论文标题

无拓扑的沉浸式边界方法,用于不可压缩的湍流流:“肮脏” CAD几何形状的空气动力学模拟

Topology-free immersed boundary method for incompressible turbulence flows: An aerodynamic simulation for 'dirty' CAD geometry

论文作者

Onishi, Keiji, Tsubokura, Makoto

论文摘要

为了设计一种方法来解决处理“肮脏”且高度复杂的几何形状的问题,将无拓扑方法与沉浸边界方法结合使用,以在较高的雷诺数下用于粘性和不可压缩的流。该方法同时采用幽灵细胞技术并分布强迫技术来施加边界条件。轴预发的插值方案用于避免在流体和固体识别过程中搜索故障。该方法产生无拓扑的浸入边界,特别适合高度复杂的几何形状的流动模拟。对于这些情况生成计算网格时,通常会出现困难。此方法允许处理肮脏的数据,而无需进行任何预备处理工作以简化或清理几何形状。该方法还适用于本研究中采用的相干结构湍流模型。与二阶中央差异方案结合使用的验证案例导致了更固定分辨率的一阶准确度,尽管更粗的分辨率保留了二阶精度。对于分布式内存平台,此方法完全平行。在这项研究中,通过模拟虚张声势周围的流动,经过平板和过去的肮脏球,检查了该方法的准确性和忠诚度。将这些模拟与实验数据和其他既定结果进行了比较。最后,实际应用的模拟结果证明了该方法对高度复杂,非规范的三维流进行建模的能力。基于几何特征的准确分类的对策提供了强大而合理的解决方案。

To design a method to solve the issues of handling 'dirty' and highly complex geometries, the topology-free method combined with the immersed boundary method is presented for viscous and incompressible flows at a high Reynolds number. The method simultaneously employs a ghost-cell technique and distributed forcing technique to impose the boundary conditions. An axis-projected interpolation scheme is used to avoid searching failures during fluid and solid identification. This method yields a topology-free immersed boundary, which particularly suits flow simulations of highly complex geometries. Difficulties generally arise when generating the calculation grid for these scenarios. This method allows dirty data to be handled without any preparatory treatment work to simplify or clean-up the geometry. This method is also applicable to the coherent structural turbulence model employed in this study. The verification cases, used in conjunction with the second-order central-difference scheme, resulted in first-order accuracy at finer resolution, although the coarser resolution retained second-order accuracy. This method is fully parallelized for distributed memory platforms. In this study, the accuracy and fidelity of this method were examined by simulating the flow around the bluff body, past a flat plate, and past dirty spheres. These simulations were compared with experimental data and other established results. Finally, results from the simulation of practical applications demonstrate the ability of the method to model highly complex, non-canonical three-dimensional flows. The countermeasure based on the accurate classification of geometric features has provided a robust and reasonable solution.

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