Effect of Wing Pressure Distribution on Sonic-Boom Intensity of Supersonic Transport Aircrafts

Low sonic-boom and low drag characteristics are both important for the next-generation supersonic transport aircraft. The natural-laminar-flow (NLF) wing design technology is able to remarkably reduce the friction drag and thus improve the cruising efficiency of an aircraft. It is achieved by aerodynamic shape design on the wing to obtain the required pressure distribution which can suppress the growth of unstable waves in the boundary layer. However, the change of the wing geometry and pressure distribution could influence the sonic-boom intensity of the aircraft. In order to compromise low sonic-boom and low drag characteristics, the mechanism of how the pressure distribution influences the sonic-boom intensity is of great interest to researchers. The objective of this article is to investigate the effect of wing pressure distribution on sonic-boom intensity and reveal the relationship between low sonic-boom design and natural-laminar-flow wing design on supersonic transport aircrafts. First, the CST method is used to disturb airfoils of a typical supersonic transport wing-body configuration to obtain a set of configurations with different wing pressure distributions. Second, the flow fields of these configurations are calculated using RANS equation, and the undertrack near-field overpressure is extracted from the flow field of each configuration. The equivalent area due to volume and equivalent area due to lift are also analyzed. Finally, the undertrack near-field overpressure is propagated to the ground using augmented Burgers equation. Results show that the variation of wing pressure distributions by disturbing airfoils has more significant influence on the equivalent area due to lift, which indicates that we can compromise low sonic-boom and low drag characteristics by restricting equivalent area due to lift during NLF wing design on supersonic transport aircrafts.