论文标题
固定流动的小球体上的惯性扭矩
Inertial torque on a small spheroid in a stationary uniform flow
论文作者
论文摘要
各向异性颗粒在流动中的旋转和正向如何取决于它们所经历的流体动力扭矩。在这里，我们通过数值求解Navier-Stokes方程来计算在均匀流中作用在均匀流中的小球体上的扭矩。粒子的形状与植物（宽高比$λ= 1/6 $）变化，以划分（$λ= 6 $），我们考虑低和中等的粒子雷诺数（$ {\ rm re} \ le 50 $）。我们证明，扭矩的角度依赖性在理论上预测了小粒子雷诺数的数字在质量上保持正确的雷诺数数字，最高为$ {\ rm re} \ sim 10 $。但是，扭矩的幅度小于理论预测，随着$ {\ rm re} $的增加，扭矩的幅度越大。对于大于$ 10 $的重新，流过的球体会获得更复杂的结构，从而导致系统偏离理论预测。总体而言，我们的数值结果提供了有关在湍流中沉降的冰结晶方向统计的最新理论的理由。
How anisotropic particles rotate and orient in a flow depends on the hydrodynamic torque they experience. Here we compute the torque acting on a small spheroid in a uniform flow by numerically solving the Navier-Stokes equations. Particle shape is varied from oblate (aspect ratio $λ= 1/6$) to prolate ($λ= 6$), and we consider low and moderate particle Reynolds numbers (${\rm Re} \le 50$). We demonstrate that the angular dependence of the torque, predicted theoretically for small particle Reynolds numbers remains qualitatively correct for Reynolds numbers up to ${\rm Re} \sim 10$. The amplitude of the torque, however, is smaller than the theoretical prediction, the more so as ${\rm Re}$ increases. For Re larger than $10$, the flow past oblate spheroids acquires a more complicated structure, resulting in systematic deviations from the theoretical predictions. Overall, our numerical results provide a justification of recent theories for the orientation statistics of ice-crystals settling in a turbulent flow.
