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Improving Fidelity of Launch Vehicle Liftoff Acoustic SimulationsLaunch vehicles experience high acoustic loads during ignition and liftoff affected by the interaction of rocket plume generated acoustic waves with launch pad structures. Application of highly parallelized Computational Fluid Dynamics (CFD) analysis tools optimized for application on the NAS computer systems such as the Loci/CHEM program now enable simulation of time-accurate, turbulent, multi-species plume formation and interaction with launch pad geometry and capture the generation of acoustic noise at the source regions in the plume shear layers and impingement regions. These CFD solvers are robust in capturing the acoustic fluctuations, but they are too dissipative to accurately resolve the propagation of the acoustic waves throughout the launch environment domain along the vehicle. A hybrid Computational Fluid Dynamics and Computational Aero-Acoustics (CFD/CAA) modeling framework has been developed to improve such liftoff acoustic environment predictions. The framework combines the existing highly-scalable NASA production CFD code, Loci/CHEM, with a high-order accurate discontinuous Galerkin (DG) solver, Loci/THRUST, developed in the same computational framework. Loci/THRUST employs a low dissipation, high-order, unstructured DG method to accurately propagate acoustic waves away from the source regions across large distances. The DG solver is currently capable of solving up to 4th order solutions for non-linear, conservative acoustic field propagation. Higher order boundary conditions are implemented to accurately model the reflection and refraction of acoustic waves on launch pad components. The DG solver accepts generalized unstructured meshes, enabling efficient application of common mesh generation tools for CHEM and THRUST simulations. The DG solution is coupled with the CFD solution at interface boundaries placed near the CFD acoustic source regions. Both simulations are executed simultaneously with coordinated boundary condition data exchange.
Document ID
20160014579
Acquisition Source
Marshall Space Flight Center
Document Type
Presentation
Authors
Liever, Peter
(Jacobs Engineering and Science Services and Skills Augmentation Group (ESSSA) Huntsville, AL, United States)
West, Jeff
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Date Acquired
December 9, 2016
Publication Date
November 13, 2016
Subject Category
Launch Vehicles And Launch Operations
Acoustics
Report/Patent Number
M16-5568
Meeting Information
Meeting: SC16: International Conference for High Performance Computing, Networking, Storage and Analysis
Location: Salt Lake City, UT
Country: United States
Start Date: November 13, 2016
End Date: November 18, 2016
Sponsors: IEEE Computer Society
Funding Number(s)
CONTRACT_GRANT: NNM12AA41C
Distribution Limits
Public
Copyright
Public Use Permitted.
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