Development of sonic boom prediction code for supersonic transports based on augmented burgers equation

Accurate prediction of sonic-boom level on the ground is still a crucial and challenging task for the design of a low-boom supersonic transport aircraft. In this paper, a method of sonic boom prediction based on augmented Burgers equation is investigated, and a computer code called “bBoom” is developed. Furthermore, influences of the signal interpolating frequency for simulating sonic-boom propagation, thermo-viscous absorption, relaxation processes and atmospheric winds on waveforms are also studied. First, the numerical method of solving augmented Burgers equation considering the thermo-viscous absorption and molecular relaxation processes is presented, especially the methodologies of ray tracing and nonlinear distortion. Second, the prediction method and the code "bBoom" are validated by benchmark test cases including a simple axisymmetric body, JAXA wing-body configuration, NASA C25D configuration, and Lockheed-Martin 1021, which are taken from the 2^nd AIAA Sonic Boom Prediction Workshop. It can be concluded that our code is accurate enough for far-field sonic boom prediction, provided that the near-field pressure signal is accurately inputted. Third, the influences of some key parameters on far-field waveforms and on sonic boom carpet are discussed. Investigation about effects of wind shows that the peak overpressure of N-type waves will be weakened, as an aircraft flies upwind and the direction of wind profile is consistent.