supersonic transport, sonic boom reduction, low sonic boom design, sonic boom pressure waveform, aerodynamic design, least square method, computational fluid dynamics, optimization method, airframe shape, linear theory
その他のタイトル(英)
An aerodynamic design method for generating low sonic-boom pressure signatures
National Aerospace Laboratory Advanced Technology Aircraft Project Center
National Aerospace Laboratory Fluid Science Research Center
National Aerospace Laboratory Computational Science Division
University of Tokyo Graduate School of Engineering
University of Tokyo Graduate School of Engineering
A study was conducted of an aerodynamic design for the sonic-boom reduction of supersonic transport. Sonic-boom is one of the most important environmental problems for supersonic transport and methods for reduction of sonic-boom intensity have been published. These previous low sonic-boom design methods utilize the F-function method which is based on a linear theory. In comparison a new low sonic-boom design method is proposed in this study in order to deal with the nonlinear effects of the strong shocks near the aircraft and the three-dimensional effects of the aircraft configuration unable to be taken into account in the F-function method. This new low sonic-boom design method combines a three-dimensional Euler CFD (Computational Fluid Dynamics) code with a least-square optimization technique. The aircraft fuselage geometry is modified by this method in order to minimize the pressure differences between a pressure signature calculated by the CFD and a target low sonic-boom pressure signature produced in the near-field below the aircraft. This target near-field pressure signature is determined from the target low sonic-boom ground signature by utilizing the waveform parameter method. It will be demonstrated here that the sonic-boom intensity of the low sonic-boom aircraft configuration designed by the F-function method is reduced by this new low sonic-boom design method.