Title:
Wall-models for large eddy simulation based on a generic additive-filter formulation

dc.contributor.advisor Menon, Suresh
dc.contributor.author Sánchez Rocha, Martín en_US
dc.contributor.committeeMember Cvitanović, Predrag
dc.contributor.committeeMember Sankar, Lakshmi N.
dc.contributor.committeeMember Smith, Marilyn J.
dc.contributor.committeeMember Yeung, P. K.
dc.contributor.department Aerospace Engineering en_US
dc.date.accessioned 2009-06-08T18:43:12Z
dc.date.available 2009-06-08T18:43:12Z
dc.date.issued 2008-12-19 en_US
dc.description.abstract In this work, the mathematical implications of merging two different turbulence modeling approaches are addressed by deriving the exact hybrid RANS/LES Navier-Stokes equations. These equations are derived by introducing an additive-filter, which linearly combines the RANS and LES operators with a blending function. The equations derived predict additional hybrid terms, which represent the interactions between RANS and LES formulations. Theoretically, the prediction of the hybrid terms demonstrates that the hybridization of the two approaches cannot be accomplished only by the turbulence model equations, as it is claimed in current hybrid RANS/LES models. The importance of the exact hybrid RANS/LES equations is demonstrated by conducting numerical calculations on a turbulent flat-plate boundary layer. Results indicate that the hybrid terms help to maintain an equilibrated model transition when the hybrid formulation switches from RANS to LES. Results also indicate, that when the hybrid terms are not included, the accuracy of the calculations strongly relies on the blending function implemented in the additive-filter. On the other hand, if the exact equations are resolved, results are only weakly affected by the characteristics of the blending function. Unfortunately, for practical applications the hybrid terms cannot be exactly computed. Consequently, a reconstruction procedure is proposed to approximate these terms. Results show, that the model proposed is able to mimic the exact hybrid terms, enhancing the accuracy of current hybrid RANS/LES approaches. In a second effort, the Two Level Simulation (TLS) approach is proposed as a near-wall model for LES. Here, TLS is first extended to compressible flows by deriving the small-scale equations required by the model. The full compressible TLS formulation and the hybrid TLS/LES approach is validated simulating the flow over a flat-plate turbulent boundary layer. Overall, results are found in reasonable agreement with experimental data and LES calculations. en_US
dc.description.degree Ph.D. en_US
dc.identifier.uri http://hdl.handle.net/1853/28086
dc.publisher Georgia Institute of Technology en_US
dc.subject Near-wall models for LES en_US
dc.subject Turbulence modeling en_US
dc.subject Derivation of governing equations en_US
dc.subject Compressible TLS formulation en_US
dc.subject Hybrid RANS/LES governing equations en_US
dc.subject.lcsh Eddies
dc.subject.lcsh Computer simulation
dc.subject.lcsh Turbulence
dc.subject.lcsh Mathematical models
dc.title Wall-models for large eddy simulation based on a generic additive-filter formulation en_US
dc.type Text
dc.type.genre Dissertation
dspace.entity.type Publication
local.contributor.advisor Menon, Suresh
local.contributor.corporatename College of Engineering
local.contributor.corporatename Daniel Guggenheim School of Aerospace Engineering
local.relation.ispartofseries Doctor of Philosophy with a Major in Aerospace Engineering
relation.isAdvisorOfPublication 67d13e49-1e1d-4ce9-ac87-8f1a49266904
relation.isOrgUnitOfPublication 7c022d60-21d5-497c-b552-95e489a06569
relation.isOrgUnitOfPublication a348b767-ea7e-4789-af1f-1f1d5925fb65
relation.isSeriesOfPublication f6a932db-1cde-43b5-bcab-bf573da55ed6
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