Influence Of Coastal Current On Topographic Evolution Of Yellow River Delta

In this paper,continuous equation,momentum equation considering radiation stress and wave energy equation coupling are applied to establish a hydrodynamic model considering the influence of wave and tidal current at the same time.ADI format is used to solve it discretely.Then Soulsby sediment transport rate formula is used to establish sediment transport model.Finally,terrain evolution calculation model is established using terrain evolution equation and WENO format is used to solve it discretely.In order to verify the correctness of the model,this paper verifies the hydrodynamic model by comparing with the previous experimental results and measured data,verifies the sediment transport model by comparing with the analytical solution,and verifies the terrain evolution model by comparing with the results of MIKE21,which proves that the model adopted in this paper is correct.In order to study the influence of individual hydrodynamic forces on the topography of the Yellow River Delta,this paper uses the measured water depth data of the Yellow River Delta in 1996 as the simulated topography,and takes representative wave,runoff,tidal current and aeolian residual inflow and outflow boundary conditions to simulate the evolution characteristics of the flow field and topography of the Yellow River Delta under the action of individual wave,runoff,tidal current and residual current in the three years since the change of branch in 1996.In order to study the influence of coupled hydrodynamic forces on the topography evolution of the Yellow River Delta after the addition of coastal currents,this paper still takes the topography in 1996 as an example,takes the incident conditions of waves,runoff and tidal current in the previous part,explores the flow field characteristics and topography evolution law when waves and runoff,waves and tidal current are coupled,and compares the results with the separate hydrodynamic results in the previous paper to explore the contribution of coastal currents.In order to study the topographic evolution law of the Yellow River Delta before and after the artificial branching,this paper establishes calculation models based on the measured water depth of the Yellow River Delta in 1990 and 1996 respectively,and sets the boundary runoff velocity and suspended sediment concentration based on the inflow and sediment data of the estuary in the calculated years,respectively,to simulate the flow field and topographic evolution of the Yellow River Delta from 1990 to 1995 and from 1996 to 1999.The results show that the coastal current is the main cause of coastal erosion on the wave-facing side.The runoff and suspended sediment concentration determine the scouring and silting patterns of the estuary.The tidal current has strong scouring effect on the area south of the old estuary and promotes the coastal erosion in the north.