Numerical Experimental Study Of The Spring Tide Hydrodynamic Response Of Sand Evacuation In Taizhou Shoal

The tidal flat along Taizhou bay is rich in sand which is good in quality, and it deposits very quickly. Sand evacuation in tidal flat is not only good for shipping, but can also help address sand constraints. But sand evacuation blindly can cause many problems, like changes of river bed and regime, enhancement of the turbulence of flow and tidal power. So the research on hydrodynamic response of study area after sand evacuating turns out to be very important.In this paper, established a planar2D flow hydrodynamic mathematical model base on Mike21, to simulate the flow field of Taizhou tidal flat after sand evacuating, and analyze the impacts of sand evacuation on the flow field in three cases. We saw the flow field changing in the groove and its surrounding waters due to dredging channel in different slopes. After calculating and analyzing, the main research results and conclusions are:(1). Both in the flood tide and ebb tide period, velocity of the water surrounding the groove. increases, but velocity of some water inside the groove decreases, and a steeper slope chosen in the numerical experiment produces m-ore distant effects of flow field.(2). The changes of mean flow velocity both in the flood tide and ebb tide period depend on location. Mean flow velocity on both ends of the midline of the groove decrease most, while some increase a little in the middle filed of the groove during the ebb tide period. The steeper slope chosen in t-he numerical experiment makes less discount of flow velocity.(3). Varieties of groove slope have influences on the maximum velocity of flood and ebb tide period, while have nothing to do with flow velocity at the foot of the groove slope. The maximum velocity of water surrounding the upstream groove slope is larger than the maximum velocity of water surrounding the downstream groove slope during the flood tide period, but the situation is just the opposite during the ebb tide period.(4).Velocity of water on and surrounding the groove slope changes after sand evacuating, while the sea level has an effect on the changes, the lower the sea level, the greater the effect.