To achieve good characteristics of an axisymmetric supersonic mixed-compression inlet at different angles of attack

a feasible and available variable-geometry technique was proposed and demonstrated by changing the shock system structure of the forebody with a pivoting first cone.The 3-D flow field and performance characteristics of the variable-geometry inlet at Mach 3 and 4 were investigated numerically over a wide range of angles of attack

and the results were compared with those of the conventional fixed-geometry inlet.The results indicate:(1) By rotating the first cone

the mass flow coefficient of the inlet is improved and the low-energy flow accumulation at the leeward side is relieved effectively at high angle of attack.(2) There exists an optimum value of the angle of rotation

enabling the inlet to reach the highest performance at given high angle of attack.(3) With the increase of angle of attack

the optimum angle of rotation increases

and the thrust augmentation also increases to 7.7% at Mach 3 and angle of attack of 14°.