Spectrum analysis of aerodynamic interference from canard's shedding vortex on a dual-spin projectile using improved delayed detached eddy simulation

The dual-spin projectile, a two-dimensional correction projectile, achieves ballistic correction at a reduced cost by controlling the fore-body canards. While canards generate control forces, their shedding vortex also create significant aerodynamic interference on the projectile, resulting in nonlinear unsteady aerodynamic loads with complex frequency information that can lead to “catastrophic yaw.” To accurately analyze the spectrum of aerodynamic interference of canards, high-resolution computational fluid dynamics simulations were conducted for a dual-spin projectile with fixed canards, employing an improved delayed detached eddy simulation. A novel Cp mode extraction method for rotating wall was developed to investigate the impact of the canard's shedding vortex on the pressure coefficient (Cp) distribution of the projectile. This method reveals the potential relationship between Cp and aerodynamic forces on rotating walls in Fourier space, enabling the isolation of the Cp mode associated with canard-induced pitching/yawing moment at the target frequency. The results indicate that the shedding vortex pair at canard's root forms local low-pressure zones on the projectile body, inducing periodic normal and lateral forces on the projectile body. This aerodynamic force accounts for approximately 17% of the aerodynamic force generated by the canard. As the angle of attack increases, the shedding vortex pair experiences periodic changes as the canard rotates, leading to periodic interference loads with frequencies ranging from 1 to 4 times the rotation speed of the canard.