Sonic boom and drag evaluation of supersonic jet concepts

This paper evaluates three different class supersonic airliners (Concorde, Cranfield E-5, and NASA QueSST X-plane) in a multidisciplinary design analysis optimization (MDAO) environment in terms of their sonic boom intensities and aerodynamic performance. The aerodynamic analysis and sonic boom prediction methods are key to this research. The panel method PANAIR is integrated to perform automated aerodynamic analysis. The drag coefficient is corrected by the Harris wave drag formula and form factor method. For sonic boom prediction, the near-field pressure is predicted through the Whitham F-function method. The F-function is decomposed to the F-function due to volume and the F-function due to lift to see their individual effect on sonic boom. The near-field signature propagates in a stratified windy atmosphere using the waveform parameter method. The aerodynamic results are compared with experimental data and the sonic boom prediction results are validated by the NASA PCBoom program. Through the evaluation, we find a direct link between the wave drag and the first derivative of the volume distribution. The sonic boom intensity is influenced by the lift distribution and the volume change rate. The study helps to study the feasibility of low-boom and low-drag supersonic airliners

Comprehensive characterization of airship response to wind and time varying mass

International audienceThis paper addresses the significance of airship time varying inertia properties due to fuel consumption, as well as the effect of external wind, on the dynamic response of an AS500 airship. A previously developed set of nonlinear, 6-DOF airship equations of motion which include the effect of time-varying mass and inertia properties associated with fuel consumption, as well as wind effect, have been implemented with an alternate aerodynamic model that has been validated by flight test. The simulation results obtained are both with and without the time varying mass terms in the equations of motion, in both steady cruise and prevailing wind conditions, and involving the exercise of all control mechanisms on board to include those exciting the airship both longitudinally and laterally