A novel adaptive control dynamic-grids generation method based on two-dimensional body fitted grids is developed, which offers a solution to the application of high-precision structured grids in the complicated moving and deforming boundary flow field problem. There have been some dynamic-grids methods proposed by researchers, such as the spring-smoothing method based on unstructured grids, the diffusion-smoothing method based on structured grids, and overset grids method. The ability of methods based on unstructured grids to achieve high grid quality in near-wall region is relatively limited. The deterioration of grid quality could hardly be avoided with the solution processing for the diffusion-smoothing method. To reduce the interpolation error between the background grid and the embedded grid when using overset grid method, the grid quantity needs to be increased considerably.

In these methods, advantages of structured grids in the accuracy and rate of generation, and the applicability of turbulence model, have not been made full use of. The adaptive control method manages to generate updated high-precision body fitted structured grids in each time step according to the movement and deformation of flow field boundaries. Therefore some frequent problems occurred in previous dynamic-grids methods, including grids intersection and quality deterioration, are solved efficiently. Especially in the boundary layer region, the quality of near-wall structured grids can be guaranteed, which is vital to match up with advanced turbulence models. To validate the advantages of adaptive control method, a numerical simulation of fish-like undulation flow field is performed using different dynamic-grids methods. The grids quality, the computational cost and the simulation accuracy of these methods are compared to demonstrate the effectiveness of the adaptive control method. Researches of flow field with moving and deforming boundaries are supposed to benefit from this new dynamic-grids method.