Modelling and Validation of Covariance Transport Equations for Large-Eddy-Simulation of Ternary, Turbulent Mixing

2010 ◽  
pp. 27-34
Author(s):  
Frank Victor Fischer ◽  
Wolfgang Polifke
Keyword(s):  
Large Eddy Simulation ◽  
Turbulent Mixing ◽  
Transport Equations ◽  
Eddy Simulation ◽  
Large Eddy

Subgrid scale modeling considerations for large eddy simulation of supercritical turbulent mixing and combustion

2021 ◽  
Vol 33 (7) ◽  
pp. 075112
Author(s):  
Umesh Unnikrishnan ◽  
Hongfa Huo ◽  
Xingjian Wang ◽  
Vigor Yang
Keyword(s):  
Large Eddy Simulation ◽  
Turbulent Mixing ◽  
Subgrid Scale ◽  
Eddy Simulation ◽  
Scale Modeling ◽  
Large Eddy ◽  
Subgrid Scale Modeling

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 Stably Stratified Flows: A Model with No Ri(cr)*

2008 ◽  
Vol 65 (7) ◽  
pp. 2437-2447 ◽  
Author(s):  
V. M. Canuto ◽  
Y. Cheng ◽  
A. M. Howard ◽  
I. N. Esau
Keyword(s):  
Numerical Simulation ◽  
Large Eddy Simulation ◽  
Direct Numerical Simulation ◽  
Turbulent Mixing ◽  
Stratified Flows ◽  
The Other ◽  
Large Set ◽  
Eddy Simulation ◽  
Stably Stratified Flows ◽  
Large Eddy

Abstract A large set of laboratory, direct numerical simulation (DNS), and large eddy simulation (LES) data indicates that in stably stratified flows turbulent mixing exists up to Ri ∼ O(100), meaning that there is practically no Ri(cr). On the other hand, traditional local second-order closure (SOC) models entail a critical Ri(cr) ∼ O(1) above which turbulence ceases to exist and are therefore unable to explain the above data. The authors suggest how to modify the recent SOC model of Cheng et al. to reproduce the above data for arbitrary Ri.

Analysis and Optimization of Turbulent Mixing With Large Eddy Simulation

2006 ◽  
Author(s):  
Ying Huai ◽  
Amsini Sadiki
Keyword(s):  
Large Eddy Simulation ◽  
Turbulent Mixing ◽  
Optimization Procedure ◽  
Impinging Jet ◽  
Computational Domain ◽  
Original Design ◽  
Mixing Processes ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Practical Engineering

In this work, Large Eddy Simulation (LES) has been carried out to analyze the turbulent mixing processes in an impinging jet configuration. To characterize and quantify turbulent mixing processes, in terms of scalar structures and degree of mixing, three parameters have been basically introduced. They are “mixedness parameter”, which represents the probability of mixed fluids in computational domain, the Spatial Mixing Deficiency (SMD) and the Temporal Mixing Deficiency (TMD) parameters for characterizing the mixing at different scalar scale degrees. With help of these parameters, a general mixing optimization procedure has then been suggested and achieved in an impinging jet configuration. An optimal jet angle was estimated and the overall mixing degree with this jet angle reached around six times more than the original design. It turns out that the proposed idea and methodology can be helpful for practical engineering design processes.

Homogeneity of the Subgrid-Scale Turbulent Mixing in Large-Eddy Simulation of Shallow Convection

2013 ◽  
Vol 70 (9) ◽  
pp. 2751-2767 ◽  
Author(s):  
Dorota Jarecka ◽  
Wojciech W. Grabowski ◽  
Hugh Morrison ◽  
Hanna Pawlowska
Keyword(s):  
Large Eddy Simulation ◽  
Turbulent Mixing ◽  
Droplet Radius ◽  
Subgrid Scale ◽  
Shallow Convection ◽  
Eddy Simulation ◽  
Droplet Concentration ◽  
Large Eddy ◽  
Double Moment ◽  
The Mean

Abstract This paper presents an approach to locally predict homogeneity of the subgrid-scale turbulent mixing in large-eddy simulation of shallow clouds applying double-moment warm-rain microphysics. The homogeneity of subgrid-scale mixing refers to the partitioning of the cloud water evaporation due to parameterized entrainment between changes of the mean droplet radius and changes of the mean droplet concentration. Homogeneous and extremely inhomogeneous mixing represent two limits of possible scenarios, where the droplet concentration and the mean droplet radius remains unchanged during the microphysical adjustment, respectively. To predict the subgrid-scale mixing scenario, the double-moment microphysics scheme is merged with the approach to delay droplet evaporation resulting from entrainment. Details of the new scheme and its application in the Barbados Oceanographic and Meteorological Experiment (BOMEX) shallow convection case are discussed. The simulated homogeneity of mixing varies significantly inside small convective clouds, from close to homogeneous to close to extremely inhomogeneous. The mean mixing characteristics become more homogeneous with height, reflecting increases of the mean droplet size and the mean turbulence intensity, both favoring homogeneous mixing. Model results are consistent with microphysical effects of entrainment and mixing deduced from field observations. Mixing close to homogeneous is predicted in volumes with the highest liquid water content (LWC) and strongest updraft at a given height, whereas mixing in strongly diluted volumes is typically close to extremely inhomogeneous. The simulated homogeneity of mixing has a small impact on mean microphysical characteristics. This result agrees with the previous study applying prescribed mixing scenarios and can be explained by the high humidity of the clear air involved in the subgrid-scale mixing.

Large-Eddy Simulation study of turbulent mixing in a T-junction

2010 ◽  
Vol 240 (9) ◽  
pp. 2116-2122 ◽  
Author(s):  
A.K. Kuczaj ◽  
E.M.J. Komen ◽  
M.S. Loginov
Keyword(s):  
Large Eddy Simulation ◽  
Simulation Study ◽  
Turbulent Mixing ◽  
Eddy Simulation ◽  
Large Eddy
Sign in / Sign up

Export Citation Format

Share Document