scholarly journals Damping Functions correct over-dissipation of the Smagorinsky Model

2017 ◽  
Vol 40 (16) ◽  
pp. 5933-5945 ◽  
Author(s):  
Ali Pakzad
Keyword(s):  
Smagorinsky Model ◽  
Damping Functions

Robust dynamic adaptation of the Smagorinsky model based on a sub-grid activity sensor

2021 ◽  
Vol 33 (1) ◽  
pp. 015117
Author(s):  
J. Hasslberger ◽  
L. Engelmann ◽  
A. Kempf ◽  
M. Klein
Keyword(s):  
Dynamic Adaptation ◽  
Smagorinsky Model ◽  
Model Based

A hybrid dynamic Smagorinsky model for large eddy simulation

2020 ◽  
Vol 86 ◽  
pp. 108698
Author(s):  
Qingxiang Shui ◽  
Cuie Duan ◽  
Xinyi Wu ◽  
Yunwei Zhang ◽  
Xilian Luo ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Smagorinsky Model ◽  
Eddy Simulation ◽  
Large Eddy

Assessment of turbulence models using DNS data of compressible plane free shear layer flow

2021 ◽  
Vol 931 ◽  
Author(s):  
D. Li ◽  
J. Komperda ◽  
A. Peyvan ◽  
Z. Ghiasi ◽  
F. Mashayek
Keyword(s):  
Shear Layer ◽  
Compressible Flows ◽  
Eddy Viscosity ◽  
Turbulence Models ◽  
Correlation Coefficients ◽  
Free Shear Layer ◽  
Smagorinsky Model ◽  
Reynolds Analogy ◽  
Velocity Fluctuations ◽  
Scale Similarity

The present paper uses the detailed flow data produced by direct numerical simulation (DNS) of a three-dimensional, spatially developing plane free shear layer to assess several commonly used turbulence models in compressible flows. The free shear layer is generated by two parallel streams separated by a splitter plate, with a naturally developing inflow condition. The DNS is conducted using a high-order discontinuous spectral element method (DSEM) for various convective Mach numbers. The DNS results are employed to provide insights into turbulence modelling. The analyses show that with the knowledge of the Reynolds velocity fluctuations and averages, the considered strong Reynolds analogy models can accurately predict temperature fluctuations and Favre velocity averages, while the extended strong Reynolds analogy models can correctly estimate the Favre velocity fluctuations and the Favre shear stress. The pressure–dilatation correlation and dilatational dissipation models overestimate the corresponding DNS results, especially with high compressibility. The pressure–strain correlation models perform excellently for most pressure–strain correlation components, while the compressibility modification model gives poor predictions. The results of an a priori test for subgrid-scale (SGS) models are also reported. The scale similarity and gradient models, which are non-eddy viscosity models, can accurately reproduce SGS stresses in terms of structure and magnitude. The dynamic Smagorinsky model, an eddy viscosity model but based on the scale similarity concept, shows acceptable correlation coefficients between the DNS and modelled SGS stresses. Finally, the Smagorinsky model, a purely dissipative model, yields low correlation coefficients and unacceptable accumulated errors.

scholarly journals Generic Damping Functions for Propagating Importance in Link-Based Ranking

2006 ◽  
Vol 3 (4) ◽  
pp. 445-478 ◽  
Author(s):  
Ricardo Baeza-Yates ◽  
Paolo Boldi ◽  
Carlos Castillo
Keyword(s):  
Damping Functions

scholarly journals Comparative Study of Standard Smagorinsky Model and Dynamic Smagorinsky Model in Large Eddy Simulation of Turbulent Channel Flow

2020 ◽  
Vol 12 (1) ◽  
pp. 39-53
Author(s):  
M. S. I. Mallik ◽  
M. A. Hoque ◽  
M. A. Uddin
Keyword(s):  
Large Eddy Simulation ◽  
Comparative Study ◽  
Channel Flow ◽  
Flow Simulation ◽  
Turbulent Channel Flow ◽  
Smagorinsky Model ◽  
Order Accuracy ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Contour Plots

This paper presents results of comparative study of large eddy simulation (LES) that is applied to a plane turbulent channel flow. The LES is performed by using a finite difference method of second order accuracy in space and a low-storage explicit Runge-Kutta method with third order accuracy in time. In the LES for subgrid-scale (SGS) modelling, Standard Smagorinsky Model (SSM) and Dynamic Smagorinsky Model (DSM) are used. Essential turbulence statistics from the two LES approaches are calculated and compared with those from direct numerical simulation (DNS) data. Comparing the results throughout the calculation domain, it has been found out that SSM performs better than DSM in the turbulent channel flow simulation. Flow structures in the computed flow field by the SSM and DSM are also discussed and compared through the contour plots and iso-surfaces.

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) 

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