Study On The Fluvial Process And Bed Resistance Of Sand Straight Channel Downstream Reservoir

Lots of reservoirs have been formed in the river to meet the demand. As the reservoir plays efficiency, it changes the river natural attribute, such as intercepting the incoming water and sediment, breaking the existing balance of the river downstream and so on, which makes the flow to stay in saturation state for a long time and the river bed to scour and coursing. All these will affect the flood control, shipping, water intaking, ecosystem etc. Thus, many researchers studied the fluvial process of river downstream reservoir, but the special studies about straight channel downstream reservoir are few and lack of systematic. And the straight channel is a basic river pattern, which is the basis to study the other channels. Therefore, it is essential to study the fluvial process and bed resistance of sand straight channel downstream reservoir.The paper firstly summarized the advances of the fluvial process and bed resistance of channel downstream reservoir. And then, the author studied the hydrodynamic turbulence characteristics, the fluvial process in different marginal banks and flow conditions, the resistance characteristics and the relationship between resistance and bed geometry by generalized model and theoretical analyses. Finally, the author draws the conclusions as follows:(1) The time-averaged velocity in lengthwise direction is linked with marginal bank, and presents the trend that the velocity of beachhead is the smallest, and that of middle bank and beach tail are near. Flow direction of the time-averaged velocity in transverse direction changes periodically under the influence of marginal bank. The relative turbulence intensity at bank is the largest, and that near the bank is the smallest.(2) The water surface profile presents the trend from decreasing to increasing, and the more the bank number is, the larger the final gradient is. The head and middle of the bank is mainly scouring, and the former is severe, while deposition can be seen at the tail of the bank.(3) The comprehensive resistance force increases in the last stage, and finally reaches a stable value. The more the bank number is, the larger the comprehensive resistance force increases. And it increases with the initial Fr and width-depth ratio increasing and the Re decreasing.(4) The fractal dimension and resistance force have positive correlation.