Research On Suspended-load Transport Under Oscillatory Flow

Wave is the most important dynamic factor of coastal evolution,seabed erosion, offshore structures destruction. The suspended sediment motion under wave action is the research emphasis of the coastal sediment movement. The characteristic of the suspended sediment motion, different from unidirectional flow, has its particularity. This paper deducts a new theory model of the velocity field and the vertical distribution of suspended sediments, by adopting new assumptions and reasonable modification.1,In this dissertation, we introduce a new on turbulent viscosity and obtain a relatively reasonable flow field distribution, using the depth weighted average method in turbulent boundary layer. The analytical solution of is similar to the laminar boundary layer, except that we replace the depth of the laminar boundary layer with the depth of the turbulent boundary layer.2,Considering turbulent diffusion coefficient and sediment movement effected by the harmonic motion of the wave water particle in main flow region, we obtain the proportional coefficient, and get the full-depth turbulent diffusion coefficient formula by using of linearity interpolation. We emphatically analyzes the proportional coefficient in the upper flow area changing with diameter, wave period. Besides, we introduce the relative particle Reynolds number to determine the applicable condition, and analyze its relationship with diameter, wave period.3,Considering the sediment deposition effected by sediment concentration, we modify reasonably the vertical suspended sediment distribution formula, and build the full-depth suspended-load model. We introduce the parameter, the impact factor of concentration, representing the effect of sediment concentration. This paper emphatically analyzes its relationship with sediment concentration on any depth and the reference concentration.