Direct numerical simulation of moderate-Reynolds-number flow past arrays of rotating spheres
Direct numerical simulation of moderate-Reynolds-number flow past arrays of rotating spheres
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DOI：
10.1063/1.4927552
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发表时间：
2015-07
影响因子：
4.6
通讯作者：
Qiang Zhou;L. Fan
中科院分区：
文献类型：
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作者：
Qiang Zhou;L. Fan
直接数值模拟浸没边界格子Boltzmann方法被用来研究在中等颗粒雷诺数下，颗粒旋转对流过单分散球随机阵列的流动的影响。本研究是作者[Q. Zhou和L.- S. Fan，“Direct numerical simulation of low-Reynolds-number flow past arrays of rotating spheres，”J. Fluid Mech.765，396-423（2015）]，其探索了在低颗粒雷诺数下颗粒旋转的影响。研究结果表明，当颗粒雷诺数小于50时，随着颗粒雷诺数的增加，归一化马格努斯升力迅速减小。对于颗粒雷诺数大于50，归一化的马格努斯升力接近一个恒定的值，是不变的固体体积分数。在本研究中，在低颗粒雷诺数下观察到的马格努斯升力对旋转雷诺数（基于球的角速度和直径）的比例依赖性不会改变，使得马格努斯升力成为另一个可能的因素，可以显着影响流体-颗粒流动的整体动力学，而不是阻力。此外，研究发现，归一化阻力和归一化扭矩都随着颗粒雷诺数和固体体积分数的增加而增加。最后，在任意固体体积分数，旋转雷诺数，和颗粒雷诺数的阻力，马格努斯升力，和扭矩随机阵列的旋转球体的相关性制定。
Direct numerical simulations with an immersed boundary-lattice Boltzmann method are used to investigate the effects of particle rotation on flows past random arrays of mono-disperse spheres at moderate particle Reynolds numbers. This study is an extension of a previous study of the authors [Q. Zhou and L.-S. Fan, “Direct numerical simulation of low-Reynolds-number flow past arrays of rotating spheres,” J. Fluid Mech. 765, 396–423 (2015)] that explored the effects of particle rotation at low particle Reynolds numbers. The results of this study indicate that as the particle Reynolds number increases, the normalized Magnus lift force decreases rapidly when the particle Reynolds number is in the range lower than 50. For the particle Reynolds number greater than 50, the normalized Magnus lift force approaches a constant value that is invariant with solid volume fractions. The proportional dependence of the Magnus lift force on the rotational Reynolds number (based on the angular velocity and the diameter of the spheres) observed at low particle Reynolds numbers does not change in the present study, making the Magnus lift force another possible factor that can significantly affect the overall dynamics of fluid-particle flows other than the drag force. Moreover, it is found that both the normalized drag force and the normalized torque increase with the increase of the particle Reynolds number and the solid volume fraction. Finally, correlations for the drag force, the Magnus lift force, and the torque in random arrays of rotating spheres at arbitrary solids volume fractions, rotational Reynolds numbers, and particle Reynolds numbers are formulated.