Large Eddy Simulation (LES)

What is a Large-eddy simulation?

Large-eddy simulation (LES) is a mathematical model for turbulence used in computational fluid dynamics. It was initially proposed in 1963 by Joseph Smagorinsky to simulate atmospheric air currents. In most industrial applications, fluid flow is turbulent, and in other words, flow velocity magnitude and direction fluctuate during time. There are three models for investigating turbulence effects. Direct numerical simulation (DNS) in DNS no modeling required. DNS solving is not practical for simulating industrial work that Reynold’s number is very high.

The computational cost of DNS is related to the cube of the Reynolds number. The computational price of this model is very high and is not proposed for industrial work. Needs an increased number of elements and consequence high-performance CPU (HPC) and RAM. In applications that detail fluid flow and eddies are essential, we must use DNS. Another method is Reynolds Average Naiver Stokes (RANS). Using this method, we find the effect of turbulence and eddies; in other words, we will find the Reynolds stress magnitude and turbulence viscous. The computational cost of this model is lower than DNS and can be simulated in a steady state.

There is another model that can be solved in some industrial work that we should know more about eddies and vortexes. This model is used for finding significant eddies behavior. We know that large eddies transfer most passive scalar, mass, and momentum. Necessary eddies behavior is more related to particular problems and geometry and boundary conditions than exceptional work, but minor eddies behavior is more universal. So we can simulate small eddies by various models such as the RANS model (k-epsilon, k-omega, and so on).

When we simulate the LES model, we should use the transient model and finer mesh compared to RANS models such as K-omega and k-epsilon. Also, we should use a smaller mesh size, and consequently, the number of mesh is higher. So the total computational cost is high, and we need a high-performance computer. But the computational price of this model is lower than DNS.

Large Eddy Simulation



MR-CFD Large-eddy simulation Services

Having several years of experience in simulating a wide range of problems in various CFD fields using Fluent software, the MR-CFD team is ready to offer extensive modeling, meshing, and simulation services. Simulation Services for LES are categorized as follows:

  • CFD Simulation of high-Mach airflow over aerial structures
  • CFD Simulation of fire spread and combustion using LES method
  • Application of LES method in building simulations including pedestrian-level wind comfort, near-field pollutant dispersion, urban thermal environment, natural ventilation of buildings, and indoor airflow

You may find the related products in the aforementioned categories in our CFD shop by clicking on the following link:

Our services are not limited to the mentioned subjects, and the MR-CFD team is ready to undertake different and challenging projects in the LES field ordered by our customers. You can consult with our experts freely and without charge at first, and then order your project by sending the details of the problem to us using the following address.

[email protected]

By entrusting your project to the MR-CFD team, you will not only receive the related project’s files (Geometry, Mesh, Fluent files). Also, you will be provided with an extensive tutorial video demonstrating how you can create the geometry, mesh, and define the needed settings in the Fluent software all by yourself. And these all come with post-technical support from the MR-CFD team.

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