Index of /channels/data/spectra/re950/2D
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INFORMATION ABOUT THE RE950 2D SPECTRA FILES
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There are 18 files,
Re950.spe.j?? ---> Spectrum at heigth ??
FOR CONVENIENCE, some of the header information from all the spectra are
collected in the text file "spsumm.950.txt", in this directory
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The files are written in the standard BINARY FORTRAN UNFORMATTED fashion, and
the Byte ordering of each 4-Byte word is LITTLE ENDIAN.
We have stored the 2D spectra at different wall-distances.
If you try to read these files in MATLAB or C, take into account that IFORT adds 4
bytes at the end and beggining of each record
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The 1st record is a header with the following information:
time,re,alp,bet,mx,my,mz,nplan,nacum,jind,nvar
utau (4 Bytes real) : Friction velocity in computational units
re (4 Bytes real) : Reynolds number based on"some" bulk mean velocity
in the channel (actually 1/nu is comput. units).
alp (4 Bytes real) : A parameter which gives the length
of the computational box. Lx/h=2*pi/alp.
bet (4 Bytes real) : A parameter which gives the width
of the computational box. Lz/h=2*pi/bet.
mx (4 Bytes integer) : Number of Fourier Galerkin modes in the
streamwise direction.
my (4 Bytes integer) : Number of grid points in the
wall-normal direction.
mz (4 Bytes integer) : Number of Fourier Galerkin modes in the
spanwise direction.
nplan(4 Bytes integer) : Total number of spectral planes collected
nacum(4 Bytes integer) : Number of fields that have been accumulated to
average the spectra (this was lost, set to 1).
jind (4 Bytes integer) : Index of spectrum in jsp (see 2nd record).
nvar (4 Bytes integer) : Number of spectral quantities collected. In most cases
seven, except for Re2000 where there are 8, see below)
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The 2nd record is a header with the following information:
(jsp(j), j=1,nplan) (4 Bytes integer): indexes corresponding to the
position in the grid of the planes of the spectra.
The corresponding coordinates are
(y(j)/h, j=1,nplan) (4 Bytes real): wall-normal coordinates of all spectra.
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The following nvar records have:
((sp(ix,iz),ix=1,nx1), iz=1,nz1) (4 Bytes real):
2D spectrum at y(jind)
nx1=mx/2, nz1=(mz+1)/2
and
var = 1 -> uu
var = 2 -> vv
var = 3 -> ww
var = 4 -> Re(u*v)
var = 5 -> Ox*Ox
var = 6 -> Oy*Oy
var = 7 -> Oz*Oz
var = 8 -> Im(u*v) ONLY for Retau=2000 !!!
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WARNING: The final spectra is sp = sp/nacum
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If you use these data, please cite
Juan C. del Alamo, Javier Jimenez, Paulo Zandonade and
Robert D. Moser (2004) "Scaling of the energy spectra
of turbulent channels", J. Fluid Mech. vol 500, pp 135-144
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juanc@torroja.dmt.upm.es
sergio@torroja.dmt.upm.es
jimenez@torroja.dmt.upm.es