Large-eddy simulation formulation and implementation in HYDRA
This report provides the equation formulation for a large-eddy simulation (LES) approach and Smagorinsky subgrid-scale (SGS) model for incompressible flow using the finite element method (FEM). This report also outlines the model implementation in the computer code HYDRA and the results of a coding check. The check was accomplished by running simple two- and three-element problems for a specified velocity field. The values of the eddy viscosity (the coefficient of proportionality in the SGS eddy diffusion model), the SGS diffusion term, and overall diffusion term (molecular plus SGS plus balancing tensor diffusivity) were compared to known hand-calculated values. Coding checks are best done by comparing the code-calculated solution to known analytical solutions. However, with LES turbulence modeling, these analytical solutions do not exist. It is also impossible to determine that the eddy viscosity is free of coding errors when performing code validation by comparing the LES to direct numerical simulations (DNS) (i.e., fine discretization with no turbulence model) or experimental results. Therefore, the coding checks presented here for a specified velocity field are necessary.
- Research Organization:
- Lawrence Livermore National Lab., CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 188939
- Report Number(s):
- UCRL-ID--122543; ON: DE96004792
- Country of Publication:
- United States
- Language:
- English
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