===== 2D flow around a heated square-cylinder - $Re_{h}= 50$, $Ra= 5\; 10^6$ =====

<note>
A heated square-cylinder is placed in a channel flow
</note>

**Author** :  Y. Fraigneau, LISN, UMR CNRS 9015 (yann.fraigneau@lisn.fr) \\
**Date**   :  June 2019\\
**Simulation type** : DNS (code Sunfluidh -- [[https://sunfluidh.lisn.upsaclay.fr|Sunfluidh code]]) \\
**Location** : /DATABASE_2DFLOW_AROUND_HEATED_SQUARECYLINDER_DNS \\
**Status** : Free access for laboratory members, on request for external members \\
**Data size** : ~ 1 Gb \\

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

[[https://sunfluidh.lisn.upsaclay.fr/doku.php?id=sunfluidh:sunfluidh_gallery#d_flow_past_a_heated_square-cylinder| A video is available here ]]

[[:start|Come back to first page]]
-----
==== Simulation settings ====
----

=== 2D sketch ===

{{ :datasetmeca:sketch_config_heatcyl.jpg?600 |}}

=== Referential : cartesian geometry ===
   - axes   :
      * x(i) : downstream direction
      * y(j) : normal direction
    - origin : lower left corner of the computational domain
      * $x_0= 10h$ 
      * $y_0= -6h$ 

===  Reference scales ===

   * Density           : mass density of the fluid ($\rho_0$)
   * Lengths           : cylinder size ($h$) and $H_u= 10h$ the distance between the domain's top and the square-cylinder's top.
   * Velocity          : velocity at inlet ($U_0$)
   * Dynamic viscosity : dynamic viscosity of the fluid ($\mu_0$)
   * thermal diffusivity :  ($\kappa_0$)
   * Reynolds number   : $Re_h= \frac{\rho_0.U_0.h}{\mu_0}= 50$
   * Rayleigh number   : $Ra_{Hu}=  \frac{\rho_0.\beta.g\Delta T.H_u^3}{\mu_0 \kappa_0}= 5\;10^6$
=== Non-dimensionalised data ===

   * velocity   : $U^*=\frac{U}{U_0}$ 
   * density    : $\rho^*= \rho/\rho_0= 1$
   * coordinates : $x*=\frac{x}{h}$, $y^*=\frac{y}{h}$
   * temperature : $T^*=\frac{T-T_c}{T_h-T_c}$ ($T_h$ and $T_c$ are respectively the temperature imposed at the cylinder's walls and the temperature at the inlet and channel's walls)

=== Computational domain ===

   - **Domain scope**
           - computational domain size (channel flow)
                * Downstream direction(x) : $L_x^*= 50.0$ (upward part $L_u= -10$, downward part $L_d=40$)
                * Normal direction    (y) : $H*= 20.0$
          - heated square cylinder 
                * size: $h^*= 1$
                * wall temperature T_h^*= 1

  - **Boundary conditions**
      * Inlet           : imposed pressure uniform velocity ($U_0=1$)
      * Outlet          : Orlansky type
      * Bottom and top conditions  : walls at (T_c^*=0)
  - **Spatial resolution**
       * mesh size : $512 \times 256 $  (131.072 cells)
       * About cell-size   
          * $\Delta x*$ : from $0.03125$ to $0.723$ (downstream direction)
          * $\Delta y*$ : from  $0.03125$ to $0.187$ (normal direction)

[[:start|Come back to first page]]
----
==== Data features ====
----

   * **Time series **
          * Physical quantities : velocity components along x and y directions (u,v) and pressure (p)
          * 1 probe
          * Time step= $\approx 6 \,10^{-2}$ time unit (irregular time step)
          * Time range : 250 time units
          * Location : Xi= 20.0 , Xj=2.0 
          * File name (per physical quantity): x_ins_00000.d   with x= u,v,t


   * **3D snapshots**
         * Instantaneous fields : velocity components in x, y and z directions (U,V), the pressure (P) and the phase function related to the body motion (TRACE)
         * Recording rate : 1 time unit
         * Time range from from 20.0 to 250.0 time units
         * File name : res_xxxxx_yyyyyyy.d 
               * MPI subdomain ID: from 0 to 3 (case with MPI domain decomposition)
               * Time ID : from 0 to 250

 
[[:start|Come back to first page]]
----
==== Database organisation ====
----

**Data size** : ~ 3 Gb \\
**Main directory** : /vol/DATABASE_MECA/DATABASE_2DFLOW_HEATED_SQUARRECYLINDER_DNS \\

Directories & files

                                 
    /DATASETUP       : ASCII files
                       input data file for sunfluidh : input3d.dat (and input3d.dat_mpi4 for the case with MPI domain decomposition)
    
    /GRID            : ASCII files
                       input data file         : data_meshgen.d
                       grid files for sunfluidh: maillx.d, mailly.d, maillz.d (sequential case)
                                                 mesh.tar (archive containing grid files for a domain decomposition with 4 MPI processes)
     
    /SNAPSHOTS       : snapshots binary files res_xxxxx_yyyyyyy.d
    /SNAPSHOTS_MPI4  : snapshots resulting from a domain decomposition with 4 MPI processes
    
    /TIMESERIES      : ASCII files
                       u_ins_00000.d , v_ins_00000.d and t_ins_00000.d (timeseries of the velocity components and temperature from probe)

                 
[[:start|Come back to first page]]