les of turbulent flows: lecture 4 (me en 7960- 003)
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LES of Turbulent Flows: Lecture 4(ME EN 7960-003)
Prof. Rob StollDepartment of Mechanical Engineering
University of Utah
Fall 2014
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LES Filters and their transfer functions
Real Space Filters Filter Transfer Function
Only the Gaussian filter is local in both real and wave space
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Filtering Turbulence (real space, cutoff filter)
Note: here (and throughout the presentation) we are using DNS data from Lu et al. (International Journal of Modern Physics C, 2008).
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Filtering Turbulence (real space, Gaussian filter)
Note: here (and throughout the presentation) we are using DNS data from Lu et al. (International Journal of Modern Physics C, 2008).
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Filtering Turbulence (real space, box filter)Note: here (and throughout the presentation) we are using DNS data from Lu et al. (International Journal of Modern Physics C, 2008).
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Filtering Turbulence (real space)Note: here (and throughout the presentation) we are using DNS data from Lu et al. (International Journal of Modern Physics C, 2008).
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Filtering Turbulence (wave space)
π/Δ2
π/Δ1
π/Δ2
π/Δ1
π/Δ2
π/Δ1
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Filtering Turbulence (wave space)
π/Δ1 π/Δ2
Comparison between different filters
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We can use our filtered DNS fields to look at how the choice of our filter kernel affects this separation in wavespace
Decomposition of Turbulence for real filters
π/Δ π/Δ
Resolved scales SGS scales
Resolved SFS
Resolved scales SGS scales
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