CFD analysis of roll damping derivatives for missile with grid fins at supersonic speeds

Roll damping derivative is an important aerodynamic coefficient which determines the dynamic stability of missile. Computational fluid dynamic simulations were used to predict roll damping derivative of missile with planar and grid fins at supersonic speeds based on steady flow. Compared with planar fins, roll damping derivative of grid fins has complex variation, the trend curve has two turning points as the angle of attack increases, which are due to the influence of separated flow to grid fins and stall of the fins separately; the derivative of planar fins get smaller as Mach number increases, while the curve of grid fins changes twice and gets a maximum point at Ma=3.5.