Implicit Large-Eddy Simulation of Transition and Turbulence Decay

2019 ◽  
Author(s):  
Fernando F. Grinstein
Keyword(s):  
Large Eddy Simulation ◽  
Isotropic Turbulence ◽  
Navier Stokes ◽  
Homogeneous Isotropic Turbulence ◽  
Eddy Simulation ◽  
Numerical Hydrodynamics ◽  
Geometrical Complexity ◽  
Turbulence Decay ◽  
Large Eddy ◽  
Implicit Large Eddy Simulation

Abstract Accurate predictions with quantifiable uncertainties are essential to many practical turbulent flow applications exhibiting extreme geometrical complexity and broad ranges of length and time scales. Under-resolved computer simulations are typically unavoidable in such applications, and implicit large-eddy simulation (ILES) often becomes the effective strategy. We focus on ILES initialized with well-characterized 2563 homogeneous isotropic turbulence datasets generated with direct numerical simulation (DNS). ILES is based on the LANL xRAGE code, and solutions are examined as function of resolution for 643, 1283, 2563, and 5123 grids. The ILES performance of new directionally-unsplit high-order numerical hydrodynamics algorithms in xRAGE is examined. Compared to the initial 2563 DNS, we find longer inertial subranges and higher turbulence Re for directional-split 2563 & 5123 xRAGE — attributed to having linked DNS (Navier-Stokes based) solutions to nominally inviscid (higher Re) Euler based ILES solutions. Alternatively — for fixed resolution, we find that significantly higher simulated turbulence Re can be achieved with unsplit (vs. split) discretizations.

scholarly journals Implicit large eddy simulation of shock-driven material mixing

2013 ◽  
Vol 371 (2003) ◽  
pp. 20120217 ◽  
Author(s):  
F. F. Grinstein ◽  
A. A. Gowardhan ◽  
J. R. Ristorcelli
Keyword(s):  
Large Eddy Simulation ◽  
Turbulent Mixing ◽  
Initial Conditions ◽  
Spatial Scales ◽  
Late Time ◽  
Eddy Simulation ◽  
Geometrical Complexity ◽  
Planar Shock ◽  
Large Eddy ◽  
Implicit Large Eddy Simulation

Under-resolved computer simulations are typically unavoidable in practical turbulent flow applications exhibiting extreme geometrical complexity and a broad range of length and time scales. An important unsettled issue is whether filtered-out and subgrid spatial scales can significantly alter the evolution of resolved larger scales of motion and practical flow integral measures. Predictability issues in implicit large eddy simulation of under-resolved mixing of material scalars driven by under-resolved velocity fields and initial conditions are discussed in the context of shock-driven turbulent mixing. The particular focus is on effects of resolved spectral content and interfacial morphology of initial conditions on transitional and late-time turbulent mixing in the fundamental planar shock-tube configuration.

scholarly journals Performance of the Finite Element and Finite Volume Methods for Large Eddy Simulation in Homogeneous Isotropic Turbulence

2010 ◽  
Vol 2 (2) ◽  
pp. 237-249 ◽  
Author(s):  
M. A. Uddin ◽  
C. Kato ◽  
N. Oshima ◽  
M. Tanahashi ◽  
T. Miyauchi
Keyword(s):  
Finite Element ◽  
Large Eddy Simulation ◽  
Finite Volume ◽  
Isotropic Turbulence ◽  
Finite Volume Methods ◽  
Homogeneous Isotropic Turbulence ◽  
Smagorinsky Model ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Better Than

Large eddy simulation (LES) in homogeneous isotropic turbulence is performed by using the Finite element method (FEM) and Finite volume vethod (FVM) and the results are compared to show the performance of FEM and FVM numerical solvers. The validation tests are done by using the standard Smagorinsky model (SSM) and dynamic Smagorinsky model (DSM) for subgrid-scale modeling. LES is performed on a uniformly distributed 643 grids and the Reynolds number is low enough that the computational grid is capable of resolving all the turbulence scales. The LES results are compared with those from direct numerical simulation (DNS) which is calculated by a spectral method in order to assess its spectral accuracy. It is shown that the performance of FEM results is better than FVM results in this simulation. It is also shown that DSM performs better than SSM for both FEM and FVM simulations and it gives good agreement with DNS results in terms of both spatial spectra and decay of the turbulence statistics. Visualization of second invariant, Q, in LES data for both FEM and FVM reveals the existence of distinct, coherent, and tube-like vortical structures somewhat similar to those found in instantaneous flow field computed by the DNS. Keywords: Large eddy simulation; Validation; Smagorinsky model; Dynamic Smagorinsky model; Tube-like vortical structure; Homogeneous isotropic turbulence. © 2010 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.DOI: 10.3329/jsr.v2i2.2582              J. Sci. Res. 2 (2), 237-249 (2010) 

The multiscale formulation of large eddy simulation: Decay of homogeneous isotropic turbulence

2001 ◽  
Vol 13 (2) ◽  
pp. 505-512 ◽  
Author(s):  
Thomas J. R. Hughes ◽  
Luca Mazzei ◽  
Assad A. Oberai ◽  
Alan A. Wray
Keyword(s):  
Large Eddy Simulation ◽  
Isotropic Turbulence ◽  
Homogeneous Isotropic Turbulence ◽  
Eddy Simulation ◽  
Large Eddy

Large eddy simulation for aerodynamics: status and perspectives

2009 ◽  
Vol 367 (1899) ◽  
pp. 2849-2860 ◽  
Author(s):  
Pierre Sagaut ◽  
Sébastien Deck
Keyword(s):  
Large Eddy Simulation ◽  
Computational Cost ◽  
Flow Simulation ◽  
Navier Stokes ◽  
Eddy Simulation ◽  
Error Quantification ◽  
Geometrical Complexity ◽  
First Case ◽  
Large Eddy ◽  
First Results

The present paper provides an up-to-date survey of the use of large eddy simulation (LES) and sequels for engineering applications related to aerodynamics. Most recent landmark achievements are presented. Two categories of problem may be distinguished whether the location of separation is triggered by the geometry or not. In the first case, LES can be considered as a mature technique and recent hybrid Reynolds-averaged Navier–Stokes (RANS)–LES methods do not allow for a significant increase in terms of geometrical complexity and/or Reynolds number with respect to classical LES. When attached boundary layers have a significant impact on the global flow dynamics, the use of hybrid RANS–LES remains the principal strategy to reduce computational cost compared to LES. Another striking observation is that the level of validation is most of the time restricted to time-averaged global quantities, a detailed analysis of the flow unsteadiness being missing. Therefore, a clear need for detailed validation in the near future is identified. To this end, new issues, such as uncertainty and error quantification and modelling, will be of major importance. First results dealing with uncertainty modelling in unsteady turbulent flow simulation are presented.

On Flux-Limiting-Based Implicit Large Eddy Simulation

2007 ◽  
Vol 129 (12) ◽  
pp. 1483-1492 ◽  
Author(s):  
Fernando F. Grinstein ◽  
Christer Fureby
Keyword(s):  
Large Eddy Simulation ◽  
Flux Limiter ◽  
Eddy Simulation ◽  
Equation Analysis ◽  
Turbulence Decay ◽  
Large Eddy ◽  
Order Scheme ◽  
Error Terms ◽  
Flux Limiting ◽  
Implicit Large Eddy Simulation

Recent progress in understanding the theoretical basis and effectiveness of implicit large eddy simulation (ILES) is reviewed in both incompressible and compressible flow regimes. We use a modified equation analysis to show that the leading-order truncation error terms introduced by certain hybrid high resolution methods provide implicit subgrid scale (SGS) models similar in form to those of conventional mixed SGS models. Major properties of the implicit SGS model are related to the choice of high-order and low-order scheme components, the choice of a flux limiter, which determines how these schemes are blended locally depending on the flow, and the designed balance of the dissipation and dispersion contributions to the numerical solution. Comparative tests of ILES and classical LES in the Taylor–Green vortex case show robustness in capturing established theoretical findings for transition and turbulence decay.

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