Effect of the buoyant force on the incipient motion of soil particles on sloping beds.

摘要

The buoyant force can be affected in direction and magnitude due to the water flow on steep slopes. Consequently, the longitudinal slope correction factor (taucr slope/taucr horizontal ) for incipient motion may change too. This current study performed an experimental procedure to evaluate it and compared it with theoretical approaches such as the physical equation derived by Zapata (1987) to include this buoyant force effect.;The experimental slope correction factor obtained from the experiment does not completely agree with the existing sediment transport theory. Scarcity of available sediment to be transported by an armoring effect during the experimental procedure and limitations on measurement instrumentation are the probable causes of this disagreement. Sensitivity analysis of taucr showed that this parameter is more sensitive to variation of tau0s values than the sediment load qs. Zapata's and classical approach equations predicted better results than Ulrich equation for the taucr slope/taucr horizontal but buoyant force effect on the incipient motion of soil particles cannot be evaluated due to the observed lower energy slope values epsilon. (Abstract shortened by UMI.)