```
\=======================================================================
INFORMATION ABOUT THE DNS DATABASE
(HDF5 FILES)
\=======================================================================
This directory tree contain some of the restart files of a direct
numerical simulations of fully developed ZPG Boundary Layer flow
(Re\_theta=2780-6650). Details are offered below.
The algorithm used is presented in:
\- M. P. Simens, J. Jimenez, S. Hoyas, Y. Mizuno
"A high-resolution code for turbulent boundary layers"
Journal of Computational Physics
Volume 228, Issue 11, 20 June 2009, Pages 4218-4231
\- G. Borrell, J.A. Sillero, J. Jimenez
"A code for direct numerical simulation of turbulent boundary layers
at high Reynolds numbers in BG/P supercomputers"
Computers & Fluids, Volume 80, 10 July 2013, Pages 37-43
The data is discussed in:
\- J.A. Sillero, J. Jimenez, R.D. Moser
"One-point statistics for turbulent wall-bounded flows at Reynolds
numbers up to \\delta^+\\approx2000"
Phys. Fluids 25, 105102
\-----------------------------------------------------------------------
STRUCTURE OF THE FILES:
\-----------------------------------------------------------------------
The files are written in HDF5 format, which is supported by most of the
mathematical programs. For programming languages, libraries can be
downloaded for C, C++, Fortran 90, and Java interfaces.
The primitive variables {u,v,w,p} are stored in Fourier space as:
(kz,ny,nx) ---> ( Fourier - Physical -Physical )
For instance, one file contains:
Re Dataset {1} : Inverse of the viscosity used in the code,
which defines the scaling in which the code works.
Variable Dataset {SCALAR} : Variable recorded "u", "v", "w" or "p".
procs Dataset {536} : Number of nodes used to run the simulation.
(first element of the vector!)
cfl Dataset {1} : Courant?Friedrichs?Lewy condition at which the
simulation was run.
dt Dataset {1} : Time step in code units for this flow realization.
tiempo Dataset {1} : Time stamp in code units for this flow realization.
timeinit Dataset {1} : Initial time stamp in code units (=0).
lx Dataset {1} : Defines the streamwise length Lx of the box, in code units.
ly Dataset {1} : Defines the wall-normal length Ly of the box, in code units.
lz Dataset {1} : Defines the spanwise length Lz of the box, in code units.
nx Dataset {1} : Number of collocation points in the streamwise direction.
ny Dataset {1} : Number of collocation points in the wall-normal direction.
nz2 Dataset {1} : Half the number of complex Fourier Gallerkin modes in z-> K\_z\[0:nz2\]
We use the 2/3 dealiasing rule in z, so the number of collocation points in those directions are 3/2
times the number of Fourier Gallerkin modes, and the extra modes are padded with zeroes.
xout Dataset {1} : Location of the recycling plane.
um Dataset {536} : Mean streamwise velocity profile in code units at the recycling
station "xout".
y Dataset {537} : Non-uniform grid for the wall-normal distance; in code units.
Note that, because of the staggered grid: y=(-y1,0,y1,y2,....)
value Dataset {15361, 536, 2730} : Primitive variable in code units. The array is stored in single-precision
as \[1:2\*(nz2+1),1:Ny,1:Nx\], equivalent to the complex array \[Kz,Ny,Nx\]
SKETCH:
------v2------ \* y(3)=y1
| |
u2-----> x o w2,p2 x ----->
| |
| |
\==================v1=========== \* ======== y(2)=0;
| |
| |
u1-----> x o w1,p1 x ----->
| |
-------------- \* y(1)=-y1
Before final publication of a paper citing these data, please check this
site (http://torroja.dmt.upm.es/turbdata/blayers/high\_re) for an up-to-date reference.
Please report any problems with the data, queries or doubts to J.A. Sillero,
sillero@torroja.dmt.upm.es
```