Kelvin-Helmholtz (K-H) instability plays a significant role in the transit from stratification to mixing in estuaries. To investigate the existence of K-H instability , the non-hydrostatic model NHWAVE is utilized to simulate the mixing process along the North Passage of the Yangtze River Estuary. Using high horizontal resolution, the structure of K-H billows have been successfully captured within the Lower Reach of the North Passage.
The K-H instability occurs between the max flood and high-water slack. The horizontal length scale of the instability is about 60m, which is comparable with the observations in other estuaries.