Jet interactions with body flaps are important problems that cannot be ignored in the design of reusable spacecraft. In this paper, nonlinear characteristics of jet interactions have been demonstrated in transonic wind tunnel experiments, and flow mechanisms are analyzed. Then, according to typical subsonic, transonic, and supersonic conditions, numerical simulations of wind tunnel and free flight are performed using the species frozen model. Airflow in the cabin of the model is analyzed as one of the factors that may cause differences between experiments and numerical simulations.Symmetrical reusable vehicle, main engine jet interaction, wind tunnel experiment, numerical simulation