低声爆超声速客机声爆预测及不确定度量化分析

Accurate prediction of sonic booms is one of the key bottlenecks restricting the breakthrough of supersonic aircraft technology. To obtain a more reliable near- and far-field signals of a sonic boom, it is necessary to consider the influence of the uncertainty of incoming flow parameters that fluctuate continuously. Moreover, key factors affecting the accurate prediction of sonic booms need to be identified to provide a valuable guideline for practical applications. In this paper, the sonic boom characteristics of the supersonic aircraft C608 provided by the 3rd sonic boom prediction workshop (SBPW-3) are analyzed based on the near-field signal simulation based on Computational Fluid Dynamics and the far-field signal prediction method based on the augmented Burgers equation. Firstly, the near-field over-pressure value is calculated using an unstructured hybrid grid with 50.21 million cells for half of the model, and the temporal and spatial grid convergence of far-field ground waveform is studied. Secondly, the complex near-field flow characteristics and ground waveform characteristics in the reference state are analyzed. Compared with the public data of aircraft C608, the accuracy of the method and the in-house-development program has been effectively verified. In addition, the effects of different physical models and atmospheric relative humidity on the ground waveform are also investigated. On this basis, the uncertainty quantification and sensitivity analysis of different incoming flow parameters (Mach number, angle of attack, and unit Reynolds number) are carried out by using the non-intrusive polynomial chaos (NIPC) and Sobol index method. The results show that, for a given uncertainty of input variables, the overpressure values at the peak and trough of ground waveform differ significantly. In contrast, the influence of unit Reynolds number is significantly smaller than those of Mach number and angle of attack.