长江口局部河段三维潮流数值模拟研究

摘要

To further understand the hydrodynamic characteristics of Yangtze estuary, a 3D mathematical model is established for several locations such as south branch, Nangang and Beigang waterway in south branch, based on the unstructured grid in FVM. The verification shows that the model can simulate the flow structure of Yangtze estuary correctly. Therefore, the charac-teristics of surface and bottom flow in the entrance of Beigang waterway and the vertical flow structure in Xinqiao passage channel are analyzed. It suggests that for the entrance of Beigang waterway, the tidal ebb difference of surface and bottom is larger, while the tidal surge difference is smaller. For the Xinqiao passage channel, during a tidal surge, the difference of vertical velocity gra-dient at the upper-middle layer and middle-lower layer is significant, while it is smaller during a tidal ebb.%为了准确深入地认识长江口区水动力特征，基于非结构网格有限体积法，建立了长江口南支、南北港局部河段三维潮流数学模型。模型验证结果良好，说明其能够正确反映水流的三维运动形式。在此基础上，分析了北港入口处表底层水流特征以及新桥通道垂向水流结构。结果表明，北港入口处，落急值在表层与底层差别较大，涨急值差别相对较小。新桥通道处，涨急时，中上层与中下层垂向流速梯度差异明显，落急差异相对较小。