Analysis of Convergence Behavior for the Overset Mesh Based Numerical Wave Tank in openfoam
Analysis of Convergence Behavior for the Overset Mesh Based Numerical Wave Tank in openfoam
复制标题
开放泡沫中基于重叠网格的数值波浪池收敛行为分析
DOI：
10.1115/1.4063265
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发表时间：
2024
期刊：
影响因子：
--
通讯作者：
Chen H
中科院分区：
文献类型：
--
作者：
Chen H
本文提出了一种解决方案的验证和验证研究基于重叠网格的数值波浪水槽在openfoam，它考虑了自由表面水动力学流动模型，刚体运动模型和重叠网格之间的耦合。刚体运动解算器和自由表面流动解算器之间的耦合以分离的方式实现。利用数值波浪水槽模拟了驳船横摇运动的自由衰减，并选择阻尼系数作为目标量进行解的验证。采用基于最小二乘的解决方案验证程序，其中四种类型的误差估计量之一在最小二乘意义下拟合数据。结构和非结构网格进行了测试，并仔细研究其对收敛阶，数值不确定性和误差的影响。数值试验表明，数值波浪水槽对结构网格下的浮体问题具有很好的收敛性，即在空间上接近二阶，在时间上接近一阶。然而，当贴体网格转换为非结构网格时，网格收敛性降低到一阶。非结构化网格对时域收敛阶次的影响不大，但由于数据的分散性，会导致较大的不确定性。
This paper presents a solution verification and validation study for an overset mesh based numerical wave tank in openfoam, which considers the coupling between a free-surface hydrodynamic flow model, a rigid body motion model, and an overset mesh. The coupling between the rigid body motion solver and the free-surface flow solver was achieved in a segregated manner. Free decay of roll motion of a barge was modeled using the numerical wave tank, and the damping coefficient was selected as the target quantity for solution verification. The least-square based solution verification procedure was adopted, where one of the four types of error estimators was fit to the data in the least-square sense. Both structured and unstructured mesh were tested, and their effects on the convergence order, numerical uncertainty, and error were carefully investigated. From the numerical tests, it is found that the numerical wave tank exhibits a very good convergence property for the floating body problems with structured mesh, ie, nearly second order in space and first order in time. However, when switching the body-fitted mesh to unstructured mesh, the grid convergence is reduced to first order. Unstructured mesh does not significantly affect the convergence order in time domain, but results in a larger uncertainty due to data scattering.