Turbulent Mixing and Turbulent Events in Breaking Bores

A breaking tidal bore is a highly turbulent transient process, that may affect the natural estuarine system. Like many natural process flows, the tidal bore flow motion is dominated by coherent structure activities and turbulent events, with significant impact in terms of sediment processes. Herein an unsteady turbulent event analysis was developed for highly-unsteady rapidly-varied breaking bore flows. New experimental data were collected in a large size facility under controlled flow conditions. The data analysis was based upon basic concepts, in which turbulent bursting events were defined in terms of the instantaneous relative turbulent flux, and applied to the rapidly-varied highly-unsteady bore motion. The results are compared with recent field observations (Leng et al. 2018). The results showed that the turbulent event analysis provided valuable quantitative details into the turbulent bursts that are responsible for major mixing and sedimentary processes.