Robust Cut-Cell Cartesian Mesh Generation Method for Moving Boundaries

The Cartesian mesh is often used in computational fluid dynamics due to its ease of generation and ability to handle complex geometries. However, additional operations are usually required to generate body-fitted Cartesian cells. In this study, a robust Cartesian mesh generation method based on the cut-cell method is proposed for flow problems with moving boundaries. The key steps involved in this method are the procedures for cutting boundary cells and the construction of cut-cells. Nevertheless, robustness issues often occur in these two steps, especially when moving boundaries are present. To address these issues, a robust intersection point computation method is put forward during the cutting process, which adopts topological information to avoid numerical errors. Besides, a loop-matching algorithm is introduced for the construction of the cut-surfaces and side-cut-surfaces. For flow problems with moving boundaries, a common operation is to identify the cells that require updating. Therefore, a method is introduced to identify these cells with the introduction of boundary markers efficiently. Several numerical examples are presented to demonstrate the effectiveness of the proposed method in handling problems with moving boundaries.