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Flows passing a wide-body aircraft at cruising, drag divergence or diving status are transonic. When the aircraft model is tested in a transonic wind tunnel, strong shock waves may be induced due to the tunnel wall and the model, and incur complex interference as a strong nonlinear coupling phenomenon. In order to investigate the wall interference to the standard model of a wide-body aircraft mounted in the FL-26 wind tunnel, a numerical simulation method based on a porous wall model is developed. Based on this wall model method, the coupling effect of wall interference at Mach numbers ranging from 0.8 to 0.92 is studied. Comparing with the wall pressure information method, results with the porous wall model indicate positive effect of the porous wall flow on the lift coefficient of wide-body aircraft, as well as more modification to drag coefficient.

Computational fluid dynamics and rigid body dynamics models are solved in a loosely coupled way to simulate a missile launched from an aircraft by rail, the motions consist of three phases, which correspond to two or multi- hanger phase, single hanger phase and free motion phase. In order to simulate the motion of missiles subjected to single hanger constraint, the constrained dynamics equations are derivated from six degree of freedom motion equations, the model is verified by simulating free rotation of rigid body (Euler gyro) and procession of rotational rigid body( Lagrange gyro), which shows good agreement with the theoretical solutions. After that, the launching process of a missile from an aircraft is numerically simulated, in which constrained and non-constrained rigid-body dynamics models are switched corresponding to hanger's position. By numerical simulation, trajectories and attitudes profile of the missile are obtained. The results show that the missile is impacted by lateral wash flows at moderate angles of attack, resulting in large lateral force and yawing moment, causing the missile to roll rapidly and produce missile-frame interference further. In the phase of single hanger constraint, the missile tends to pitch due to normal aerodynamic force, gravity, normal overload and soon, which may lead to interference with rail launcher on harsh conditions. [ABSTRACT FROM AUTHOR]