A physics-inspired alternative to spatial filtering for large-eddy simulations of turbulent flows

Large-eddy simulations (LES) are widely used for computing high Reynolds number turbulent flows. Spatial filtering theory for LES is not without its shortcomings, including how to define filtering for wall-bounded flows, commutation errors for non-uniform filters and extensibility to flows with addi...

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Bibliographic Details
Published in:Journal of fluid mechanics 2022-03, Vol.934, Article A30
Main Author: Johnson, Perry L.
Format: Article
Language:English
Subjects:
Commutation
Complexity
Errors
Fluid dynamics
Fluid flow
Fluid mechanics
Free flow
High Reynolds number
Incompressible flow
Interfaces
JFM Papers
Large eddy simulation
Multiphase flow
Oceanic eddies
Partial differential equations
Physics
Procedures
Reynolds number
Simulation
Spatial filtering
Theories
Turbulent flow
Velocity
Vortices
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Summary:Large-eddy simulations (LES) are widely used for computing high Reynolds number turbulent flows. Spatial filtering theory for LES is not without its shortcomings, including how to define filtering for wall-bounded flows, commutation errors for non-uniform filters and extensibility to flows with additional complexity, such as multiphase flows. In this paper, the theory for LES is reimagined using a coarsening procedure that imitates nature. This physics-inspired coarsening approach is equivalent to Gaussian filtering for single-phase wall-free flows but opens up new insights for both physical understanding and modelling even in that simple case. For example, an alternative to the Germano identity is introduced and used to define a dynamic procedure without the need for a test filter. Non-uniform resolution can be represented in this framework without commutation errors, and the divergence-free condition is retained for incompressible flows. Potential extensions of the theory to more complex physics such as multiphase flows are briefly discussed.
ISSN:0022-1120
1469-7645
DOI:10.1017/jfm.2021.1150