Kelvin-Helmholtz Billows Induced by Shear Instability along the North Passage of the Yangtze River Estuary, China

Kelvin-Helmholtz Billows Induced by Shear Instability along the North Passage of the Yangtze River Estuary, China

Blog Article

Kelvin-Helmholtz (K-H) instability plays a significant role in mixing.To investigate the existence of K-H instability along the North Passage of the Yangtze River Estuary, the non-hydrostatic model NHWAVE is utilized to simulate the fresh-salt water 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 Lunch Box between the max flood and high-water slack.

The duration and length scale of the K-H billows highly depends on the local interaction between fresh-water discharge and tide.The horizontal length scale of the instability is about 60 m, similar to the observations in other estuaries.In the vertical direction, the K-H billows exist within the pycnocline with length scale ranging from 6 to 7 m.The timescale of the billows is approximate 6 min.

By analyzing the changes of potential energy during the mixing process, results show that the existence of K-H instability induces intense vertical mixing, which can greatly increase mixing efficiency in the North Shower Benches Passage of the Yangtze River Estuary.