Abstract
Hypersonic flight-vehicles create shock and expansion waves that propagate through the atmosphere and are observed on the ground as sonic booms. We present a methodology to predict the near-field aerodynamic pressure and sonic boom signature using approximately 1% of the computational cost relative to fully-nonlinear computational fluid dynamics and state-ofthe-art sonic boom propagation solvers. Relative differences in predictions between the present method and the state-of-the-art are approximately 8%. We find that unique physics must be accounted for in the hypersonic regime, which includes viscous, non-equilibrium, and real gas effects. The method is based on the fully-parabolized Navier-Stokes equations, which are solved via marching in the propagation direction to the aerodynamic near-field. The near-field aerodynamic pressure is propagated through the atmosphere to the ground via the waveform parameter method, and is validated with NASA PCBoom and data from the NASA Sonic Boom Workshops. To illustrate the approach, three bodies are analyzed: the Sears-Haack geometry, the HIFiRE-5 hypersonic test vehicle, and a power-law waverider. Global Mach numbers range from 4.0 through 15.0. We find that the viscous stress tensor is essential for accurate hypersonic prediction. For example, viscous effects increase near-field and sonic boom overpressure by 15.7% and 8.49%, respectively for the Sears-Haack geometry. Finally, we show that the divergence of viscous versus inviscid near-field predictions are due to the hypersonic boundary layer.
Published Version
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