Title

Algorithms and Models for Turbulence Not at Statistical Equilibrium

Abstract

Standard eddy viscosity models, while robust, cannot represent backscatter and have severe difficulties with complex turbulence not at statistical equilibrium. This report gives a new derivation of eddy viscosity models from an equation for the evolution of variance in a turbulent flow. The new derivation also shows how to correct eddy viscosity models. The report proves the corrected models preserve important features of the true Reynolds stresses. It gives algorithms for their discretization including a minimally invasive modular step to adapt an eddy viscosity code to the extended models. A numerical test is given with standard and over diffusive eddy viscosity models. The correction (scaled by 10-8) does exhibit intermittent backscatter.

Meeting Name

Advances in Scientific Computing and Applied Mathematics, ASCAM-2015 (2015: Oct. 9–12, Las Vegas, NV)

Department(s)

Mathematics and Statistics

Comments

Second author was partially supported by NSF grant DMS 1216465 and AFOSR grant FA9550-12-1-0191 .

Keywords and Phrases

Algorithms; Backscattering; Reynolds number; Turbulence; Discretizations; Eddy viscosity; Eddy viscosity model; Important features; Minimally invasive; Numerical tests; Reynolds stress; Statistical equilibrium; Viscosity; Backscatter; Complex turbulence

International Standard Serial Number (ISSN)

0898-1221

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2016 Elsevier, All rights reserved.

Publication Date

01 Jun 2016

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