An Improved Control Method of Variable Net Structure with Feature Constraint Parameters

A robust control method is important but also challenging in variable net structure with moving boundary, especially when the deformation is large. In this paper, we present an improved control method with feature constraint parameters to improve the robustness of variable net structure. In details, the size constraint parameters can avoid the collapse of the elements in the net structure, the angle constraint parameters reduce the distortion of poor elements, and the shape constraint parameters correct the elements to obtain a better net structure. Two kinds of net quality parameters are used to evaluate the robustness of variable net structure. Several cases are tested and discussed, including the pitching of a two-dimensional airfoil, and the stretching of a cubic box. The results show that the improved control method can create better-deformed net structure than two classical control methods, even avoids the "negative volume" element when the deformation is large.