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基于紊流理论和射流冲刷机理,本文提出了二维垂向射流冲刷的数学模型.以拖曳力为主要参变数,导出了基于希尔兹数的推移质泥沙输运模型,将临界希尔兹数作为泥沙颗粒起动的判别标准,模型中没有考虑悬移质的运动,推移质运动所引起的河床形态变化用动网格技术来描述,从而形成了基于动边界的二维射流冲刷数学模型.针对二维垂向射流清水冲刷进行了试验研究,得出了射流流态及冲刷坑的几何特征等资料.选用实验室物理模型参数对二维射流冲刷进行了数值计算,试验和数值模拟均展现了射流冲刷摆动的发展过程,两者给出的射流摆动现象的良好吻合验证了模型和算法的有效性,进而在计算和试验研究基础上给出了射流冲刷平衡时冲刷坑特征长度的半经验公式.
Based on turbulence theory and jet scouring mechanism, a mathematical model of two-dimensional vertical jet scouring is proposed in this paper.Due to drag force as the main parameter, a model of sloppy sediment transport based on Shields’ As a criterion for determining the start of sediment particles, the model does not consider the motion of suspended matter, and the bed morphological changes caused by thrusting motion are described by moving grid technique, thus forming the two-dimensional jet erosion mathematical Model.For two-dimensional vertical jet clean water scouring experiments were carried out, and the jet flow state and scouring pit geometric characteristics and other data were obtained.Numerical calculations, experiments and numerical simulation of two-dimensional jet scouring were performed using laboratory physical model parameters Both show the development process of jet scouring wobble. The good coincidence of the jet oscillating phenomena proves the validity of the model and the algorithm. Then based on the calculation and experimental study, the characteristic length of the scouring pit in jet scouring equilibrium is given Semi-empirical formula.