Large eddy simulation approach

Moreau, M., B. Bedat, and O. Simonin, From Euler-Lagrange to Euler-Euler large eddy simulation approaches for gas-particle turbulent flows, in ASME Fluids Engineering Summer Conference, Houston. 2005, ASME FED. 

Tanaka, M., et al., 2012. Numerical investigation on large scale eddy strucmre in unsteady pipe elbow flow at high Reynolds number conditions with large eddy simulation approach. Journal of Power and Energy Systems 6 (2), 210—228. 

Riber, E., et al.. Towards large eddy simulation of non-homogeneous particle laden turbulent gas flows using Euler-Euler approach, in Eleventh Workshop on Two-Phase Flow Predictions. 2005, Merseburg, Germany. 

The emphasis in this chapter is on the fruitful application of Large Eddy Simulations for reproducing the local and transient flow conditions in which these processes are carried out and on which their performance depends. In addition, examples are given of using Direct Numerical Simulations of flow and transport phenomena in small periodic boxes with the view to find out about relevant details of the local processes. Finally, substantial attention is paid throughout this chapter to the attractiveness and success of exploiting lattice-Boltzmann techniques for the more advanced CFD approaches. 

Van Vliet, E., Derksen, J. J., and Van den Akker, H. E. A., Modelling of Parallel Competitive Reactions in Isotropic Homogeneous Turbulence Using a Filtered Density Function Approach for Large Eddy Simulations . Proc. PVP01 3rd Int. Symp. on Comput. Techn. for Fluid/Thermal/Chemical Systems with Industrial Appl., Atlanta, GE, USA (2001). 

This approach called MILES (monotonically integrated large-eddy simulation) is described in detail elsewhere [22]. This is the same approach used in previous simulations of ramjet combustor flows [17-20]. 

The three main numerical approaches used in turbulence combustion modeling are Reynolds averaged Navier Stokes (RANS) where all turbulent scales are modeled, direct numerical simulations (DNS) where all scales are resolved and large eddy simulations (LES) where larger scales are explicitly computed whereas the effects of smaller ones are modeled ... 

C. D. Pierce and P. Moin. Progress-variable approach for large eddy simulation of non-premixed turbulent combustion. J. Fluid Mech., 504 73-97, 2004. 

If such an approach becomes widespread it will be even more necessary to calibrate and understand its merits and drawbacks by using detailed and accurate computational modelling techniques that have been thoroughly validated, such as Large Eddy Simulation methods (Rodi, 1997 [541]), stochastic simulation methods (Hort et al., 2002 [276] Turfus, 1988 [622]), and time-dependent Reynolds-averaged models. 

This means that larger scale motions can be explicitly resolved and deterministically forecasted. The smaller scale motions, namely turbulence, are not explicitly resolved. Rather, the effects of those sub-grid scales on the larger scales are approximated by turbulence models. These smaller size motions are said to be parameterized by sub-grid scale stochastic (statistical) approximations or modes. The referred experimental data analyzes of the flow in the atmospheric boundary layer determine the basis for the large eddy simulation (LES) approach developed by meteorologists like Deardorff [27] [29] [30]. Large-Eddy Simulation (LES) is thus a relatively new approach to the calculation of turbulent flows. 

Leonard [97] was apparently the first to use the term Large Eddy Simulation. He also introduced the idea of filtering as a formal convolution operation on the velocity field and gave the first general formulation of the method. Since Leonard s approach form the basis for application of LES to chemical reactor modeling, we discuss this approach in further details. 

Ferziger JH, Leshe DC (1979) Large Eddy Simulation A Predictive Approach to Turbulent Flow Computation. American Institute of Aeronautics and Astronautics, Inc., paper A79-45272... 

Three different theoretical approaches have been established describing turbulent flows in general, as outlined in sect 1.3. These methods are the direct numerical simulations (DNS), large eddy simulations (LES), and the Reynolds average Navier-Stokes (RANS) approach. 

H. Pitsch, L. Duchamp de Lageneste, Large-eddy simulation of premixed turbulent combustion using a level-set approach. Proceedings of the Combustion Institute 29 (2) (2002)... 

The flamelet concept for turbulent combustion applies when the reaction is fast compared to the mixture at the molecular level. In this regime, the chemistry of a flame and the turbulence can be treated separately. The flamelet concept approaches the solution of Burke-Schumann for a high Damkohler number and mechanism of one step. The scalar dissipation rate, which appears in the flamelet equations, relates the effects caused by the diffusion and convection. This rate is large at the smallest scales, but its fluctuations are mainly governed by the large scales, which are solved using Large-Eddy Simulation (LES). 

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