AERODYNAMIC DESIGN OF A SUPERSONIC TRANSPORT CONFIGURATION CONSIDERING AVERAGE LOUDNESS IN THE WHOLE BOOM CARPET

Sonic booms remain the primary barrier restraining the development of supersonic transport (SST). The existing low-boom design methods primarily focus on mitigating under-track sonic boom intensity, which may increase the loudness at off-track locations in the sonic boom carpet. To solve this problem, a low-boom design method which can reduce the sonic boom across the whole boom carpet is proposed. First, the sonic boom prediction method is introduced and validated by the JWB configuration of SBPW2. Then, an average loudness metric termed full-carpet boom loudness (FBL) is formulated, which can consider the contribution of loudness and impact area at different off-track angles. By integrating the FBL and surrogate-based optimization, a full-carpet low-boom design optimization method is proposed. Finally, the proposed method is applied to the aerodynamic design of a low-boom SST configuration. After design, the sonic booms at all off-track angles are mitigated. The FBL is reduced from 80.79 PLdB to 79.84 PLdB and maximum loudness reduction in the carpet is 1.96 PLdB. The shock wave pattern of designed configuration is softer and the tail shocks are weakened. Additionally, the cruise lift-to-drag ratio is also improved by 2.3%. The design configuration maintains favorable low-boom characteristics at off-design conditions of ±0.1 Mach number and ±0.1° angle of attack off the design point. This research can provide insight for the low-boom design of SST configurations.