Aerodynamics Analysis On Effects Of Downwash Induced By Canard On Roll Control Of The Rocket With Canard Configuration

When canard was used to roll control in Canard configuration, the asymmetric downwash flow produced by canard would induce the tail to generate additional rolling moment, which is contrary to the direction of the canard’s rolling moment. To improve the roll control ability of the canard, a study was conducted to research the influence on roll control characteristics for the canard-tail-spacing and the install position of the canard. Analyzed the flow field characteristics and aerodynamic characteristics,explained the mechanism of the reverse rolling moment of the tail induced by the downwash flow of the canard and discussed some new configuration to improve the performance of canard’s roll control.First of all, the Wind Tunnel Test and CFD of a rocket with canard configuration was conducted to confirm the reliability of CFD through the comparison of their aerodynamic characteristics.In order to study the influence of canard-tail spacing on rolling characteristics, a different canard-tail spacing model was designed and CFD was used to simulate the two models. The calculation results and the analysis of flow field showed that the canard-tail-spacing has great influence on the rolling moment, and with the decrease of the canard-tail-spacing, the reverse rolling moment of the tail which is induced by the canards becomes larger and the roll control capability of the canard was weakened. Then a study was conducted to research the influence on roll control characteristics for the different install positions of the canard. Based on the original model, a new model which installs the canard on the cylindrical section was designed. The comparison of CFD simulation results and the analysis of flow field showed that the install position of the canard has great influence on the rolling moment coefficient of the canard with transonic speed, the coefficient when the canard was installed on the cylindrical section was far bigger than on the conic section. Generally speaking, The postposition of the canard was unprofitable for roll control with subsonic speed but favorable with transonic speed, and there is little difference with supersonic speed.Finally, a hypothesis was putted forward on the base of previous researches and discussed some configuration, which install a spoiler on the back of canard’s position, to seek the influence of the spoiler on the rolling moment of the tail induced by downwash.