摘要
局部地形对于河口动量和能量平衡有重要作用,影响了潮波性质和物质输运特性。选取珠江河口崖门这一典型的地貌单元,通过水尺和座底式支架的观测,对其特殊地形边界影响下的动力结构进行了探讨。结果表明:(1)过水面积的缩窄导致崖门口处形成局部高水位区,来流方向水位壅高,去流方向水位梯度增大;(2)忽略斜压作用的情况下,由水位梯度所产生的正压项是主要的动力项。沿河道方向的二维垂向平均动量平衡中,急流时刻主要是正压项和对流加速度项平衡,憩流时刻主要是正压项和局地加速度项平衡;(3)地形变化所产生的形态阻力比床面粗糙所产生的肤面阻力要大数倍到一个数量级。
The local topography plays a significant role in estuarine momentum balance,tidal energy balance,tidal properties and sediment transport.Taking the typical geomorphic unit in the Pearl River estuary named Yamen as an example,water level guaging and bottom-mounted tripod measurements were conducted to explore the dynamic structure induced by the topographic boundary.The results show that：（1）the narrowing of the cross-sections Yamen in area leads to a backwater in the opposite-flow direction,increaseing the water level gradient in the downflow direction.（2）The baratropic force induced by the water level gradient is a primary term in the momentum equation.The depth-averaged along-channel momentum balance is achieved between baratropic force and advection during the peak tide,and between baratropic force and local acceleration during the slack tide.（3）The form drag induced by topographic features is several times to one order in magnitude larger than the skin drag caused by bed roughness.
出处
《海洋学报》
CAS
CSCD
北大核心
2013年第5期29-36,共8页
基金
国家自然科学基金(41006050
41176067)
中山大学青年教师培育项目(11lgpy59)
国家重大科学研究计划(2013CB956502)
珠江水利委员会珠江水利科学研究院开放研究基金(2013KJ07)
中山大学青年教师起步计划
关键词
地形边界
动力结构
动量平衡
珠江河口
topographic boundary
dynamic structure
momentum balance
Pearl River Estuary
