Investigation on non-linear characteristic of pitching moment of joined wing configuration aircraft

The joined wing configuration is one of the best configurations for the next transonic aircraft due to the advantage in the drag and lift characteristic, but the pitching moment changes non-linearly with the attack angle increasing in some condition. To solve the problem, the investigations of flow mechanism over jointed wing configuration were conducted by computational flow method and the aerodynamic characteristic for all parts were also analyzed to combined with the flows interaction between the fore-wing and after-wing and the section aerodynamic force distribution in the wing, under the condition of Ma=0.75. The results show that the lack of aerodynamic efficiency of after-wing is caused by the influence of the separation flow over the fore-wing and the pitching moment of the aircraft will increase nonlinearly with the attack angle.