scholarly journals Large eddy simulation, turbulent transport and the renormalization group

2016 ◽  
Vol 1 (1) ◽  
pp. 149-180
Author(s):  
James Glimm ◽  
Bradley J. Plohr ◽  
Hyunkyung Lim ◽  
Wenlin Hu ◽  
David H. Sharp
Keyword(s):  
Renormalization Group ◽  
Large Eddy Simulation ◽  
Turbulent Transport ◽  
Eddy Simulation ◽  
Large Eddy

Euler-Euler Large-Eddy Simulation Approach for Non Isothermal Particle-Laden Turbulent Jet

2008 ◽  
Author(s):  
Enrica Masi ◽  
Benoiˆt Be´dat ◽  
Mathieu Moreau ◽  
Olivier Simonin
Keyword(s):  
Large Eddy Simulation ◽  
Particle Temperature ◽  
Turbulent Transport ◽  
A Priori ◽  
Particle Simulation ◽  
Dispersed Phase ◽  
Two Phase Flows ◽  
Two Phase ◽  
Eddy Simulation ◽  
Large Eddy

This paper presents an Euler-Euler Large-Eddy Simulation (LES) approach for the numerical modeling of non isothermal dispersed turbulent two-phase flows. The proposed approach is presented and validated by a priori tests from an Euler-Lagrange database, provided using discrete particle simulation (DPS) of the particle phase coupled with direct numerical simulation (DNS) of the turbulent carrier flow, in a non isothermal particle-laden temporal jet configuration. A statistical approach, the Mesoscopic Eulerian Formalism (MEF) [Fe´vrier et al., J. Fluid Mech., 2005, vol. 533, pp. 1–46], is used to write local and instantaneous Eulerian equations for the dispersed phase and then, by spatial averaging, to derive the LES equations governing the filtered variables. In this work, the MEF approach is extended to scalar variables transported by the particles in order to develop LES for reactive turbulent dispersed two-phase flows with mass and heat turbulent transport. This approach leads to separate the instantaneous particle temperature distribution in a Mesoscopic Eulerian field, shared by all the particles, and a Random Uncorrelated distribution which may be characterized in terms of Eulerian fields of particle moments such as the uncorrelated temperature variance. In this paper, the DPS-DNS numerical database is presented, LES Eulerian equations for the dispersed phase are derived in the frame of the Mesoscopic approach and models for the unresolved subgrid and random uncorrelated terms are proposed and a priori tested using the DPS-DNS database.

Turbulent transport from an arctic lead: A large-eddy simulation

1992 ◽  
Vol 59 (4) ◽  
pp. 315-339 ◽  
Author(s):  
John W. Glendening ◽  
Stephen D. Burk
Keyword(s):  
Large Eddy Simulation ◽  
Turbulent Transport ◽  
Eddy Simulation ◽  
Large Eddy

scholarly journals Connecting the Failure of K Theory inside and above Vegetation Canopies and Ejection–Sweep Cycles by a Large-Eddy Simulation

2017 ◽  
Vol 56 (12) ◽  
pp. 3119-3131 ◽  
Author(s):  
Tirtha Banerjee ◽  
Frederik De Roo ◽  
Matthias Mauder
Keyword(s):  
Large Eddy Simulation ◽  
Time Scale ◽  
Turbulent Flux ◽  
Turbulent Transport ◽  
Sensible Heat Flux ◽  
Quadrant Analysis ◽  
Local Concentration ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Vegetation Canopies

AbstractParameterizations of biosphere–atmosphere interaction processes in climate models and other hydrological applications require characterization of turbulent transport of momentum and scalars between vegetation canopies and the atmosphere, which is often modeled using a turbulent analogy to molecular diffusion processes. Simple flux–gradient approaches (K theory) fail for canopy turbulence, however. One cause is turbulent transport by large coherent eddies at the canopy scale, which can be linked to sweep–ejection events and bear signatures of nonlocal organized eddy motions. The K theory, which parameterizes the turbulent flux or stress proportional to the local concentration or velocity gradient, fails to account for these nonlocal organized motions. The connection to sweep–ejection cycles and the local turbulent flux can be traced back to the turbulence triple moment . In this work, large-eddy simulation is used to investigate the diagnostic connection between the failure of K theory and sweep–ejection motions. Analyzed schemes are quadrant analysis and complete and incomplete cumulant expansion methods. The latter approaches introduce a turbulence time scale in the modeling. Furthermore, it is found that the momentum flux and sensible heat flux need different formulations for the turbulence time scale. Accounting for buoyancy in stratified conditions is also deemed important in addition to accounting for nonlocal events to predict the correct momentum or scalar fluxes.

scholarly journals Exploration of the impact of nearby sources on urban atmospheric inversions using large eddy simulation

Elem Sci Anth ◽  
2017 ◽  
Vol 5 ◽  
Author(s):  
Brian J. Gaudet ◽  
Thomas Lauvaux ◽  
Aijun Deng ◽  
Kenneth J. Davis
Keyword(s):  
Large Eddy Simulation ◽  
Mesoscale Model ◽  
Near Field ◽  
Turbulent Transport ◽  
Analytical Models ◽  
Source Inversion ◽  
Mesoscale Models ◽  
Eddy Simulation ◽  
Large Eddy ◽  
The Impact

The Indianapolis Flux Experiment (INFLUX) aims to quantify and improve the effectiveness of inferring greenhouse gas (GHG) source strengths from downstream concentration measurements in urban environments. Mesoscale models such as the Weather Research and Forecasting (WRF) model can provide realistic depictions of planetary boundary layer (PBL) structure and flow fields at horizontal grid lengths (Δx) down to a few km. Nevertheless, a number of potential sources of error exist in the use of mesoscale models for urban inversions, including accurate representation of the dispersion of GHGs by turbulence close to a point source. Here we evaluate the predictive skill of a 1-km chemistry-adapted WRF (WRF-Chem) simulation of daytime CO2 transport from an Indianapolis power plant for a single INFLUX case (28 September 2013). We compare the simulated plume release on domains at different resolutions, as well as on a domain run in large eddy simulation (LES) mode, enabling us to study the impact of both spatial resolution and parameterization of PBL turbulence on the transport of CO2. Sensitivity tests demonstrate that much of the difference between 1-km mesoscale and 111-m LES plumes, including substantially lower maximum concentrations in the mesoscale simulation, is due to the different horizontal resolutions. However, resolution is insufficient to account for the slower rate of ascent of the LES plume with downwind distance, which results in much higher surface concentrations for the LES plume in the near-field but a near absence of tracer aloft. Physics sensitivity experiments and theoretical analytical models demonstrate that this effect is an inherent problem with the parameterization of turbulent transport in the mesoscale PBL scheme. A simple transformation is proposed that may be applied to mesoscale model concentration footprints to correct for their near-field biases. Implications for longer-term source inversion are discussed.

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