An accurate conservative interpolation method for the mixed gridbased on the intersection of grid cells
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摘要: 基于网格切割思想,发展了二维/三维混合网格条件下的单元相交算法,可精确计算任意两个多边形/多面体的交集。在此基础上,实现了基于单元相交(CIB/DC)的精确守恒插值算法。二维和三维验证算例表明,该方法能够保证插值过程中计算域内物理量的严格守恒,且具有比常规二阶插值更高的精度。Abstract: A method is presented for conservatively transferring cell-centered physical quantities from one mesh to another with second-order accuracy, which is well-suited for finite-volume methods that rely on cell-centered variables. The proposed methodology implements the cell-intersection algorithm of 2D/3D mixed grid based on the local supermesh idea, and is able to accurately calculate the intersection of any two polygons or polyhedrons, thus providing a basis for accurate conservative interpolation. The accuracy and the efficacy of the new method are demonstrated with multiple 2D and 3D numerical experiments. The test results show that this method ensures strict conservation of physical quantities in the interpolation process, and achieves a higher accuracy than that achieved by conventional second-order interpolation methods.
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Key words:
- fluid mechanics /
- conservative interpolation /
- cell-intersection /
- mixed grid /
- local supermesh
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表 1 计算网格参数
Table 1. Parameters of the computational grid
序号 结构网格 非结构网格 节点数 单元数 1 33×33 695 1 260 2 65×65 2 593 4 928 3 129×129 10 044 19 574 4 257×257 39 687 78 348 表 2 不同算例的守恒误差
Table 2. Conservation errors indifferent numerical cases
序号 二阶插值 守恒型二阶插值 1 3.724×10-3 0 2 -1.447×10-3 0 3 -3.985×10-4 1×10-14 4 5.636×10-5 -2×10-14 表 3 计算网格参数
Table 3. Parameters of the computational grid
序号 网格1 网格2 dx 节点数 单元数 节点数 单元数 1 914 4 033 676 2 711 0.067 2 2 222 10 632 1 424 6 075 0.050 3 6 527 32 913 3 733 16 681 0.035 4 26 099 138 542 12 600 59 347 0.022 -
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