Study on the transfer process of suspended matter in Lake Taihu

• 1、Department of Environmental Science and Engineering, Hohai University

Abstract： Based on the experiment and numerical model, the transfer process of suspended matter under the interaction of wave and current was studies.The followings are the results. Firstly, when the mean wind speed was less than 8 meter per second, the resuspend flux of suspended matter got bigger with the increase of wind speed. The relationship between resuspend flux and wind speed are Positive correlation relation.The formula method of Gansith is suitable for computing the resuspend flux of Lake Taihu. Secondly, When the suspended matter concentration was low, no clear relationship was found between settling velocity and suspended matter concentration. But settling velocity obviously rose with the increase of suspended matter concentration while the latter was high. Based on the data of four hydrostatic experiments, it was found that settling velocity of suspended matter and suspended matter concentration fitted in Logistic Curve.Thirdly, the hydrodynamic process of Lake Taihu was described properly based on coupling the wave and current. Finally, in the SS model, the combined effects of wave and current were included. The amounts of suspended and precipitated sediments near lake bed surface layer were treated separately. The stochastic characteristics of turbulent flow pulsation near lake bed were also considered, and the start-up conditions of sediment suspension were introduced to the model. The model elucidated the mutual exchange processes between sediment particles in SS and active sediments within and on bed surface layer. Simulated results showed that lake current had relatively significant effects on the SSC at littoral areas of Lake Taihu, while SSC at the central area of the lake was mainly influenced by wave.

Keywords： wave current Lake Taihu suspended matter numerical model