Hydraulic Phenomena Accmpanied with Driftwood

建立了浮木进入水平二维流场时的流场数值模拟模型，计算了浮木进入水平二维流场时，由于房屋之间或房屋前方的堵塞，浮木的行为及其堵塞过程。浮木的旋转运动方程的动态评估的拉格朗日形式以及平移运动方程。计算采用欧拉流体方程和拉格朗日浮木方程的相互作用组合，并随机给出了浮木的湍流扩散系数和旋转角速度。计算结果很好地解释了实验中一组浮木的位置、旋转角度以及在房屋之间和/或房屋前停留的浮木数量随时间的变化。此外，通过实验发现，筑坝会增加木屋被冲走的风险。

A numerical simulation model has been developed for computing the behavior of driftwood and its dam up process due to jamming between and/or in front of the houses when driftwood debouches into horizontally two-dimensional flow field. Equations of rotational motion of driftwood is evaluated dynamically in the Lagragian form as well as equation of translational motion. The calculation was accomplished by an interacting combination of Eulerian fluid and Lagragian driftwood equations, in which a trubulent diffusivity and rotational angular velocity of the driftwood were also stochastically given. The positions, rotational angles in a group of driftwood, and time change of the number of stopped driftwood between and/or in front of the houses in the experiments are well explained by the calculation. Moreover, the risk of swept away of wooden houses found to be increased by the dam-up experimentally.