Numerical Simulations Of Marine Sediment Movement Affected By Water Waves

With the development of industry and agriculture, the pollution of marine environment is increasing seriously. The movement of sediment, which shows an important role on seawater quality, attracts more and more attentions. The forecast and control of seawater quality becomes very hard for the complex movement of sediment. As the development of computers, the numerical simulation of sediment movement based on the hydrodynamics is becoming possible.The wave is introduced by an oscillating plane wave-maker and an artificial damping layer is presented to absorb the reflection wave. The air-water interface interface is tracked by VOF method. The control-volume-based technique is used to convert the governing equations to algebraic equations that can be solved numerically. By comparing the theorical results, the correctness and the stability of our numerical wave tank is proved.Suppose the sediment is a Newtonian fluid, the surface movement of turbid water with different water containing is studied. The results show that the water containing has little influence on the property of surface wave. Furthermore, the effects of surface wave amplitude are considered. It is found that the wavelength keeps unchangeable when the amplitude is small and in linearity. As the amplitude is increased to certain value, the nonlinearity comes into effects to enlarge the wavelength slightly. This agrees well with the experimental result of former approach. The influence of water depth on wave propagation is also simulated. It is found that water depth has large influence on the wavelength. The deeper the water depth, the longer the wavelength.In the end, the interaction of the air-water-sediment system is investigated. The results show that VOF method can trace the movement of two interfaces simultaneously. The movement of air-water has influence on that of water-sediment, and on the contrary, the effect of water-sediment is not obvious on air-water movement.