sunfluidh:new_numerical_methods_setup_namelist
Différences
Ci-dessous, les différences entre deux révisions de la page.
Prochaine révision | Révision précédenteProchaine révisionLes deux révisions suivantes | ||
sunfluidh:new_numerical_methods_setup_namelist [2017/09/22 17:44] – créée yann | sunfluidh:new_numerical_methods_setup_namelist [2017/09/28 18:13] – [Poisson_NumericalMethod] yann | ||
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Ligne 1: | Ligne 1: | ||
- | ===== Namelist " | + | ===== Namelist " |
+ | __** Not for the release SUNFLUIDH_EDU**__ | ||
<WRAP info> | <WRAP info> | ||
- | This data setup is devoted to the selection of the numerical methods and schemes used in order to solve the conservation equations for velocity components, temperature, | + | This new data setup is also devoted to the selection of the numerical methods and schemes used in order to solve the conservation equations for velocity components, temperature, |
+ | The data are divided in three groups in order to define: | ||
+ | * the numerical method applied for solving the conservation equations (for velocity, temperature, | ||
+ | * the choice of advective or convective flux discretization (for 2nd order schemes only). The viscous, conductive or diffusive fluxes are always discretized with a centered 2nd order or 4th order scheme according to the previous choice. | ||
+ | * the numerical methods (and associated parameters) for solving the Poisson' | ||
</ | </ | ||
<note important> | <note important> | ||
- | Two versions | + | * This version allows the user to select the numerical methods by means of characters strings instead |
+ | * For the sake of clarity, the iterative method parameters used for solving the Poisson' | ||
+ | * [[HomeData_PoissonSolver_Namelist |HomeData_PoissonSolver]] for methods directly implemented in the code (" | ||
+ | * [[HypreData_PoissonSolver_Namelist |HypreData_PoissonSolver]] for methods provided by the HYPRE library | ||
+ | * [[Numerical_Methods_Examples |Click here]] to get __some examples__ illustrating how to use the namelists " | ||
</ | </ | ||
- | |||
- | |||
===== Full data set of the namelist ===== | ===== Full data set of the namelist ===== | ||
Ligne 19: | Ligne 27: | ||
<note important> | <note important> | ||
- | | + | |
- | * The partial diagonalization method (Poisson_NumericalMethod=" | + | * The partial diagonalization method (Poisson_NumericalMethod = " |
* The HYPRE library solvers for solving the Poisson' | * The HYPRE library solvers for solving the Poisson' | ||
+ | |||
</ | </ | ||
Ligne 30: | Ligne 39: | ||
===== Solving the conservation equations ===== | ===== Solving the conservation equations ===== | ||
----- | ----- | ||
- | ==== NS_NumericalMethod (strictly | + | ==== NS_NumericalMethod |
+ | (equivalent to " | ||
* Type: character string | * Type: character string | ||
* Selection of the numerical scheme for solving the conservation equations : | * Selection of the numerical scheme for solving the conservation equations : | ||
- | * " | + | |
- | * " | + | |
- | * " | + | |
- | * " | + | |
- | * " | + | |
- | * " | + | |
- | * " | + | |
- | * " | + | |
- | * " | + | |
- | * " | + | |
- | ==== Convective_Flux_Discretization_Type | + | ==== MomentumConvection_Scheme |
- | * Type : integer value | + | (equivalent to " |
+ | * Type : character string | ||
* Selection of the 2nd order spatial discretization for the convection flux in the momentum equations. The options are : | * Selection of the 2nd order spatial discretization for the convection flux in the momentum equations. The options are : | ||
- | | + | |
- | | + | |
- | | + | |
- | | + | |
- | | + | |
- | | + | |
- | | + | |
- | ==== Temperature_Advective_Flux_Discretization_Type | + | ==== TemperatureAdvection_Scheme |
- | * Type : integer value | + | (equivalent to " |
+ | * Type : character string | ||
* Selection of the 2nd order spatial discretization for the advection flux in the temperature/ | * Selection of the 2nd order spatial discretization for the advection flux in the temperature/ | ||
- | ==== species_Advective_Flux_Discretization_Type | + | ==== SpeciesAdvection_Scheme |
- | * Type : integer value. __** Not for the release SUNFLUIDH_EDU**__ . | + | (equivalent to " |
+ | * Type : character string. __** Not for the release SUNFLUIDH_EDU**__ . | ||
* Selection of the 2nd order spatial discretization for the advection flux in the species equations. The options are the same as previously. | * Selection of the 2nd order spatial discretization for the advection flux in the species equations. The options are the same as previously. | ||
==== Explicit_Solving_of_Density ==== | ==== Explicit_Solving_of_Density ==== | ||
Ligne 77: | Ligne 90: | ||
----- | ----- | ||
- | ==== Numerical_Method_Poisson_Equation | + | ==== |
- | * Type : Integer value | + | (equivalent to " |
+ | * Type : Character string | ||
* Selection of the numerical method for solving the Poisson equation in accordance to the projection method. The solution is the pressure time increment ($\Phi= P^{n+1}-P^{n}$, | * Selection of the numerical method for solving the Poisson equation in accordance to the projection method. The solution is the pressure time increment ($\Phi= P^{n+1}-P^{n}$, | ||
- | | + | |
- | | + | |
- | | + | |
- | | + | |
- | | + | |
- | ==== Iterative_Method_Selection (only if the SOR method is used) ==== | + | |
- | * Type : Integer value | + | |
- | * Select the algorithm used for solving the Poisson equation from an SOR method. These options are : | + | ==== Simulation control ===== |
- | | + | |
- | * 2 : The SOR method | + | We here resort to a specific namelist named " |
- | * 3 : The SOR method is based on the Gauss-Seidel algorithm with a two-color approach (Red-Black type). This method is used in the context of parallel simulations (MPI domain decomposition, | + | We specify here some parameters in order to define the numerical time step as well as stop criteria and recording rates related to backup and check files. |
- | ==== Number_max_Grid (multigrid method only) ==== | + | Two examples are given. |
- | * Type : Integer value | + | The first one corresponds to a simulation starting at t= 0 with a variable time step. |
- | * Maximum number of grid levels | + | |
- | ==== Number_max_Cycle (multigrid method only) ==== | + | |
- | * Type : Integer value | + | & |
- | * Maximum number of V-cycles permitted in the multigrid method. | + | Steady_Flow_Stopping_Criterion_Enabled |
- | ==== Number_Iteration | + | |
- | * Type : integer | + | |
- | * Number of iterations | + | |
- | ==== Relaxation_Coefficient | + | |
- | * Type : real value between | + | |
- | * over-relaxation coefficient used in the SOR method. | + | CFL_Max = 0.4 ,!--- Maximum |
- | ==== Convergence_Criterion | + | Iterations_For_Timestep_Linear_Progress= 100 , |
- | * Type : real value | + | |
- | * The nV-cycle procedure of the multigrid method is stopped | + | |
- | ==== Off_Set_Poisson_Source_term ==== | + | |
- | | + | The second example corresponds |
- | | + | |
+ | & | ||
+ | | ||
+ | | ||
+ | | ||
+ | | ||
+ | | ||
+ | | ||
+ | Iterations_For_Timestep_Linear_Progress= 100 ,!--- Number of time iterations over which the CFL criterion increase linearly | ||
+ | Simulation_Backup_Rate | ||
+ | Simulation_Checking_Rate | ||
+ | | ||
+ | | ||
+ | | ||
+ | | ||
+ | |||
+ | For more information on this data set, [[sunfluidh:simulation_management_setup_namelist|click here]]. | ||
+ | |||
+ | </note important> | ||
+ | Keep in mind the time step must be chosen with caution because it can generate numerical instabilities | ||
+ | | ||
+ | | ||
+ | When the time-step value is constant, the user can verify if the CFL criterion is respected by checking regularly the file checkcalc_xxxxx.d | ||
+ | |||
+ | </ |
sunfluidh/new_numerical_methods_setup_namelist.txt · Dernière modification : 2018/05/29 15:06 de witko