Numerical simulation of hydrodynamics and mass transport in Zhifu Bay

To provide a reference for marine ecological protection and coastal engineering construction, the tidal field of Zhifu Bay of Yantai, Shandong, was constructed using the Mike21 HD model and particle tracking under the newest shoreline pattern. Result shows that the duration of rising and falling tides is uneven, and the tidal current velocity of the maximum ebb is greater than that of the maximum flood. The velocity on the northeastern bank is the largest, and decreases gradually towards the southwestern bank. In the north of the bay, the flow direction is opposite. In the middle and south of the bay, the flow direction is SW at the moment of flood and gradually turns from south to NW then turns clockwise to NE at the moment of ebb. The Euler residual flow field of 15 tidal cycles was calculated. The residual flow direction is a clockwise residual circulation centered in the northeast of the bay except for some areas towards the south coast. The residual flow velocity is slow on the whole, less than 0.06 m/s in most areas. Sixteen free particles were released equidistantly. The particle migration trajectories show that materials in the north of the bay was hard to move into the bay, and the free particles in the bay eventually migrated out of the bay. There was no aggregation of particles in the bay, indicating that the hydrodynamic condition of Zhifu Bay was conducive to moving materials out of the bay. The particles to the north of Danzi Island were transported eastward to the bay and then bypassed Danzi Island and other islands to the open sea to the southeast. The particles to the south of Danzi Island whirled and oscillated in the bay, and finally moved southward in a ∞-shaped trajectory.