裂流和海岸环流引起的海岸变形特征研究

本项目研究裂流和海岸环流流场引起的海岸变形特征。所研究的裂流和海岸环流流场包括三类：一是海岸交叉波浪场产生的；二是沙坝或者平坡地形上沿岸方向变化的地形扰动产生的；三是风暴波况海岸交叉波浪场产生的。项目将研究海岸上这三类流场所引起的海岸变形特征，可以预见的这三类流场所产生的海岸变形分别是: (1)尖角型岸线变形; (2)海岸横向、倾斜沙坝系统，韵律型海岸沙坝，韵律型岸线;(3)类似尖角型的海岸侵蚀三维变形。本项目将研究这些海岸变形所产生的动力机制，包括强迫响应机制和地形不稳定机制，研究这些海岸变形发生的波况条件和地形条件。研究以物理模型实验，数值模拟和理论分析相结合的方式展开，探讨裂流和海岸环流流场引起的海岸变形所产生的形态特征和动力机制，探讨风暴波况裂流和海岸环流引起的海岸侵蚀变形的三维特征。

The present project studies the features of beach topography deformation induced by rip currents and coastal circulations. The flow field considered includes: (1) that produced by crossing waves; (2) that produced by topography perturbation on bar crest and beach bottom; (3) that produced by crossing wave field under storm wave condition. The corresponding beach topogrphy deformation patterns which can be expected and to be studied by the present project include: (1) the shoreline with large cusps; (2）transverse,oblique sand bars connected to shoreline, rhythm sand bar and rhythm shoreline; (3) three dimension shoreline erosion patterns with large cusps. The two mechanisms for beach deformation, the forced response and the topogrphy instability, and the three dimensional beach erosion patterns during storm condition will be examined.The research will be performed by conducting physical experiemnts, numerical simulations and theoretical analysis based on the linear topography instability theory. The phase-resolved numerical model and phase-averaged numerical model for computing the coupling between fluid flow and bottom deformation will be established in the study.