A Study On Suspended Sediment Movement Under Waves

The research on suspension and motion laws of sediment under waves are important both in the coastal dynamics and coastal engineering. The prior research usually focuses on its average vertical distribution over one wave period under stable waves, which does not take the convective term into consideration and is not helpful to understand the suspension mechanism of sediment. In order to obtain the inherent mechanism, the suspending process and vertical distribution of sediment are studied by means of both mathematical model and physical model. The main results are as follows.1. Sediment suspension experiment under waves was conducted, in which the periodically averaged vertical distribution of sediment concentration was sampled.2. A mathematical model was adopted to simulate the vertical distribution of sediment under waves. In the computation, firstly, numerical wave flume is used to obtained the wave parameters, including velocity field, turbulence parameters and VOF values. It is found in the numerical tests, that the simulated wave shape begins to attenuate significantly after about 40 waves. Thus the last three waves are picked up as the input parameters for the computation of suspended sediment movement. The temporal results of vertical profiles of sediment concentration are obtained, which are compared with the measurements. The results are roughly agree.