analyzed.