Numerical methods for Large Eddy Simulation
This training session allows participants to understand the underlying basics of Large Eddy Simulation (LES): numerics, boundary conditions, LES closures and combustion modeling. The CFD code AVBP (version 6.2) co-developed by CERFACS and IFPEN is used for hands-on to compute both academic and realistic configurations of reacting compressible flows.
| Target participants:
This training session is for engineers, physicists, computer scientists and numerical analysts who wish to learn to useLES and to manipulate a CFD code dedicated to LES. Prerequisites: Unix, Fortran, numerical simulation. Scientific contact: Eleonore RIBER Fee: - Public staff: 1500 € - CERFACS shareholders/NRS/INRIA staff: 750 € - Students: 250 € |
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| Program | ||
| (Every day from 9h to 17h30) | ||
| Day1 - Day2 - Day3 - Day4 - Day5 | ||
| Day 1 - Introduction | ||
| 9h00 | Welcome and coffee | |
| 9h45 | LES of reacting compressible flows - Introduction
The differences between RANS and LES. The codes for LES. |
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| 10h45 | How does AVBP work
Files - scripts - general organization. |
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| 11h30 | Installation on computers - accounts - computer organization | |
| 14h00 | How does HIP work - Description of HDF format | |
| 14h30 | Hands-on work on computers: examples of LES post-processing
Non-reacting and reacting (stabilised flames and ignition) cases. Run temporal post-processing, snapshots (using Paraview), unsteady diagnostics, etc. |
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| Day 2 - Numerical Schemes | ||
| 9h00 | Dissipation and dispersion of waves
Introduction using a simple second order scheme. Impact of scheme order on result accuracy. Scheems required for LES. |
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| 9h45 | Implementation of numerical schemes in a LES code | |
| 10h30 | Hands-on: measurement of dispersion and dissipation on acoustic wave propagation | |
| 14h00 | Hands-on: simulation of two-dimensional vortices
Effects of mesh and scheme. |
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| Day 3 - Boundary conditions | ||
| 9h00 | Boundary conditions in compressible flows: characteristic method
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| 9h45 | Implementation of boundary conditions in a LES code
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| 10h30 | Hands-on: simulation of one-dimensional acoustic waves reaching non-reflecting boundaries
Generation of propagating acoustic waves. |
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| 14h00 | Hands-on: manipulation of boundary conditions to mimic reflexions or to produce non-reflecting conditions
Applications to vortices going through outlet. |
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| Day 4 - Combustion | ||
| 9h00 | LES of reacting flows: thermodynamics, kinetics, laminar flames and turbulent combustion model
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| 10h30 | Hands-on: simulation of one-dimensional laminar flame with and without flame thickening | |
| 14h00 | Hands-on: simulation of a forced two-dimensional laminar flame | |
| Day 5 - Morning - Subgrid scale and wall modelling | ||
| 9h00 | Closure models for LES and wall modelling
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| 10h30 | Hands-on: post-processing LES of turbulent pipe flow.
Effect of subgrid scale model, wall model and grid refinement. |
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| Day 5 - Afternoon - Turbulent flames using C3S | ||
| 14h00 | Hands-on: setting up a complete run for a turbulent reacting configuration (EKT) using the C3S GUI.
Starting from an existing mesh (Centaur) and an initial zero velocity field, setting of boundary conditions and checking of the beginning of the filling phase. Ignition of the EKT configuration starting from a stabilized non-reacting flow. Analysis of the stabilised reacting flow. |
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