Numerical simulation of the swirling flow of a finitely extensible non-linear elastic Peterlin fluid
Numerical simulation of the swirling flow of a finitely extensible non-linear elastic Peterlin fluid
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DOI：
10.1063/5.0021469
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发表时间：
2020-10
影响因子：
4.6
通讯作者：
Krishna T. Khambhampati;R. Handler
中科院分区：
文献类型：
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作者：
Krishna T. Khambhampati;R. Handler
粘弹性流体已经被证明即使在非常低的雷诺数下也会经历不稳定性，并且这些不稳定性可以引起称为弹性湍流的现象。在粘弹性聚合物溶液中实验观察到的这种现象是由流体速度和流动弹性之间的强耦合驱动的。为了探索粘弹性流动中这些不稳定性的出现，我们选择了探索，通过直接数值模拟，一个特殊的情况下，称为冯卡门旋流。模拟采用可扩展的非线性Peterlin模型来表示稀聚合物溶液的动力学。值得注意的是，对数构象技术被用来解决的控制方程。这种方法对于克服高Weissenberg数问题是有用的。模拟结果与实验结果基本吻合。将作用在顶板上的扭矩分解为牛顿扭矩和聚合物扭矩两部分，发现聚合物扭矩占主导地位。此外，流动可视化显示，一个环形涡是强烈相关的旋转板上的应力分布。
Viscoelastic fluids have been shown to undergo instabilities even at very low Reynolds numbers, and these instabilities can give rise to a phenomenon called elastic turbulence. This phenomenon, observed experimentally in viscoelastic polymer solutions, is driven by the strong coupling between the fluid velocity and the elasticity of the flow. To explore the emergence of these instabilities in a viscoelastic flow, we have chosen to explore, by means of direct numerical simulations, a particular case called von Karman swirling flow. The simulations employ the finitely extensible nonlinear Peterlin model to represent the dynamics of a dilute polymer solution. Notably, a log-conformation technique is used to solve the governing equations. This method is useful in overcoming the high Weissenberg number problem. The results obtained from the simulations were generally in good agreement with experiments. The torque on the top plate was decomposed into Newtonian and polymeric components, and it was found that the polymeric component was dominant. In addition, flow visualizations revealed that a toroidal vortex was strongly correlated with the distribution of the stresses on the rotating plate.