Lattice boltzmann simulation of flow over a transversely oscillating circular cylinder
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摘要: 基于格子Boltzmann方法(LBM)对不可压横向振荡圆柱绕流问题进行了数值研究. 与传统的求解宏观的N-S方程的数值方法不同, LBM求解此类问题不需要采用动网格, 而且不需要对网格进行特殊处理, 从而节约了计算成本. 结果显示, 当振荡频率增加到相应的静止圆柱绕流的自然涡脱落频率附近时, 圆柱后最新形成的集中涡距离柱体越来越近, 直到达到一个极限位置. 随后, 集中涡突然转向圆柱体另一侧脱落. 当振荡频率接近于静止圆柱的自然涡脱落频率时, 发生频率同步的现象. 随着振荡频率远离自然涡脱落频率, 同步现象消失. 在几种次谐振荡和超谐振荡下, 尾流区的涡脱落频率仍为相应的静止圆柱绕流的自然涡脱落频率.
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关键词:
- 升阻力
Abstract: The lattice Boltzmann method (LBM) is used to simulate the incompressible flow past a transversely oscillating circular cylinder. Simulations are conducted at Reynolds number $Re=185$. The results show that as the oscillation frequency of the cylinder is increased relative to the natural vortex shedding frequency of the corresponding stationary cylinder, the initially formed concentration of vorticity moves closer to the cylinder until a limiting position reaches. At this point, the vorticity concentration abruptly switches to the opposite side of the cylinder. When the oscillation frequency is near the natural vortex shedding frequency of a corresponding stationary cylinder, frequency synchronization occurs. When the oscillation frequency is away from the natural vortex shedding frequency, frequency synchronization also disappears. In several subharmonic and superharmonic excitation situations, vortex shedding frequency in the near wake region also equals to the natural one of the corresponding stationary cylinder.-
Key words:
- lift and drag
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