Wave Drag Characteristics of a Low-Drag Supersonic Formation Flying Concept

摘要

In this study, the drag characteristics of a concept to achieve low drag by formation flying of supersonic transports has been investigated. The drag characteristics have been checked for different arrangements of the formation. From these results, it can be concluded that the supersonic formation flying concept showed up to 17.9% increase in L/D and therefore deserves further research as a means to reduce the wave drag of a fleet of supersonic aircraft. The best L/D values were achieved when the following aircraft interacts with the expansion fan of the leading aircraft. To organize the data taking into account the physics of the drag reduction mechanism, a new coordinate system, which is made up of parameters that indicate the degree of interaction with the shock and expansion fans, has been introduced. This coordinate system has been proven to be very effective in categorizing the patterns of wave interference. In this coordinate system, the interaction with shock and expansion fans is dominated by x_μ, and the effect of diffusion of the shock and expansion fans is expressed by r. This coordinate system also succeeded in showing the sensitivity of wave drag to the relative position of the aircraft. Results indicated that different formations have different degrees of sensitivity, and θ could be adjusted to trade off performance for dynamic characteristics.