Research, development and application of technique of unstructured rotational dynamic overset grids

Starting from our earlier work in Ref. 9, this paper does further research to develop unstructured rotational dynamic overset grids for solving the 2-D/3-D unsteady flow problems which contain rotational dynamic boundaries. We decompose the computational domain into the two sub-domains: the rotational one containing rotational boundaries and the stationary one containing the remainder flow field including stationary boundaries. The artificial boundaries and the restrictive boundaries are jointly used as the restrictive conditions for generating the whole computational grid, and then we establish the overset grids according to the artificial boundaries. We use the spring analysis theory to treat the deformation of body boundaries, solve the unsteady N-S equations in the rotational sub-domain and the stationary sub-domain respectively and accomplish their data coupling in the overlapping domain. We use three examples to numerically and respectively simulate the steady flow around the NACA0012 airfoil, the 3-D rotor-fuselage interaction unsteady flow field and the unsteady flow around a flutter excitation system; the simulation results, given in Figs. 6 and 8, and their analysis show preliminarily that: (1) the results have good agreement with the experimental data; (2) our technique is efficient and robust for the prediction of complicated unsteady flows which contain rotational dynamic boundaries.