AbstractInduced by velocity shear, Kelvin-Helmholtz (KH) instability arises along an interface of two different fluids. In stratified flows, the KH instability is the first step toward to the onset of intensive mixing in the pycnocline, and it has been thought to be the main mechanism of converting stratified fluids to mixing (Geyer et al., 2010). The direct observation of KH instability in ocean is rare, and a few observations in estuarine and coastal areas are obtained by analyzing the acoustic backscatter profiles from echo sounder. However, the backscatter can only provide qualitative images of the KH billows, which cannot well represent the evolution and influence of KH billows on surrounding density field. Well treatment of vertical variability of velocity and density, non-hydrostatic model is a new and useful tool for the study of K-H instability. In this study, we established a non-hydrostatic model along the North Passage of Yangtze River Estuary to explore the occurrence of KH instability in the domain.
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