Results for case (not set)

Code: Code_Saturne

Version: 2.0-beta2

Authors: E. Moreau

Method and Numerical Options

Six different calculations have been carried out testing three different sub-grid models (Smagorinsky, Germano Dynamic model and WALE). The calculations are carried out starting from a initial velocity field evaluated accordingly to a defined reference spectrum. Two different spectra are used: a truncated and a filtered. The filtered spectrum is obtained using a Gauss filter with a filtered width equal to twice the cubic root of the cell volume. All the calculations are carried out using the Green-Gauss theorem for the reconstruction of the gradient (IMRGRA = 0). For the convective scheme a pure central (BLENCV=1), without the test on the slope (ISSTPC=1).

Models

Smagoringky, Germano Dynamic, WALE

Mesh

The domain is composed by a cube with length of the edge equal to %$5.12\,m$%. A structured conformal mesh is used with 128 cells in each direction.

Description of the results files

The obtained spectra are compared with the experimental results reported in [1]. The below table reports the xml file, the fortran and the results files.For every single section the file contains:
  1. Wave length
  2. Energy spectrum

Table with sources and results Mesh INIT Filtered INIT Truncated
Dynamic xml/SRC E Filtered E truncated
Smagorinsky xml/SRC E Filtered E truncated
WALE xml/SRC E Filtered  

Boundary conditions

Periodicity is employed in all three directions.

Reference Publications

  1. Kang H.S., Cherster S., Meneveau C.,Decaying turbulence an active-grid-generated flow and comparisons with large-eddy-simulation. J. Fluid Mech., vol 480, pp. 129-160, 2003.

Additional information (links, pictures, etc.)

On the following figures, the comparison between 1.3 and 2.0 models gives identical results, in agreement with the Gaussian-filtered spectrum (leading to the hypothesis that Code_Saturne's filter behaves like a Gaussian filter).

However, the new WALE model does not behave correctly for low frequency, this should be investigated further.

station48_128_en_conv.png
Fig. 1: Spectra for the DIT at station 48



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Topic attachments
I Attachment Action Size Date Who Comment
elsegz DYN.tar.gz manage 25.4 K 2010-10-01 - 10:37 StefanoRolfo DIT files
elsedat Dy_filt.dat manage 1.4 K 2010-10-01 - 10:37 StefanoRolfo DIT files
elsedat Dy_trun.dat manage 1.4 K 2010-10-01 - 10:37 StefanoRolfo DIT files
elsegz SMAG.tar.gz manage 18.4 K 2010-10-01 - 10:37 StefanoRolfo DIT files
elsedat Smag_filt.dat manage 1.4 K 2010-10-01 - 10:37 StefanoRolfo DIT files
elsedat Smag_trun.dat manage 1.4 K 2010-10-01 - 10:37 StefanoRolfo DIT files
elsegz WALE.tar.gz manage 34.2 K 2010-10-01 - 10:37 StefanoRolfo DIT files
elsedat WALE_filt.dat manage 1.4 K 2010-10-01 - 10:37 StefanoRolfo DIT files
pngpng station48_128_en_conv.png manage 84.5 K 2010-09-30 - 17:52 StefanoRolfo DIT spectra station 48
elsegz vitini_f.tar.gz manage 39477.0 K 2010-10-01 - 10:37 StefanoRolfo DIT files
elsegz vitini_nf.tar.gz manage 39538.0 K 2010-10-01 - 10:37 StefanoRolfo DIT files
Topic revision: r7 - 2011-09-02 - 14:11:36 - DavidMonfort
 

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