倚岸型潮流脊体系中的深槽冲刷——以江苏如东海岸为例

Modeling channel scour associated with shore-attached tidal ridges:A case study from Rudong coast,Jiangsu Province

江苏如东海岸的潮流脊体系位于南黄海辐射状沙脊群南部,由沙脊及脊间深槽组成,为"倚岸型"潮流脊体系。本文采用水平一维模型模拟深槽从初始形态冲刷至均衡态的演变过程,用不同的潮差及初始剖面坡度等参数运行该模型,以了解深槽冲刷深度的主要控制因素及其对深槽均衡态的影响。数值实验结果表明:(1)给定初始剖面的坡度、潮差等参数,经历一定时间的冲刷之后剖面达到均衡态,其后剖面形态保持稳定,不随时间改变;(2)若仅给定初始剖面的坡度,则潮差越大,达到均衡态时深槽的冲刷深度越大,而且潮差的变化对冲刷深度有显著影响;(3)若仅给定潮差,则初始剖面的坡度越大,均衡态时深槽的冲刷深度越小且初始剖面坡度的改变对冲刷深度有显著影响。

The tidal ridges off the Rudong coast,Jiangsu Province,are a part of the radial tidal ridge system of the southern Yellow Sea.These ridges and the inter-ridge channels represent a kind of shore-attached tidal ridge systems.In this contribution,the evolution from an initial profile to morphodynamic equilibrium was simulated with a horizontal 1-D model.Numerical experiments were carried out for different tidal ranges and longitudinal bed slopes,to evaluate their influence on the equilibrium state of the channel morphology.The results show that：（1） The channel will reach equilibrium during a certain period of time,if the initial profile of the channel and tidal range are known;（2） with an invariable initial profile of the channel,as the tidal range increases,the equilibrium scour depth of the channel also increases,indicating that tidal range has a significant influence on the scour depth;（3） with an invariable tidal range,as the longitudinal bed slope of the channel increases,the scour depth decreases,indicating that the bed slope also affects the final equilibrium state.