Author(s): Yiping Li; Jin Wei; Kumud Acharya
Linked Author(s):
Keywords: No Keywords
Abstract: Coherent motions play a significant role in sediment resuspension, which is an important cause of eutrophication in Lake Taihu. The general approach in detecting coherent motions in wall turbulence is condition sampling methods, among which the quadrant splitting method is the most popular. When the inspection is conducted by condition sampling methods, one or two parameters are set by empiricism, e. g. parameter H in quadrant splitting. To eliminate the erroneous detection caused by empirical parameter in identifying coherent motions, this research combines autocorrelation function and quadrant splitting to determine objective values of parameter H under different wind disturbances at three typical sites of Lake Taihu. The results showed that the value of parameter H was comparatively stable (0.72-1.28). However, the calculation results of momentum and sediment resuspension fluxes were very sensitive to this parameter: in that an increase of 0.56 in H value led to a decrease of 10.7% -24.1% in the stress fraction and 14.7% -26.5% in the sediment resuspension flux fraction, respectively. Taking one fixed empirical value for H is unsuitable for Lake Taihu, the objective values of H should be determined by the above-mentioned method that can also be applied in other condition sampling methods and study regions.
Year: 2018