| According to structural features of the active UAV inlet, a study of bilateral type S-shaped inlet with large offset and short diffuser is presented in this paper. This approach includes choosing the inlet center line and area regularity, design of the beveled lip, and so on. Some CFD studies were carried out in this paper, and the results not only coincided with experiment results, but also provided many details of flow field. As the performance of the inlet was deteriorated at large angle of yaw, outside flow field was studied in the article and primary reasons were that vortex of the fuselage influenced free stream. At last, a model of the inlet was made and a test was conducted in the wind tunnel. In the experiment, the performance of the inlet had been obtained, such as the effects on performance of free stream Mach number, angle of attack and yaw. Wind tunnel tests show that:1) In a state of zero angle of attack and yaw, total pressure recovery of the S-shaped inlet is changed little with Mach of free stream increasing. The distortion of inlet is less than 0.14 and the law is that it makes smaller firstly and then becomes larger, achieves minimum at Mach number 0.70, but range of the change is very small.2) Total pressure recovery of the S-shaped inlet is reduced slowlly with angel of attack increasing at Ma 0.63,β= 0°. DC60 is changed little. It shows that the design of the beveled lip is reasonable.3) At Ma 0.63,α= 0°, the performances of inlet with positive and negative yaw are different. Total pressure recovery of the inlet is increased firstly and then reduced with angel of yaw increasing, and its value at negative yaw is higher. DC60 is changed little at negative yaw and small positive yaw , but it increases fastly at larger positive yaw.4) The inlet has a good performance in the test. Total pressure recovery is always larger than 0.986 and the distortion is also under 0.28 when Mach number ranges from 0.50 to 0.70,αranges from ? 2°to 8°andβranges from ? 2°to 2°.5) The inlet located at lee side of fuselage with large yaw angle is great influenced by the boundary layer and vortex of the fuselage, so the distortion of inlet is deteriorating than before, which needs control methods of flow field to reduce swirl, but the total pressure recovery is quite high. |
