Upstream Local Scour Of Low-head Hydro-junction

With the continuous development of social, economic and population growth, water and electricity requirements are increasing year by year. But high-head water the resources have less and less , water resources development in low-head hydropower development as another important direction.Different of high-head hydro, low-head hydro don't have no capacity of adjusted peak or the resistance scour capability is weak. during the flood, we need open the gate to discharge flood by the gate-schedule. The origin,form prediction and protective measures of low-head hydro local scour research is necessary. This paper study of local scour, mainly the from of gate flow structure and the composition of riverbed by the combining of moving bed and fixed bed model test method, conducts generalized model experiments.The research results shows: First, while section gate discharges, the flow in front of adjacent block gate is blocked by gate, the flow velocity is transited from vertical to horizontal and dive in the front of gate and forms a vortex, the flow presents complex three-dimensional flow pattern, Agitation of kinetic energy increases, thus causing the bed surface sediment to start up and forming scour. Second, hydraulic conditions and sediment conditions under the condition of invariable at the border are the main factors influencing scour. Flow only affect the scour pattern but not scour position; Sediment particle size affects both scour pattern and scour position. Within a certain range, scouring depth increases rapidly with froude mumber increasing , beyond a certain froude number, scour depth increasing speed slows with froude number increasing. Third, based on experimental data, Based on experimental data, through the dimensional analysising and multiple regression theoretical analysising forecasts formula of sluice local scour depth, provide reference for engineering design. Fourth, through the ripped-rock, arranging protects jotham and other protective measures improves the riverbed capability resistance scour,Gate reasonable dispatch and another improving the flow condition measures can effectively solve local scour problems of the front of discharge sluice.