论文标题
实验和数值模拟的湍流中底部重杆的旋转动力学
Rotational dynamics of bottom-heavy rods in turbulence from experiments and numerical simulations
论文作者
论文摘要
我们成功地在中性不对称颗粒的湍流流动中成功执行了三维跟踪，这些粒子是中性构建和底部较重的，即它们沿其对称轴具有非均匀的质量分布。我们通过实验表明，微小的质量不均匀性如何影响沿首选垂直方向的粒子取向并改变其翻滚速率。基于现实的Navier-Stokes湍流和点状粒子模型的一系列模拟，可以探索以重力扭矩稳定性数和粒子纵横比比探索的完整参数空间范围。我们提出了一个理论扰动预测，在高底部体系状态下有效，与观察到的优先取向和颗粒的滚滚速率非常吻合。我们还表明，翻滚速率的概率分布函数的重尾形形状受颗粒的底部体重的影响较弱。
We successfully perform the three-dimensional tracking in a turbulent fluid flow of small asymmetrical particles that are neutrally-buoyant and bottom-heavy, i.e., they have a non-homogeneous mass distribution along their symmetry axis. We experimentally show how a tiny mass inhomogeneity can affect the particle orientation along the preferred vertical direction and modify its tumbling rate. The experiment is complemented by a series of simulations based on realistic Navier-Stokes turbulence and on a point-like particle model that is capable to explore the full range of parameter space characterized by the gravitational torque stability number and by the particle aspect ratio. We propose a theoretical perturbative prediction valid in the high bottom-heaviness regime that agrees well with the observed preferential orientation and tumbling rate of the particles. We also show that the heavy-tail shape of the probability distribution function of the tumbling rate is weakly affected by the bottom-heaviness of the particles.
