Development of three-dimensional vortex method for bubbly jet and parallel computing system

(1)三维涡旋法并行计算系统的开发构造了一种并行计算方法。它是基于并行虚拟机的。8台个人计算机通过交换集线器连接。将该系统应用于本文的计算，实现了计算的高速化。(2)矩形圆柱体的泡状流计算为了验证涡旋法的有效性，对矩形圆柱体向上的泡状流进行了数值模拟。模拟结果表明，气泡被卷吸到卡门旋涡中，旋涡脱落频率低于单相流。气泡羽流的计算用涡旋法模拟了气泡在储罐内上升时产生的气泡羽流。结果表明，上升气泡周围出现了大尺度的旋涡，诱导水流速度满足相似分布。同时也证实了羽流的波长和幅度与测量结果吻合得很好。

(1) Development of parallel computing system for three-dimensional vortex methodA parallel computing method is constructed. It is based on the Parallel Virtual Machine. Eight personal computers are connected through a switching hub. When applying the system to the present computation, the high-speed computation is realized(2) Computation of bubbly flow around a rectangular cylinderTo verify the validity of the vortex method, the upward bubbly flow around a rectangular cylinder is simulated. The simulation demonstrated that the bubbles are entrained into the Karman vortex and that the vortex shedding frequency is lower than that for the single-phase flow. These results are favorably compared with the corresponding experiment.(3) Computation of bubble plumeThe bubble plume, induced by the bubbles rising in a tank, is simulated by the vortex method. It is found that large-scale vortices appear around the rising bubbles and that the induced water velocity satisfies the similarity distribution. It is also confirmed that the wavelength and amplitude for the plume agree well with the measured results.