===== 3D turbulent channel flow at $Re_{\tau}= 180$ =====


**Author** :  Y. Fraigneau  CNRS-LIMSI (yann.fraigneau@lisn.fr) \\
**Date**   :  June 2020\\
**Simulation type** : DNS ([[https://sunfluidh.lisn.upsaclay.fr|Sunfluidh code]])
**Location** : DATABASE_CHANNELFLOW_RETAU180_DNS \\
**Status ** : Free access \\
**Data size** : ~ 13 Gb \\

{{:datasetmeca:chflow_ret590.png?900|}}

\\

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==== Simulation settings ====
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=== 2D sketch ===

{{ :datasetmeca:sketch_chflow180.jpg?800 |}}

=== Referential : cartesian geometry ===
   - axes   :
      * x(i) : downstream direction
      * y(j) : normal direction
      * z(k) : spanwise direction
    - origin :
      * $x_0= 0$ : left down corner
      * $y_0= 0$ : left down corner
      * $z_0= 0$ : left down corner

===  Reference scales ===

   * Density           : mass density of the fluid ($\rho_0$)
   * Length            : half height of the channel ($h=\frac{H}{2}=1$)
   * Velocity          : wall friction velocity ($u_*$)
   * Dynamic viscosity : dynamic viscosity of the fluid ($\mu_0$)
   * Reynolds number : $Re_H= \frac{\rho_0.u_*.h}{\mu_0}= 180$

=== Non-dimensionalised data ===

   * velocity   : $U^*=\frac{U}{u_*}$ 
   * density    : $\rho^*= \rho/\rho_0= 1$
   * coordinates : $x*=\frac{x}{h}$, $y^*=\frac{y}{h}$ , $z^*=\frac{z}{h}$

=== Computational domain ===

   - **Domain scope**
      * Downstream direction(x) : $L_x^*= 2\pi$
      * Normal direction    (y) : $H^*= 2.0$
      * Spanwise direction  (z) : $l^*= \pi$
  - **Boundary conditions**
      * Wall conditions : Top and low walls of the domain
      * Periodicity     : lateral ends of the domain in $x$ and $z$ directions
  - **Spatial resolution**   :
       * Grid   :  $96 \times 128 \times 96$ (1.179.648 cells over the domain)
       * About cell-size   
          * $\Delta x_{min}^*= \Delta x_{max}^*= 6.545 \,10^{-2}$ (downstream direction)
          * $\Delta y_{min}^*= 2.780\, 10^{-4} \quad \Delta y_{max}^*= 3.088 \,10^{-2}$ (normal direction)
          * $\Delta z_{min}^*= \Delta z_{max}^*=  3.2725 \, 10^{-2}$ (normal direction)

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==== Data features ====
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   * **Time series from probes** 
      * Physical quantities : velocity components along x, y and z directions (u,v,w) and  pressure (p)
      * 7 probes
      * Time step= 0.0126 time unit
      * Time range : 97.09 to 301.09 time units
      * Locations (In vertical plan at $z=1.57$)
          * Xi= 3.14, Xj= 0.25 , Xk= 1.57 
          * Xi= 3.14, Xj= 0.75 , Xk= 1.57
          * Xi= 3.14, Xj= 1.00 , Xk= 1.57
          * Xi= 3.14, Xj= 1.25 , Xk= 1.57
          * Xi= 3.14, Xj= 1.50 , Xk= 1.57
          * Xi= 3.14, Xj= 1.75 , Xk= 1.57
        
      * File name (per physical quantity): x_ins_00000.d   with x= u,v,w,p

   * **3D snapshots** 
         * Instantaneous fields : velocity components in x, y and z directions (U,V,W) and pressure (P)
         * Recording rate : 0.3 time units 
         * Time range from 97.39 to 301.09 time units 
         * File name : res_xxxxx_yyyyyyy.d  (xxxxx : MPI subdomain ID, yyyyyyy : Time ID)
               * MPI subdomain ID: 0
               * Time ID : from 11 to 690

   * **Statistics** 
      * fields : (i,j : indexes of direction x, y or z)
            * Mean fields of velocity components (<Ui>) and pressure (<P>)
            * Mean fields of quadratic quantities (<P2>, <UiUj>)
      * Time average computation
      * Time startup        = 100.0 time units 
      * Time range per file = 25.0 time units 
      * Total time range from  100.0 to 300 time units
      * file name : rst_xxxxx_yyyyyyy.d  (xxxxx : MPI subdomain ID, yyyyyyy : Time ID)
            * MPI subdomain ID : 0
            * Time ID : from 1 to 35

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==== Database organisation ====
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**Data size** : ~ 13 Gb \\
**Main directory** : /vol/DATABASE_MECA/DATABASE_CHANNELFLOW_RETAU180_DNS \\
For more details about files, see the [[https://sunfluidh.limsi.fr|the wiki doc of Sunfluidh]]

=== Directories & files ===

    /GRID : contains all ASCII files about grid setup
    
       input data file         : data_meshgen.d
       report on grid features : report_meshgen.d
       grid files for sunfluidh: maillx.d, mailly.d, maillz.d
       check files (ASCII)     : check_mesh_I.d,check_mesh_J.d,check_mesh_K.d
                                 (3 columns : indices, cell-face coordinates, cell size)
                                 
    /DATASETUP       : ASCII files
     
     input data file for sunfluidh : input3d.dat
    
    /TIMESERIES : contains time series recorded over the time range [16.64 ; 199.44]
                  ASCII files : x_ins_yyyyy.d   with x= u,v,w,p
                  time series files are sliced in storage directories CAS-MPI200-n (n from 5 to 50)
     
    /SNAPSHOTS  : snapshots binary files res_xxxxx_yyyyyyy.d
                  files stored in archive files : res_yyyyyyy.tar for each time ID
                 
    /STATISTICS : statistics binary files files rst_xxxxx_yyyyyyy.d
                  files stored in archive files : res_z.tar , z is an ID number (from 1 to 35)
                        
    /RESTART_AR : backup/restart archive save.tar at time 301.09
    
    /FROM_COMPUTATION : regroups some files related to the simulation : checkcalc_00000.dat and checkdata_00000.dat
    

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