Aerodynamic design of supersonic experimental airplane

In the first stage of the NAL's experiment for supersonic transport (NEXST-1: Next generation Supersonic Transport-l) project, the aerodynamic design has focused on the of drag at a supersonic cruising speed with a clean wing-body configuration by using Computational Fluid Dynamics (CFD). In the course of design process, four aerodynamic concepts have been applied; (1) arrow-type planform design (2) warped wing (3) area-ruled body (4) a Natural Laminar Flow (NLF) wing. (1) and (2) are effective for the reduction of drag due to lift while (3) is effective the reduction of wave drag due to volume. They are the concepts based on the linear theory. The concept (4) is devised for the reduction of the friction drag. The application of the NLF concept to the SST (SuperSonic Transport) configuration has no previous instance and an original trial. For the realization of the NLF wing at supersonic cruising speed, we first designed a pressure distribution on the wing and then applied an inverse design method based on the supersonic small perturbation equation. After less than 10 design cycles, we obtained satisfactory design result which display a good agreement with target pressure. The transition position was evaluated by an incompressible boundary layer stability code (SALLY code) and compressible boundary layer stability code (LSTAB code), the latter of which was developed in NAL. The evaluation revealed that the turbulence transition characteristics are good.
JAXA Special Publication
宇宙航空研究開発機構特別資料