Novel Cartesian Grid-Stitching Algorithm Suitable for Dynamic-Boundary Euler Equation Computations

The aerodynamic characteristics of flowfields involving dynamic boundaries are complicated, imposing rigorous demands on grid generation and solution accuracy for numerical computations. Existing grid methodologies, such as overlapping grids and dynamic unstructured grids, struggle to ensure computational efficiency and solution accuracy simultaneously. Consequently, this paper presents a novel Cartesian grid-stitching algorithm designed to tackle the complexities associated with dynamic boundary problems. Firstly, a boundary normal projection approach is introduced for grid stitching, constructing a Cartesian-like grid capable of automated reconfiguration. The body-fitted portion dynamically selects nodes from the Cartesian grid for reconstruction, ensuring no grid distortion and eliminating the need for frequent deletion or addition of grid cells. Therefore, it demonstrates high adaptability to complex configurations and readily accommodates aerodynamic challenges involving moving boundaries with large-scale motion. Secondly, at the grid-stitching interfaces, the finite difference method for an unstructured grid is employed for spatial variable discretization, eliminating interpolation errors typically introduced. It enables interpolation-free information interaction between grids, achieving consistent discretization accuracy across the entire computational domain. Furthermore, three sets of numerical tests are conducted, with simulating results showing good agreement with those in the literature. This algorithm has proven effective in accurately capturing flow features involving shockwave interactions.