Quantification of Spalart-Allmaras Turbulence Modeling Uncertainties for Hypersonic Flows Utilizing Output-Based Grid Adaptation
Name
Waligura-waligura-masters-AeroAstro-2022-thesis.pdf
Description
Thesis PDF
Size
11.79 MB
Format
Adobe PDF
Checksum (MD5)
217fac7c27c169a62dc2c3b4be6021fd
Author(s)
Waligura, Carter John
Advisor(s)
Harris, Wesley
Grosse, Kyle
Date Issued
May 2022
Publisher
Massachusetts Institute of Technology
Abstract
In this thesis, uncertainty in the Spalart-Allmaras (SA) turbulence model with the compressible Reynolds-averaged Navier-Stokes (RANS) equations is quantified for steady non-reacting hypersonic flows using a coarse-grained uncertainty metric. Output-based adaptation is utilized to guarantee negligible numerical error with complex flow features, such as shock wave-boundary-layer interactions (SBLI). The adapted meshes are generated using MIT Solution Adaptive Numerical Simulator (SANS) software, which is able to adapt high order unstructured meshes using a modified Continuous Galerkin (CG) finite element method (FEM) discretization. The meshes are iteratively adapted by minimizing the error estimate of a given output functional, such as integrated drag or heat flux, over a boundary. The goal of the study is to quantify the expected uncertainty bounds when using the SA model with modifications to the key assumptions of a linear eddy viscosity constitutive relation and incompressible flow. The uncertainty comparison is made between specific areas of hypersonic geometries such as the pre-compression flat plate region and the post-compression shocked-wedge region of a compression corner. Ultimately, this study improves the determination of uncertainty bounds in engineering design involving turbulent flow, provides more insight into exemplary meshing practices for high-speed flow involving SBLI, and highlights where additional work is needed for the development of turbulence models in the hypersonic regime.
MIT Department
Massachusetts Institute of Technology. Department of Aeronautics and Astronautics
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