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You searched for +publisher:"University of Colorado" +contributor:("Yuri Bazilevs"). Showing records 1 – 2 of 2 total matches.

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University of Colorado

1. Coley, Christopher Joel. Residual-Based Large Eddy Simulation of Turbulent Flows Using Divergence-Conforming Discretizations.

Degree: PhD, 2017, University of Colorado

In this dissertation, a class of methods which combines divergence-conforming discretizations with residual-based subgrid modeling for large eddy simulation of turbulent flows is introduced. These methods fall within two frameworks: residual-based variational multiscale methods and residual-based eddy viscosities. These methods utilize variationally-consistent formulations for the fine-scale velocities in order to construct subgrid-scale models based on the coarse-scale residual. The result is an LES methodology that responds naturally to spatially- and temporally-varying turbulence. Numerical results demonstrate that these new methods demonstrate proper behavior for homogeneous turbulence and outperform classical LES models for transitional flows and wall-bounded turbulent flows. Furthermore, the resulting formulations contain no ``tunable'' parameters, and thus extend generally across various classes of flow. [object Object] Additionally, a differential variational multiscale method in which the unresolved fine-scales are approximated element-wise using a discontinuous Galerkin method is presented and examined. Stability and convergence results for the methodology as applied to the scalar transport problem are established, and it is proven that the method exhibits optimal convergence rates in the SUPG norm and is robust with respect to the Péclet number if the discontinuous subscale approximation space is sufficiently rich. The method is applied to isogeometric NURBS discretizations of steady and unsteady transport problems, and the corresponding numerical results demonstrate that the method is stable and accurate in the advective limit even when low-order discontinuous subscale approximations are employed. Based on these promising results, a class of differential subgrid vortex models for large eddy simulation of turbulent flows is proposed. Finally, the underlying discretization utilized by the simulations here offers the opportunity to develop efficient new geometric multigrid linear solvers. In this regard, a geometric multigrid methodology for the solution of matrix systems associated with isogeometric compatible discretizations of the generalized Stokes and Oseen problems is presented. The methodology provably yields a pointwise divergence-free velocity field independent of the number of pre-smoothing steps, post-smoothing steps, grid levels, or cycles in a V-cycle implementation. The methodology relies upon Scwharz-style smoothers in conjunction with specially defined overlapping subdomains that respect the underlying topological structure of the generalized Stokes and Oseen problems. Numerical results in both two- and three-dimensions demonstrate the robustness of the methodology through the invariance of convergence rates with respect to grid resolution and flow parameters for the generalized Stokes problem as well as the generalized Oseen problem, provided it is not advection-dominated. Advisors/Committee Members: John A. Evans, Kenneth Jansen, Carlos Felippa, Peter Hamlington, Yuri Bazilevs.

Subjects/Keywords: Divergence-conforming; Large eddy simulation; Residual-based large eddy simulation; Structure-preserving; Turbulence modeling; Variational multiscale method; Aerospace Engineering

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Coley, C. J. (2017). Residual-Based Large Eddy Simulation of Turbulent Flows Using Divergence-Conforming Discretizations. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/asen_gradetds/172

Chicago Manual of Style (16th Edition):

Coley, Christopher Joel. “Residual-Based Large Eddy Simulation of Turbulent Flows Using Divergence-Conforming Discretizations.” 2017. Doctoral Dissertation, University of Colorado. Accessed October 16, 2019. https://scholar.colorado.edu/asen_gradetds/172.

MLA Handbook (7th Edition):

Coley, Christopher Joel. “Residual-Based Large Eddy Simulation of Turbulent Flows Using Divergence-Conforming Discretizations.” 2017. Web. 16 Oct 2019.

Vancouver:

Coley CJ. Residual-Based Large Eddy Simulation of Turbulent Flows Using Divergence-Conforming Discretizations. [Internet] [Doctoral dissertation]. University of Colorado; 2017. [cited 2019 Oct 16]. Available from: https://scholar.colorado.edu/asen_gradetds/172.

Council of Science Editors:

Coley CJ. Residual-Based Large Eddy Simulation of Turbulent Flows Using Divergence-Conforming Discretizations. [Doctoral Dissertation]. University of Colorado; 2017. Available from: https://scholar.colorado.edu/asen_gradetds/172


University of Colorado

2. Coley, Christopher Joel. Residual-Based Large Eddy Simulation of Turbulent Flows Using Divergence-Conforming Discretizations.

Degree: PhD, 2017, University of Colorado

In this dissertation, a class of methods which combines divergence-conforming discretizations with residual-based subgrid modeling for large eddy simulation of turbulent flows is introduced. These methods fall within two frameworks: residual-based variational multiscale methods and residual-based eddy viscosities. These methods utilize variationally-consistent formulations for the fine-scale velocities in order to construct subgrid-scale models based on the coarse-scale residual. The result is an LES methodology that responds naturally to spatially- and temporally-varying turbulence. Numerical results demonstrate that these new methods demonstrate proper behavior for homogeneous turbulence and outperform classical LES models for transitional flows and wall-bounded turbulent flows. Furthermore, the resulting formulations contain no "tunable'' parameters, and thus extend generally across various classes of flow. Additionally, a differential variational multiscale method in which the unresolved fine-scales are approximated element-wise using a discontinuous Galerkin method is presented and examined. Stability and convergence results for the methodology as applied to the scalar transport problem are established, and it is proven that the method exhibits optimal convergence rates in the SUPG norm and is robust with respect to the Péclet number if the discontinuous subscale approximation space is sufficiently rich. The method is applied to isogeometric NURBS discretizations of steady and unsteady transport problems, and the corresponding numerical results demonstrate that the method is stable and accurate in the advective limit even when low-order discontinuous subscale approximations are employed. Based on these promising results, a class of differential subgrid vortex models for large eddy simulation of turbulent flows is proposed. Finally, the underlying discretization utilized by the simulations here offers the opportunity to develop efficient new geometric multigrid linear solvers. In this regard, a geometric multigrid methodology for the solution of matrix systems associated with isogeometric compatible discretizations of the generalized Stokes and Oseen problems is presented. The methodology provably yields a pointwise divergence-free velocity field independent of the number of pre-smoothing steps, post-smoothing steps, grid levels, or cycles in a V-cycle implementation. The methodology relies upon Scwharz-style smoothers in conjunction with specially defined overlapping subdomains that respect the underlying topological structure of the generalized Stokes and Oseen problems. Numerical results in both two- and three-dimensions demonstrate the robustness of the methodology through the invariance of convergence rates with respect to grid resolution and flow parameters for the generalized Stokes problem as well as the generalized Oseen problem, provided it is not advection-dominated. Advisors/Committee Members: John A. Evans, Kenneth Jansen, Carlos Felippa, Peter Hamlington, Yuri Bazilevs.

Subjects/Keywords: divergence-conforming; large eddy simulation; residual-based large eddy simulation; structure-preserving; turbulence modeling; variational multiscale method; Aerospace Engineering; Applied Mathematics

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Coley, C. J. (2017). Residual-Based Large Eddy Simulation of Turbulent Flows Using Divergence-Conforming Discretizations. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/asen_gradetds/220

Chicago Manual of Style (16th Edition):

Coley, Christopher Joel. “Residual-Based Large Eddy Simulation of Turbulent Flows Using Divergence-Conforming Discretizations.” 2017. Doctoral Dissertation, University of Colorado. Accessed October 16, 2019. https://scholar.colorado.edu/asen_gradetds/220.

MLA Handbook (7th Edition):

Coley, Christopher Joel. “Residual-Based Large Eddy Simulation of Turbulent Flows Using Divergence-Conforming Discretizations.” 2017. Web. 16 Oct 2019.

Vancouver:

Coley CJ. Residual-Based Large Eddy Simulation of Turbulent Flows Using Divergence-Conforming Discretizations. [Internet] [Doctoral dissertation]. University of Colorado; 2017. [cited 2019 Oct 16]. Available from: https://scholar.colorado.edu/asen_gradetds/220.

Council of Science Editors:

Coley CJ. Residual-Based Large Eddy Simulation of Turbulent Flows Using Divergence-Conforming Discretizations. [Doctoral Dissertation]. University of Colorado; 2017. Available from: https://scholar.colorado.edu/asen_gradetds/220

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