ABSTRACT Two methods for solid body representation in flow simulations available in the Pencil Code are the immersed boundary method and overset grids. These methods are quite different in terms of computational cost, flexibility and numerical accuracy. We present here an investigation of the use of the different methods with the purpose of assessing their strengths and weaknesses. At present, the overset grid method in the Pencil Code can only be used for representing cylinders in the flow. For this task, it surpasses the immersed boundary method in yielding highly accurate solutions at moderate computational costs. This is partly due to local grid stretching and a body-conformal grid, and partly due to the possibility of working with local time step restrictions on different grids. The immersed boundary method makes up the lack of computational efficiency with flexibility in regard to application to complex geometries, due to a recent extension of the method that allows our implementation of it to represent arbitrarily shaped objects in the flow.

中文翻译：

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使用浸入边界方法和重叠网格处理铅笔代码中的实体对象

摘要 在 Pencil Code 中可用的流动模拟中实体表示的两种方法是浸入边界法和重叠网格。这些方法在计算成本、灵活性和数值精度方面有很大不同。我们在此对不同方法的使用进行了调查，目的是评估它们的优缺点。目前，Pencil Code 中的重叠网格法只能用于表示流动中的圆柱体。对于这项任务，它在以中等计算成本产生高精度解决方案方面超越了浸入边界方法。这部分是由于局部网格拉伸和体共形网格，部分是由于在不同网格上使用局部时间步长限制的可能性。