An efficient grid assembling method in unsteady dynamic motion simulation using overset grid

The overset grid method may be a competitive choice of structured grid to discretize the progressively complicated aerodynamic shapes. Grid assembling process is a unique process for the overset grid method, which should be done repeatedly followed by any occurrence of grid motion in unsteady dynamic motion simulation. In this work, a simplified grid assembling method for the unsteady dynamic overset grid method is devised and validated. The grid motion information, generally including the position or the speed of the solid body, could be viewed as an additional information. The difference of the grid position indicates the change of the relative position of the grid points. The relative position of a grid point is very critical in the corresponding grid assembling process. The traditional grid assembling method usually omits the additional grid motion information. The proposed method utilizes the difference value of the grid position and the specially designed grid system to simplify the traditional grid assembling method. Three test cases including a 2D airfoil with different motion types and a 3D commercial airplane with pitching motion are implemented to demonstrate the high efficiency of the proposed method while the accuracy is kept. According to the results, the proposed method saves more than 85% of the computational time spent on the grid assembling process. This method is potentially a better candidate for the unsteady motion simulation using overset grid.