Experimental Study on Interference Aerodynamic Characteristics of Aft Ejection Separation of Rudder-Controlled Missiles

Aft ejection separation of rudder-controlled missiles has advantages in thermal protection, shape preservation, drag reduction, multiple delivery, recovery and so on, and is expected to become a preferred approach for missile releasing from high speed vehicle. As a result, a new type of multi-body separation problem is faced: Aft Supersonic Ejection Separation (ASES) problem. The ASES problem is a coupled problem consisting of supersonic base wake flow with rear cavity and multi-body separation, characterized by complex flow structure and significant unsteady, nonlinear and non-symmetric aerodynamic effects. For the supersonic aft ejection separation problem, the Schlieren, grid method and Captive Trajectory System (CTS) wind tunnel test technologies were used to study the structure of interference wake flow and aerodynamics. It was found that there are three typical zones of interference according to the flow structure and change of rudder effectiveness: low-speed-subsonic without shock zone, high-subsonic-transonic weak shock zone, supersonic shock zone. It shows that the aerodynamics of the missile are severely affected by the wake flow interference, and there is a significant nonlinear characteristic between the separation distance and aerodynamics. The maximum reduction of rudder effectiveness of the missile is nearly 40%, but no reverse rudder effectiveness has occurred. As separation distance gradually increases, the rudder effectiveness gradually recovers. The effects of angle of attack, sideslip angle, Mach number, and control law on separation are also studied.