【摘要】 泥沙运动作为水流和底床相互作用的纽带,是河流、河口及海岸工程研究的重要内容。在潮波作用明显的河口、海岸地区,周期性的动力作用下的泥沙运动具有往复和可逆的特征,因此研究这类水域的泥沙的净输运更具有实际的意义。基于泥沙输运和流速呈指数关系假设,建立潮流环境下的泥沙全沙净输运的解析解公式,并对该公式的计算结果和数值计算以及数学模型的结果进行了检验和验证,结果表明本研究提出的公式能较好地反应潮流环境下的泥沙净输运。由此,基于本公式采用潮流分潮调和常数可计算得到全沙净输运,并可以分析各分潮流及其相互作用与泥沙净输运的关系。研究结果显示,在受径流影响较大的半日潮河口,S2、MS4、M2三潮相互作用对全沙净输运的贡献显著高于通常的潮流不对称作用,即M2、M4的相互作用。此外,河口区域径流导致的余流对泥沙净输运的贡献不可忽略,特别是在洪季,大径流量条件下往往导致余流较大,其对泥沙净输运的贡献所占比例较大。更多还原

【Abstract】 Sediment transport,as a link of interaction between current and bed,is an important issue of river,estuary and coastal engineering research. In tide-dominated estuaries and coastal areas, sediment transport driven by periodic dynamic forces is reciprocating and reversible. Therefore,study on net sediment transport in these areas is rather practical. Based on the hypothesis of sediment transport proportional to the exponent of current velocity,the analytical expression of net total load sediment transport with tide current constituents is derived. The present analytical expression has been verified against the result of numerical calculation and the result of mathematic model. The result shows that the proposed analytical expression can represent the net sediment transport well in tidal environment. Thus,the net sediment transport can be calculated based on the present expression by using tidal current constituents,and the relationship between interaction of tidal constituent and sediment transport can be achieved. The result reveals that the contribution of the triple interaction of S2,MS4 and M2 to the net sediment transport is significantly higher than that of classic tidal asymmetry( i.e.,interaction of M2 and M4). In addition,the contribution of residual current in estuaries caused by large runoff from upstream to the net sediment transport cannot be neglected. Especially in the flood season,the contribution of residual flow increases obviously.更多还原