The Effect of Turbulence Model Uncertainty on Scramjet Isolator Flow Field Analysis


The goal of this work was to perform an uncertainty and sensitivity analysis of commonly used turbulence models in Reynolds-averaged Navier-Stokes flow solvers due to epistemic uncertainty arising from ambiguities in the model coefficients. The uncertainty analysis was applied to simulations of a model scramjet isolator. The Menter-BSL, Menter-SST, Spalart-Allmaras, and Wilcox-2006 k − ω turbulence models were examined and simulations were carried out using the VULCAN flow solver, developed and maintained at the NASA Langley Research Center. Non-intrusive polynomial chaos theory was used for efficient uncertainty propagation and Sobol indices were employed to establish relative sensitivities of the flow solution to closure coefficients. The results obtained were compared to experimental data as well as to previous work focusing on different flow problems. Sets of closure coefficients that contribute most to solution uncertainty for each turbulence model were identified, which warrant further investigation as more knowledge about the effects of these coefficients is expected to reduce the uncertainty in the numerical design of scramjet isolators.

Meeting Name

22nd AIAA International Space Planes and Hypersonics Systems and Technologies Conference (2018: Sep. 17-19, Orlando, FL)


Mechanical and Aerospace Engineering

Research Center/Lab(s)

Center for High Performance Computing Research

Keywords and Phrases

Chaos theory; Flow simulation; NASA; Navier Stokes equations; Polynomials; Ramjet engines; Reynolds equation; Sensitivity analysis; Turbulence models, Epistemic uncertainties; Model uncertainties; NASA Langley Research Center; Polynomial chaos theory; Relative sensitivity; Reynolds-averaged Navier Stokes flow solver; Uncertainty and sensitivity analysis; Uncertainty propagation, Uncertainty analysis

International Standard Book Number (ISBN)


Document Type

Article - Conference proceedings

Document Version


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© 2018 American Institute of Aeronautics and Astronautics (AIAA), All rights reserved.

Publication Date

01 Sep 2018