Effect of longitudinal lift distribution on sonic boom of a canard-wing-stabilator-body configuration

Abstract

After the last flight of the Concorde in 2003, sonic boom has been one of the obstacles to the return of a supersonic transport aircraft to service. To reduce the sonic boom intensity to an acceptable level, it is of great significance to study the effect of lift distribution on far-field sonic boom, since lift is one of the most important contributors to an intense sonic boom. Existing studies on the longitudinal lift distribution used low-fidelity methods, such as Whitham theory, and in turn, only preliminary conclusions were obtained, such as that extending the lift distribution can reduce sonic boom. This paper uses a newly developed high-fidelity prediction method to quantitatively study the effect of longitudinal lift distribution on the sonic boom of a Canard-Wing-Stabilator-Body (CWSB) configuration. This high-fidelity prediction method combines near-field CFD simulation with far-field propagation by solving the augmented Burgers equation. A multipole analysis method is employed for the extraction of near-field waveform in order to reduce computational cost. Seven configurations with the same total lift but different distributions are studied, and the quantitative relationship between the longitudinal lift distribution and far-field sonic boom intensity is investigated. It is observed that a small lift generated by the stabilator can prevent aft-stabilator and aft-fuselage shocks from merging, while the balanced lift generated by the canard and wing can effectively keep the corresponding shocks further apart, which is beneficial for reducing both the on-track and off-track sonic boom. In turn, the acoustic level perceived at the ground can be reduced by 5.9 PLdB on-track and 5.4 PLdB off-track, on average.