Documentation du code de simulation numérique SUNFLUIDH

This data setup allows the user to set the time parameters of the code in order to :

• perform the numerical simulation (time step, stopping criteria…)
• record the results associated to time series of probes, instantaneous quantity fields, statistical quantities.
• record the backup/restart files

• Type : Integer Value
• This data indicates how is initialized the simulation :
  • 0 : The simulation starts from the beginning corresponding to an initialization state.
  • 1 or 2 : The simulation is resumed from a temporary backup file recorded during the previous simulation. Useful to resume a simulation suddenly interrupted. As the temporary backup file a regularly removed during a simulation, only the two last files created by the code are available. They correspond to the number 1 or 2. The number of last file created is recorded in the file num_sav_xxxxx.d (xxxxx correspond to the MPI process number when the simulation is performed in a domain decomposition approach).
  • 3 : The simulation is resumed from the last backup file built during the last time step of the previous simulation. Useful to continue a incompleted simulation. The number 3 must be present in the file num_sav_xxxxx.d (proof that the previous simulation is correctly completed), otherwise the numbers 0, 1 or 2 (related to the previous cases) will be present.

• Type : Boolean value
• Activation of the stopping criterion for steady flow (based on the L2-norm of the time variation of quantities).

• Type : Real value
• When the L2-norm of the time variation of quantities is lower than this value, the simulation is stopped and the solution corresponds to a steady flow.

• Type : Integer value
• This value is the maximum of time iterations performed by the code before stopping.

• Type : Real value
• This value is the physical time limit reached by the simulation before stopping.

• Type : Integer value
• Selection of way to define the numerical time step :
  • 0 : The time step is constant and defined by the user by means of the variable “Timestep_max” (see further).
  • -1 : The time step evolves lineraly between the values given by “Timestep_min” and “Timestep_max”. The range of variation is defined by the variable “Iterations_For_Timestep_Linear_Progress” (in time iteration number, see further).
  • 1 : The time step is calculated for each time iteration by means of the CFL parameter. The CFL parameter can be constant, it is thus defined by the variable “CFL_Max”.
    It can also evolve linearly between the values given by “CFL_Min” and “CFL_Max”. The range of variation is defined by the variable “Iterations_For_Timestep_Linear_Progress” (in time iteration number, see further).

• Type : Real value
• Minimum value of the time step. This variable can be omitted when the time step is constant.

• Type : Real value
• Maximum value of the time step. This variable set the value of the time step when it is constant.

• Type : Real value. This variable can be omitted when the time step is constant.
• Minimum value of the CFL parameter.

• Type : Real value
• Maximum value of the CFL parameter. This variable set the value of the CFL parameter when it is constant.

• Type : Integer value
• Number of time iterations over which the CFL parameter or the time step can evolve linearly. When the time step or the CFL parameter are constant, this variable must not set to a value greater than 1. It could actually be omitted (this default value is 1).

• Type : Integer value
• This variable defines the recording rate, in time iteration units , of the backup files (for instance, when “Simulation_Backup_Rate=1000” a data backup is carried out for all time iteration numbers that are a multiple of 1000).

• Type : Real value
• This variable defines the recording rate, in time units , of the selected instantaneous fields (for instance, when “Field_Recording_Rate=1.5” a file containing the selected instantaneous fields is created all time that is a multiple of 1.5).