The3D Numerical Simulation Of Flow Patter Based On Scour Of Spur Dikes

Among the various means of transport, the waterway transport has significantvantages like lower energy consumption, long transport distance and greattransportation amount. The development of waterway transport is quite necessary. As arenovating building, the spur dike has a very wide range of applications. It has apositive effect in contract the river bed, stabilize the river bank, adjust the flow patternand change the sedimentary transportation. However, concluding the previouslyinformation can found a part of spur dikes was damaged because of the erosion of thehead of spur dike, so this is always necessary to research the development of the scourhole. Before researching the development of the scour hole, it is necessary to find howthe stream flow in the scour hole. Based on this, the RNG k~ε three-dimensionalturbulent flow model used in this paper to simulate the stream in the scour hole. It iswell known that a good calculation modern can improve the accuracy of calculationwhen calculate the numerical simulation. This paper mainly focuses on researching andanalysis on three issues:①Water movement in the scour hole. Because the spur dike prevent water whenwater flows into the scour hole, the flow rates greater than the initial velocity. Form theplane of spur dike to observation, water flow with clockwise. At the same time,produced a number of secondary Eddies in the hole, according to the flow conditions,Eddies’ number, size and location are different. Because of effects of water flow, thesize and distribution of wall shear stress are not same in the wall of hole.②For studying the process of the scour hole development, the research focusedon effects of the water depth, initial velocity and the hole depth. Three dimensionalmodel’s results can be seen, Helical flow Vortex and secondary Eddies increase withincreasing water depth within a certain range, once beyond the certain depth, this rolewill be weakened. Higher initial velocity effect on flow patterns within the scour holeand turbulence intensity are growing in the scour hole. In the scour pit early stages ofdevelopment, velocity and turbulent kinetic energy intensity increase with increasingthe size and depth of the pit, once more than balance of size and depth, the flow velocityand turbulent kinetic energy intensity reduction.③Formula of scour hole depth. From mechanical perspective, which is thegreater between shear stress of water used for hole and critical shear stress of sediment depend the scour hole being scour, if it is greater than the critical shear stress sedimentwill be start, the scour hole was washed. Pursuant to the preceding analysis on influencefactors of influent to scour hole depth, to simple derivation these influencing factors andconcluded the formula that between deep pit and water depth ratio and Froude, andfinally using mathematical model calculated values the results of fitting a combinationof algebraic formula.