DNS of Taylor-Couette flow between counter-rotating cylinders at small radius ratio
DNS of Taylor-Couette flow between counter-rotating cylinders at small radius ratio
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小半径比反向旋转圆柱体之间 Taylor-Couette 流动的 DNS
DOI：
10.1007/s12572-018-0217-x
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发表时间：
2018
影响因子：
0.9
通讯作者：
Takahiro Tsukahara
中科院分区：
文献类型：
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作者：
Ryo Tanaka;Takuya Kawata;Takahiro Tsukahara
采用三维直接数值模拟的方法，研究了半径比为-0.5的反向旋转泰勒-库埃特流动在很宽的雷诺数范围内从层流到湍流的变化。我们研究了流动结构的依赖性，并确定了一个临界值，在0.3和0.3之间，低于该临界值，稳定的外圆柱侧表现出的模态结构，这是不同于泰勒涡流的内侧。在点处，不稳定内侧的泰勒涡控制了整个柱间流场，其足迹在外柱壁附近观察到。然而，对于，从内侧的影响是有限的圆柱间隙的中心。此外，在稳定的外圆柱侧，出现了一个模态结构，轴向均匀，方位角周期性，和类似的Tollmien-Schlichting不稳定波。随着雷诺数的增加，壁单元内的模态结构的方位波数发生变化，径向增厚。虽然外侧的雷诺剪应力保持近似为零，但速度波动的强度与中心部分的泰勒涡流相当。
A counter-rotating Taylor–Couette flow with relatively small radius ratios of–0.5 was investigated over a wide range of the Reynolds number, from laminar to turbulent regime, by means of three-dimensional direct numerical simulations. We investigated thedependence of the flow structure and determined a critical value betweenand 0.3, below which, the stable outer cylinder side exhibited a modal structure that was different from the Taylor-vortex flow on the inner side. At, the Taylor-vortex on the unstable inner side dominated the entire flow field between the cylinders, whose footprints were observed in the vicinity of the outer cylinder wall. However, for, the influence from the inner side was limited up to the centre of the cylinder gap. Moreover, on the stable outer cylinder side, there appeared a modal structure that was axially homogeneous, azimuthally periodic, and similar to the Tollmien–Schlichting instability wave. As the Reynolds number increased with a fixed, the modal structure changed its azimuthal wavenumber and thickened radially in the wall unit. Although the Reynolds shear stress on the outer side remained approximately zero, the intensity of the velocity fluctuations was comparable to the Taylor-vortex flows in the central part.