Fig. 1

Study area and location of monitoring stations. Triangles indicate the location of tidal monitoring stations; circles indicate the location of tidal stations; grey areas are land; white areas are sea"

Fig. 2

Luoyuan Bay topography and computational domain grid"

Fig. 3

Tide level verification results. The "+" symbol in the graph represents the measured tide level and the curved line represents the simulated value of the tide level"

Fig. 4

Verification results of flow rate and direction. The “+” in the graph represents the measured value of the flow rate or direction and the curved line represents the simulated value of the flow rate or direction"

Fig. 5

Flow field distribution during rising and falling times of the Luoyuan Bay. (a) Surface flow field at rise; (b) bottom flow field at rise; (c) surface flow field at fall; (d) bottom flow field at fall. The direction of the arrow in the diagram indicates the direction of flow at that point, and the length of the arrow indicates the magnitude of the flow velocity. The triangle shows the reference point for the velocity, and the lower right side shows the tidal variation at this point, where the horizontal axis at the dot is the time of rise and fall"

Fig. 6

Zoning of the Luoyuan Bay, location of Lagrangian particle release and setting of vertical cross-sections. The dots in the diagram show where the Lagrangian particles are placed, the lines with horizontal bifurcations show the boundaries of the different partitions, and the red arrows show the location of the vertical sections"

Fig. 7

Comparison of vertical flow velocities at various transects in the Luoyuan Bay. (a) Vertical flow velocity at the Komen Channel section; (b) vertical flow velocity at the north-western section of the bay; (c) vertical flow velocity at the south-western section of the bay. The top and bottom sides of the three subplots represent the distribution of vertical velocity at the time of rise and fall, respectively. The arrows on the graph indicate the direction of flow and the colored fills indicate the vertical flow values. The horizontal and vertical coordinates are the cross-sectional width and depth, respectively (unit: m)"

Fig. 8

Distribution of Eulerian residual flow field in the Luoyuan Bay. (a) the surface layer; (b) the bottom layer; The direction of the arrow in the diagram indicates the direction of the residual flow at that point, and the length of the arrow indicates the size of the residual flow"

Fig. 9

Transport trajectories of partial Lagrangian particles in region I"

Fig. 10

Transport trajectories of partial Lagrangian particles in region Ⅱ"

Fig. 11

Transport trajectories of partial Lagrangian particles in region Ⅲ"

Fig. 12

Distribution of net particle transport distance. The blue filled area in the figure indicates the 15-day net transport distance of the particles, the red line and the ring of arrows indicate the apparent residual flow ring in the bay, and the shaded area indicates the 'stagnant' area in the bay"