High-Fidelity Prediction of Launch Vehicle Lift-off Acoustic Environment

Launch vehicles experience extreme acoustic loads during liftoff driven by the interaction of rocket plumes and plume-generated acoustic waves with ground structures. Currently employed predictive capabilities are too dissipative to accurately resolve the propagation of waves throughout the launch environment. Higher fidelity non-dissipative analysis tools are critically needed to design mitigation measures (such as water deluge) and launch pad geometry for current and future NASA and commercial launch vehicles. This project will develop and deliver breakthrough technologies to drastically improve acoustic loads predictions. An innovative hybrid CFD and Computational Aeroacoustics (CFD/CAA) method will be developed where established RANS/LES modeling will be used for predicting the acoustic generation physics, and a high-order accurate unstructured discontinuous Galerkin (DG) method will be employed to propagate acoustic waves across large distances using ideally suited high-order accurate schemes. This new paradigm enables: (1) Improved fidelity over linear methods; (2) Greatly reduced numerical dissipation and dispersion; and (3) Improved acoustics modeling for attenuation, diffraction, and reflection from complex geometry. A proof-of-concept was developed and successfully demonstrated during Phase I for benchmark applications as well as SLS prototype model launch environments. Phase II will deliver production CFD/CAA predictive capabilities with 4th-order spatial and temporal accuracy for near lossless acoustic propagation throughout the launch environment, which will provide NASA engineers with more than a two-fold increase in the range of resolvable frequencies over current methods.