Two-dimensional tide-induced residual sand transport: Applications to the Jiangsu coast, China. (30th October 2020)

• Record Type: Journal Article
• Authors: Du, Zhiyun; Yu, Qian; Wang, Yunwei; Peng, Yun; Zhu, Qingguang; Wang, Ya Ping
• Is Part Of: Estuarine, coastal and shelf science. Volume 245(2020)
• Publication Date: 2020-10-30
• Subjects: Residual sand transport -- Tidal environment -- Analytical solution -- Jiangsu coast; Estuarine oceanography -- Periodicals; Coasts -- Periodicals; Estuarine biology -- Periodicals; Seashore biology -- Periodicals; Coasts; Estuarine biology; Estuarine oceanography; Seashore biology; Periodicals; 551.461805
• DOI: 10.1016/j.ecss.2020.106991
• Languages: English
• ISSNs: 0272-7714

Abstract

Abstract: The residual sand ( D > 62.5 μm) transport (RST) refers to the tidally averaged rate of horizontal sand transport. Albeit much smaller than the peak rates, it determines the morphological evolution. The analytical expression for the tide-induced RST has been reported in the condition of one-dimensional tidal currents by van de Kreeke and Robaczewska (1993). Here we extended the analytical solution to two-dimensional. The constituents of the residual, M2, and M4 tidal current velocities were used to characterize the collinear tidal current in the orthogonal X and Y directions, i.e., cross-shore and alongshore, respectively, while the M2 tidal constituent is dominant in both directions. Based on the solution, RST is controlled by a series of triple interactions of the M2 tidal velocity in the X direction, M2 tidal velocity in the Y direction, and the residual or M4 velocity in the X or Y direction. The solution was applied to the tide-dominated continental shelf of the Jiangsu coast, China, where the alongshore current is much stronger than the cross-shore component. The results show that the triple interactions of the cross-shore M2 tidal velocity ( U M2 ), the alongshore M2 tidal velocity ( V M2 ), and the alongshore residual velocity account for the major parts of both the alongshore and cross-shore RST in the nearshore area. The RST patterns promote sand accumulation in the shallow nearshore area and generate a narrow and active conduit of coastal alongshore sand transport. These findings can be applied in similar marine environments to understand the effects of non-linear tidal interactions in RST. Highlights: ● The mechanisms of two-dimensional tide-induced residual sand transport (RST) are revealed by the analytical solution. ● Interaction of the cross-shore M2, the alongshore M2, and the alongshore M0 accounts for the most part of RST in the nearshore area of the Jiangsu coast, China. ● The RST patterns promote sand accumulation in the shallow nearshore area and generate a narrow and active conduit of coastal alongshore sand transport.