Study on Numerical Simulation of Flow around Body by MPS using Cluster System

本研究将现有的二维粒子法程序改为三维粒子法代码，并与实验结果和其他数值计算结果进行了比较，得到了较好的三维流场计算结果。通过展示本研究的各种数值计算结果，可以判断能够适应颗粒法的流体现象。(1)采用该方法模拟了突然移动的三维平板周围的流动。结果表明，MPS可以计算快速现象。(2)落物与水面碰撞时的喷雾现象。将三角柱抛下，模拟与水面碰撞时瞬间产生的喷雾现象。结果表明，与实验用高速相机拍摄的照片相比，两者具有较高的一致性。(3)落体与水面碰撞后的运动将六面体对角排出，模拟落体落到水面后的运动。结果表明，与实验结果相比，该模型与形状为六面体的物体具有质的一致性。(4)形状简单的三维旋转翼采用六面体作为旋转翼的机翼，进行了三维旋转翼的基本计算。在粒子法中，旋转翼的节距建模比较困难，但可以通过将无节距的原始形状变为带节距的形状来获得物理有效性。

An existing two-dimensional particle method program was originally changed to the three-dimensional particle method code by this research, and an excellent result was obtained about the following three-dimensional flow compared with the experiment result and other numerical calculation results.The fluid phenomenon that was able to adjust to the particle method could be judged by showing a variety of numerical calculation results of this research.(1)Flow analysis around 3-dimensional plate that moved suddenlyA transitional fluid phenomenon was simulated by this method.As a result, it was clear that rapid phenomenon can be calculated by MPS.(2)Spray phenomenon when surface of the water collides by falling objectA triangular pillar was dropped, and the spray phenomenon momentarily generated when colliding with the surface of the water was simulated.As a result, the agreement with high accuracy could be seen compared with the experimental photograph with a high-speed camera.(3)Movement after surface of the water collides of falling objectThe hexahedron was diagonally discharged, and the fall to the surface of the water and the movement afterwards were simulated.As a result, a qualitative agreement was seen compared with the experiment result with the object with shape that looked like the hexahedron.(4)Three-dimensional rotational wings with simple shapeA basic calculation of the three-dimensional rotation wing was executed by using the hexahedron for the wing of the rotational wing.Physical validity could be obtained by changing to the shape with pitch from original shape without pitch although it was difficult to model the rotational wings with the pitch in the particle method.