Numerical Simulation Of Dynamic Geomorphic Features Of Two Types Of Estuaries

The numerical model of the evolution of estuarine dynamic geomorphology is established.The hydrodynamic equation and the sediment transport equation are solved by ADI scheme.The terrain evolution equation is discretized by the fifth order accuracy WENO method which is used to solve the evolution equation of the underwater topography.We have made the hydrodynamic numerical calculation of the existing examples using Mike21 commercial software.And the results of the hydrodynamic simulation are validated by the model.The sediment concentration of the Yellow River estuary was simulated by using the sediment transport model and compared with the measured data of the Yellow River estuary.The ideal-type estuarine terrain evolution model is used to simulate the evolution process of two-dimensional estuarine sand.The results of the simulation were compared with the results of the two-dimensional elliptical shoal evolution of the estuaries.It is proved that the model can be used to simulate the formation and evolution of dynamic features of estuaries.The effects of river runoff,sediment transport,tidal level and estuarine coastline boundary conditions on estuarine terrain are discussed respectively.The Yellow River mouth is a typical representative of the outer convex type estuary.The morphology of the Yellow River estuary presents a variety of estuarine and morphological features.Using the numerical simulation to reproduce the process of the evolution of these features which further deepens our understanding of the evolution of the geomorphic features of delta-type estuary.Based on this model,the geomorphic characteristics evolution process of the Yellow River estuary area from May 1984 to September 1988 was simulated.The results reproduced the two forms of the Yellow River mouth(the type of double-lobe and single channel and the type of doublechannel and single lobe).These further deepen our understanding of the evolution of delta-type estuary features.The Fly River estuary in Papua New Guinea is a typical concavity.This article takes the Fly River estuary as an example.The calculation model was boiled according to the actual size of the Fly River estuary.The terrain evolution process of the Fly River estuary area under the influence of runoff and tidal current is analyzed.And the effects of runoff velocity 0.4m/s0.7m/s and 1.0m/s on the terrain evolution of the delta harbor are selected respectively.The corresponding increase of the flow rate shows that the topography of the shoal is increased and the ridge erosion is deepened,which increases the speed of terrain evolution.The effectsof the plane shape of the estuary on the terrain evolution of the delta estuary are studied respectively.We have a deeper understanding of the evolution of the dynamic characteristics of the concave estuary.