Numerical study on drag reduction for sweptback, sweptfront, delta grid fin with blunt and sharp leading

Different grid fin configurations were suggested in previous studies as important ways to overcome the high drag associated to the flow choking in the grid fin cells in different flow regimes. Computational fluid dynamic simulations at transonic speeds and zero attack angles were made to research the aerodynamic charateristics of eight different kinds of grid fins, including the baseline, sweptback, sweptfront and delta models with blunt and sharp leading edges. Individual fin drag coefficient was measured at Mach numbers changing from 0.817 to 1.7, for a total of 72 cases. The results obtained from the numerical simulations indicate that the sweptback, sweptfront and delta grid fins with blunt and sharp leading edges as well as the baseline model with sharp leading edges can reduce the drag force to different extent. And the grid fins with sharp leading edges make a more significant effect on reducing the drag and flow choking than the configurations with blunt leading edges.