A hybrid analysis of Mach cutoff noise using nonlinear acoustics and finite-difference time-domain method—Comparison with NASA's flight test FaInt–

This paper proposes a 2-D, hybrid analysis method of so-called Mach cutoff noise, which treats boom signature and its disturbance due to collision of the signature with atmospheric turbulence separately. A combination of the augmented Burgers equation analysis and the nonlinear Tricomi equation analysis are applied to the former, while the conventional compact-explicit finite-difference time-domain method is applied to the propagation analysis to the latter. Several numerical experiments using this hybrid method under the same conditions as NASA's flight test FaInt showed that the Perceived Level on the ground is equivalent to the flight test results when the correction from 2-D results to 3-D results is properly made.