东山湾波浪对悬沙浓度场影响的数值模拟研究

研究了波致底切应力和二维辐射应力对悬沙的作用.首先对东山湾的水动力进行了数值模拟并与实测资料进行了对比检验,然后对东山湾悬浮泥沙进行了考虑波浪和不考虑波浪两种情况下的数值模拟并与实测资料进行了相关对比分析.在模式建立过程中,依据东山湾独特的窄口型半封闭河口海湾的特点,基于ECOMSED模式（2002）建立了东山湾三维水动力模型,并通过第三代海浪模式MASNUM加入了波浪对底切应力及辐射应力的影响,通过ECOMSED中的底边界层模型考虑了波浪增强底摩擦的作用,综合分析了东山湾的水动力及泥沙状况.结果表明在东山湾数值模拟中,该模式能较好地模拟这类海域的水动力及泥沙输运状况.在东山湾模拟计算中,潮流的作用强于波浪的作用,但考虑波浪因素后,泥沙模拟结果更好.在波浪的作用中,底切应力相比于二维辐射应力占有绝对的优势,两者相差2个量级以上,因此可以不考虑二维辐射应力的影响.

Simulation study of wave effects on the suspended sediment concentration in Dongshan Bay

We studied the effects of wave induced bottom shear stress and two-dimensional radiation stress on the suspended sediment concentration（SSC）.At first,we made the comparison of the hydrodynamic simulation and observation of Dongshan Bay.Then we simulated SSC in cases of considering and no considering waves,respectively.We also compared and studied the results with the observed and the simulated.In our three-dimensional hydrodynamic model of ECOMSED（2002） of the Dongshan Bay,we considered not only the characters of the Bay,such as its narrow mouth,semi-closed shape and river inflow,but also the wave factors of wave induced bottom shear stress and two-dimensional radiation stress,which were calculated by MASNUM Wave Model of the 3rd generation wave model.We considered the enhanced bottom friction using the bottom boundary model of ECOMSED and analyzed the hydrodynamic and SSC characteristics of the Dongshan Bay.The results indicated that this model could well simulate the hydrodynamic and SSC conditions in such kind of bays.From our simulations,the effect of currents is greater than waves,but the results are greatly improved when considering waves.When comparing the effects of wave induced bottom shear stress and two-dimensional radiation stress,we can find that the wave induced bottom shear stress predominates the radiation stress.The former one is more than 2 orders magnitude higher than the later and so we can ignore the later in the simulations.