Characterizing elastic turbulence in the three-dimensional von Kármán swirling flow using the Oldroyd-B model
Characterizing elastic turbulence in the three-dimensional von Kármán swirling flow using the Oldroyd-B model
复制标题
使用 Oldroyd-B 模型表征三维冯卡门旋流中的弹性湍流
DOI：
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发表时间：
2022
期刊：
影响因子：
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通讯作者：
H. Stark
中科院分区：
文献类型：
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作者：
R. van Buel;H. Stark
我们提出了一个全面的三维数值研究的两个平行板之间的vonKármán旋流使用Oldrophil-B模型和特征的弹性湍流的发生和发展。我们用二次流强度来量化流动状态，二次流强度是速度波动的平均强度的量度，然后将序参量定义为二次流强度的时间平均值。序参数显示了从层流到弱混沌流和弹性湍流之间的亚临界过渡。在临界Weissenberg数[公式：见正文]处，发生向湍流的转变。在弹性湍流状态下，我们观察到速度波动和流动阻力的强烈增加，我们将其定义为对流体执行的总工作。在湍流状态下开始模拟并随后将[公式：见正文]降低到其临界值以下时，我们观察到序参量和流阻的滞后行为，这是亚临界转变的常见特征。在实验中也发现了滞后现象。此外，我们发现幂律标度的空间和时间的速度波动的功率谱，弹性湍流的特性。在我们的模拟中，幂律指数的最大值是时间指数的[公式：见正文]和空间指数的[公式：见正文]，它们非常接近实验中获得的值。
We present a comprehensive three-dimensional numerical investigation of the von Kármán swirling flow between two parallel plates using the Oldroyd-B model and characterize the onset and development of elastic turbulence. We quantify the flow state with the secondary-flow strength, a measure of the average strength of the velocity fluctuations, and then define an order parameter as the time average of the secondary-flow strength. The order parameter displays a subcritical transition from the laminar to a bistable flow that switches between weakly chaotic flow and elastic turbulence. The transition to the bistable flow occurs at the critical Weissenberg number [Formula: see text]. In the elastic turbulent state, we observe a strong increase in velocity fluctuations and flow resistance which we define as the total work performed on the fluid. Upon starting simulations in the turbulent state and subsequently lowering [Formula: see text] below its critical value, we observe hysteretic behavior in the order parameter and the flow resistance, which is a common feature of a subcritical transition. Hysteresis has also been found in experiments. Additionally, we find power-law scaling in the spatial and temporal power spectra of the velocity fluctuations, a characteristic for elastic turbulence. The maximum values of the power-law exponents in our simulations are [Formula: see text] for the temporal exponent and [Formula: see text] for the spatial exponent, which are remarkably close to the values obtained in experiments.
影响因子：
3.1
作者：
Gutierrez-Castillo, Paloma;Thomases, Becca
通讯作者：
Thomases, Becca
影响因子：
3.1
作者：
E. Shaqfeh;B. Khomami
通讯作者：
E. Shaqfeh;B. Khomami
影响因子：
4.6
作者：
Kumar, Manish;Ardekani, Arezoo M.
通讯作者：
Ardekani, Arezoo M.