Centrifugal instabilities during spin-down to rest in finite cylinders. Numerical experiments
Centrifugal instabilities during spin-down to rest in finite cylinders. Numerical experiments
复制标题
旋转下降到有限圆柱体中时的离心不稳定性。
DOI：
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发表时间：
1981
影响因子：
3.7
通讯作者：
S. H. Davis
中科院分区：
文献类型：
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作者：
G. Neitzel;S. H. Davis
一个充满粘性不可压缩流体的圆柱体处于刚体绕其对称轴旋转的初始状态。如果容器被冲激静止，则由于离心力和压力梯度力之间的不平衡，所产生的非定常自旋向下流动可能会受到侧壁不稳定的影响。利用有限差分模拟对轴对称Navier-Stokes方程进行数值模拟，对各种展弦比和雷诺数进行积分，对这些不稳定性进行数值检验。计算了Taylor-Görtler涡旋波长谱、转矩和角动量历史。给出了不稳定开始时间和自旋停止时间的判据。讨论了不稳定引起的混合增强对旋降特性和转矩的影响。结果与实验结果进行了比较。
A cylinder filled with a viscous, incompressible fluid is in an initial state of rigid-body rotation about its axis of symmetry. If the container is brought to rest impulsively, the resulting unsteady spin-down flow may be subject to sidewall instabilities due to an imbalance between centrifugal and pressure gradient forces. These instabilities are examined numerically using a finite-difference simulation to integrate the axisymmetric Navier–Stokes equations for a variety of aspect ratios and Reynolds numbers. The Taylor–Görtler vortex-wavelength spectrum, the torque and the angular momentum histories are calculated. Criteria for the onset time for instability and the spin-down time are given. The effects of the enhanced mixing due to instability on the spin-down characteristics and torque are discussed. The results are compared with experiment.