Author(s): Cong Xiao; Kiyosi Kawanisi; Mohamad Basel Al Sawaf
Linked Author(s): Kiyoshi Kawanishi
Keywords: Shallow-water acoustic tomography; Tidal channel junction; Tidal current; Residual current
Abstract: In a tidal channel network, there are many branches/junctions that are commonly bifurcated asymmetrically. Investigations of hydrodynamics at the tidal channel junction related to the interaction between the tidal wave s, upstream river discharge, and the geometrical shape of branches has been carried out. The Fluvial Acoustic Tomography (FAT) System developed by Hiroshima University is able to measure tidal currents in shallow waters and continuous visualize 2D flow pattern. Herein, the hydrodynamics of tidal junction are presented by an array of FAT system with numerical inversion schemes. The horizontal distributions of the tidal currents and the residual currents were well calculated by inverse analysis of FAT data. Although the salt -wedge intrusion had a strong effect on sound propagation patterns that led to a multitude of arrival times, the reconstructed flow patterns agreed favorably with ADCP data. Moreover, we analyzed the main dynamic processes responsible for the residual currents using the averaged horizontal momentum equation. The predominant terms in balancing the momentum equation of the residual currents are the advection of the tidal currents, the horizontal pressure gradient, and the horizontal mixing of the residual currents.