The Oriented-Eddy Collision Model

The physical and mathematical foundations of the Oriented-Eddy Collision turbulence model are provided through a discussion of the Reynolds averaged Navier-Stokes (RANS) equations, probability density functions (PDF), PDF collision models, Reynolds stress transport models (RSTM), and two-point corre...

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Main Author: Martell, Michael Bernard, Jr.
Format: Others
Published: ScholarWorks@UMass Amherst 2012
Subjects:
Online Access:https://scholarworks.umass.edu/open_access_dissertations/583
https://scholarworks.umass.edu/cgi/viewcontent.cgi?article=1585&context=open_access_dissertations
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spelling ndltd-UMASS-oai-scholarworks.umass.edu-open_access_dissertations-15852020-12-02T14:39:49Z The Oriented-Eddy Collision Model Martell, Michael Bernard, Jr. The physical and mathematical foundations of the Oriented-Eddy Collision turbulence model are provided through a discussion of the Reynolds averaged Navier-Stokes (RANS) equations, probability density functions (PDF), PDF collision models, Reynolds stress transport models (RSTM), and two-point correlations. Behavior of the Oriented-Eddy Collision turbulence model near solid boundaries is examined in depth. The Oriented-Eddy Collision turbulence model treats turbulence in a novel way: the average behavior of a turbulent flow can be modeled as a collection of interacting fluid particles, or eddies, which have inherent orientation. The model is cast in the form of a collection of Reynolds stress transport models. Underlying this approach is a unique PDF collision model that departs from more common PDF methods as it includes orientation information along with the usual position and velocity information. This adds important physics and differentiates it from other PDF collision treatments that return RANS-type models. To operate in physical space, the model is cast as a unique decomposition to the two-point velocity correlation transport equation. The Oriented-Eddy Collision turbulence model accurately captures fast pressure-strain in rapid distortion, which is a major shortcoming of nearly all Reynolds stress transport models. The Oriented-Eddy Collision turbulence model contains no special provisions to satisfy realizability, and maintains frame and coordinate invariance. Models to account for turbulent dissipation, diffusion, and system rotation are presented with canonical benchmark flows for validation. Inhomogeneous, anisotropic cases are also considered. Model to capture non-local pressure effects near solid boundaries are proposed in the form of turbulent eddy reorientation schemes with associated Reynolds stress treatments. These schemes aim to capture the asymptotic approach of the Reynolds stress components and basic turbulent, wall-bounded flows are investigated as a means of validation. Boundary conditions for solid and shear-free surfaces are discussed and several alternatives to the standard viscous diffusion model proposed. 2012-05-01T07:00:00Z text application/pdf https://scholarworks.umass.edu/open_access_dissertations/583 https://scholarworks.umass.edu/cgi/viewcontent.cgi?article=1585&context=open_access_dissertations Open Access Dissertations ScholarWorks@UMass Amherst Fluid Structure Turbulence Mechanical Engineering
collection NDLTD
format Others
sources NDLTD
topic Fluid
Structure
Turbulence
Mechanical Engineering
spellingShingle Fluid
Structure
Turbulence
Mechanical Engineering
Martell, Michael Bernard, Jr.
The Oriented-Eddy Collision Model
description The physical and mathematical foundations of the Oriented-Eddy Collision turbulence model are provided through a discussion of the Reynolds averaged Navier-Stokes (RANS) equations, probability density functions (PDF), PDF collision models, Reynolds stress transport models (RSTM), and two-point correlations. Behavior of the Oriented-Eddy Collision turbulence model near solid boundaries is examined in depth. The Oriented-Eddy Collision turbulence model treats turbulence in a novel way: the average behavior of a turbulent flow can be modeled as a collection of interacting fluid particles, or eddies, which have inherent orientation. The model is cast in the form of a collection of Reynolds stress transport models. Underlying this approach is a unique PDF collision model that departs from more common PDF methods as it includes orientation information along with the usual position and velocity information. This adds important physics and differentiates it from other PDF collision treatments that return RANS-type models. To operate in physical space, the model is cast as a unique decomposition to the two-point velocity correlation transport equation. The Oriented-Eddy Collision turbulence model accurately captures fast pressure-strain in rapid distortion, which is a major shortcoming of nearly all Reynolds stress transport models. The Oriented-Eddy Collision turbulence model contains no special provisions to satisfy realizability, and maintains frame and coordinate invariance. Models to account for turbulent dissipation, diffusion, and system rotation are presented with canonical benchmark flows for validation. Inhomogeneous, anisotropic cases are also considered. Model to capture non-local pressure effects near solid boundaries are proposed in the form of turbulent eddy reorientation schemes with associated Reynolds stress treatments. These schemes aim to capture the asymptotic approach of the Reynolds stress components and basic turbulent, wall-bounded flows are investigated as a means of validation. Boundary conditions for solid and shear-free surfaces are discussed and several alternatives to the standard viscous diffusion model proposed.
author Martell, Michael Bernard, Jr.
author_facet Martell, Michael Bernard, Jr.
author_sort Martell, Michael Bernard, Jr.
title The Oriented-Eddy Collision Model
title_short The Oriented-Eddy Collision Model
title_full The Oriented-Eddy Collision Model
title_fullStr The Oriented-Eddy Collision Model
title_full_unstemmed The Oriented-Eddy Collision Model
title_sort oriented-eddy collision model
publisher ScholarWorks@UMass Amherst
publishDate 2012
url https://scholarworks.umass.edu/open_access_dissertations/583
https://scholarworks.umass.edu/cgi/viewcontent.cgi?article=1585&context=open_access_dissertations
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