Table des matières

Sunfluidh output files

Type of files

Several types of output files exist :

The file formats are ASCII or BINARY.
The binary files related to the instantaneous and statistical fields can be converted to an appropriate format for data visualization (with the softwares Tecplot or Paraview) by using the in-house software VISFIELD .
It is also possible to upload the data in Matlab or Python.

Probe files

The name of file is defined following the template : “N_ins_yyyyy.d”.

  • These files are written in ASCII format and data are ordered in columns.
  • The first column is the time and the others are the time series of the physical quantity specified in the file name. Other columns are linked with probe locations.
  • The velocity components are interpolated at the center of cells.

The data setting is defined in the file “input3d.dat” by means of the namelists:

Instantaneous field files

The name of file is defined following the template : “res_yyyyy_xxxxxxx.d”

  • These files are written in binary format.
  • Each recorded field includes the ghost-cells surrounding the computational domain (or subdomains for MPI computing).
  • Each file contains a cell-centered coordinate set
  • The velocity components are located at the center of the cell-faces (the location used during the computation, see "Overview of key points for using Sunfluidh").

The data setting is performed in the file “input3d.dat” with the namelists :

"Slice" files

The name of file is defined following the template : “slice_Id_Dir_yyyyy_xxxxxxx.d”

These files are written in binary format.

The data setting is performed in the file “input3d.dat” with the namelists :

  • When the variable “Slice_Gathering_Enabled= .true.” in the namelist Field_Recording_Setup, every “slice” data split over several MPI subdomains are gathered and recorded in the same file named “slice_Id_Dir_xxxxxxx.d”(“yyyyy” is not considered).
  • Each file contains a cell-centered coordinate set.
  • The velocity components are interpolated at the center of cells. Their position is directly given by the cell-centered coordinate set.

"Space-averaged" files

The name of file is defined following the template : “spav_slice_Dir_xxxxxxx.d”

  • These files are written in binary format.
  • Each file contains a cell-centered coordinate set.
  • The velocity components are interpolated at the center of cells. Their position is directly given by the cell-centered coordinate set.

The data setting is performed in the file “input3d.dat” with the namelists :

Statistical field files

The name is defined following the template : “rst_yyyyy_xxxxxxx.d”

  • These files are written in binary format (double precision for the real values).
  • Each recorded field includes the ghost-cells surrounding the computational domain (or subdomains for MPI computing).
  • Each file contains a cell-centered coordinate set.
  • The velocity components are interpolated at the center of cells. Their position is directly given by the cell-centered coordinate set.
The term “statistics” generally means the computation of time averages :$$ \overline{f(x_i,x_j,x_k,z)}= \frac{1}{T}\sum_{n=1}^{n=N_t} f(x_i,x_j,x_k,t_n) \Delta t$$

However, the computation of a time average can be sometime coupled with a space average procedure in order to improve the accuracy on statistics. For example, a field f(x_i,x_j,x_k,t_n) can be averaged in time and space along a specific direction, which is generally an homogeneous direction with periodical conditions (e.g. the i-direction). This yields the reduced mean field $$ <\overline{f(x_j,x_k)}>= \frac{1}{N_i.T}\sum_{n=1}^{n=N_t}\sum_{i=1}^{i=N_i} f(x_i,x_j,x_k,t_n) \Delta t$$

The data setting is performed in the file “input3d.dat” with the namelists :

Backup files

Three types of files exists for data used for a restart procedure :

These binary files are only used by the code to resume the simulation from a backup. To resume a simulation from a previous computation, set the variable “Restart_Parameter=3” in the namelist Simulation_Management. This is the standart usage. However, if the previous simulation was not correctly completed, the code can restart from a temporary backup according to the value n recorded in the file “num_sav_yyyyy.d' (n= 1 or 2).
If “Restart_Parameter=0”, the code starts the simulation from initial conditions defined in the input data file. For this, see the following namelists :

It also exists two kinds of files for the backup of statistical quantities :

The checking files

There is four type of checking files :

checkdata_yyyyy.d : This ASCII file contains a transcription of simulation conditions (how information from the input dataset has been performed by the code). For MPI computation, each subdomain create its own file although most of relevant information is written in the file checkdata_00000.d.
checkcalc_yyyyy.d : This ASCII file contains some relevant information regularly collected during the simulation. This information relates some instantaneous data resulting from the simulation at a time $t_n$. This allows to check the behavior of the simulation. The recording rate of the information collected is set up with the data “Simulation_Checking_Rate” (in time iteration unit) in the namelist Simulation_Management
The main information is :


check_namelist_data.d : This ASCII file contains all the namelists present in the input data file including the full data setup associated at each namelist, i.e. each data explicitly set by the user and all other data with their own default value.
resid_L2_Li.d : This ASCII file contains time series of the $L_2$-norm and the $L_{\infty}$-norm built from the time derivatives of the velocity components, temperature and mass species fractions (when they are considered in the simulation).
The $L_2$-norm is defined as :$$ R_{L_2}(t_n)= \frac{1}{N_i.N_j.N_k}[\sum_m \sum_{i,j,k}(C_m\frac{\Phi_m(i,j,k,t_n)-\Phi_m(i,j,k,t_n-\Delta t)}{\Delta t})^2]^{\frac{1}{2}}$$ where $m$ is the index related to the physical quantities considered (U,V,W,T, …), $N_i$,$N_j$ and $N_k$ are the numbers of cells along each direction and $C_m$ a normalization coefficient. The $L_\infty$-norm is defined as :$$ R_{L_\infty}(t_n)= Max_{i,j,k}\big(\sum_m C_m\frac{\Phi_m(i,j,k,t_n)-\Phi_m(i,j,k,t_n-\Delta t)}{\Delta t}\big)$$

The recording rate used for building the time series is the same as that used for the file “checkcalc_yyyyy.d”.
$L_2$-norm is used as stopping criteria for the computation of a steady solution.