Numerical simulation about grid fin’s dynamic characteristic by patched mesh

Grid fins are nonconventional aerodynamic control surfaces, which are made of a frame supporting lifting surfaces positioned in the form of a lattice. Grid fins are being investigated by other countries for aerodynamic control of highly maneuverable airlaunched weapons due to their advantage over conventional planar controls at high angles of attack and high Mach numbers. Since their good performance in aerodynamical characteristic, the grid fins have been researched and used in aeronautic and astronautic industry widely. Here, the numerical method based on the patched hybrid mesh is employed to simulate grid fins′ static and dynamic aerodynamic characteristics at different Mach numbers. The validity of this numerical method used here has been proved by the coincidence between the numerical and experimental results. By analyzing the numerical results, while the testing Mach number increasing, the aerodynamic centre of grid fins move upstream at first, then moves downstream. Moreover, it has been noticed during the dynamic numerical test that there are little unsteady retarding phenomena of grid fin′s oscillation in different speed ranges.