Falling balls in a viscous fluid with contact: Comparing numerical simulations with experimental data
Falling balls in a viscous fluid with contact: Comparing numerical simulations with experimental data
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DOI：
10.1063/5.0037971
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发表时间：
2020-11
期刊：
影响因子：
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通讯作者：
Henry von Wahl;T. Richter;S. Frei;T. Hagemeier
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文献类型：
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作者：
Henry von Wahl;T. Richter;S. Frei;T. Hagemeier
我们评估了一些不同的有限元方法的流体-结构（接触）相互作用问题对物理实验的数据。为此，我们采用Hagemeier的实验数据[Mendeley Data，doi：10.17632/mf27c92nc3.1]。这包括单个颗粒通过高粘性流体下落并从底部流体罐壁反弹的轨迹。由此产生的流动处于蠕动和湍流之间的过渡状态。这种类型的配置是特别具有挑战性的数值方法，由于大的变化的流体域和壁与颗粒之间的接触。在数值模拟中，我们考虑刚体和线弹性模型的下降颗粒。在第一种情况下，我们得到的结果与成熟的任意拉格朗日欧拉（ALE）的方法和移动域CutFEM方法与一个简单的和常见的接触避免的方法。对于完整的流体-结构相互作用（FSI）问题的接触，我们使用一个完整的欧拉方法结合使用Nitsche的方法统一的FSI接触处理。为了更高的计算效率，我们使用的几何对称性的实验设置重新制定的FSI系统到两个空间维度。最后，我们展示了完整的三维ALE计算，以研究粒子初始状态中的小扰动的影响，以研究实验中观察到的完全垂直下降的偏差。这些方法在开源有限元库中实现，结果可以免费获得，以帮助再现性。
We evaluate a number of different finite element approaches for fluid-structure (contact) interaction problems against data from physical experiments. For this we take the data from experiments by Hagemeier [Mendeley Data, doi: 10.17632/mf27c92nc3.1]. This consists of trajectories of single particles falling through a highly viscous fluid and rebounding off the bottom fluid tank wall. The resulting flow is in the transitional regime between creeping and turbulent flows. This type of configuration is particularly challenging for numerical methods due to the large change of the fluid domain and the contact between the wall and particle. In the numerical simulations we consider both rigid body and linear elasticity models for the falling particles. In the first case, we compare results obtained with the well established Arbitrary Lagrangian Eulerian (ALE) approach and a moving domain CutFEM method together with a simple and common approach for contact avoidance. For the full fluid-structure interaction (FSI) problem with contact, we use a fully Eulerian approach in combination with a unified FSI-contact treatment using Nitsche's method. For higher computational efficiency we use the geometrical symmetry of the experimental set up to reformulate the FSI system into two spatial dimensions. Finally, we show full three dimensional ALE computations to study the effects of small perturbations in the initial state of the particle to investigate deviations from a perfectly vertical fall observed in the experiment. The methods are implemented in open-source finite element libraries and the results are made freely available to aide reproducibility.