Documentation du code de simulation numérique SUNFLUIDH

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Some examples illustrating how to use the relevant namelists to set the numerical methods for solving the equations

Some examples illustrating how to use the relevant namelists to set the numerical methods for solving the equations

Context : Heat driven incompressible flow

Numerical scheme for solving the governing equations of velocity and temperature
- Time discretization : semi-implicit formulation with the 2nd order Backward Differentiation formula (BDF2)
- Viscous and conduction fluxes (2nd order centered scheme selected by default with BDF2)
- convective flux for momentum equation : 2nd order centered scheme, conservative form
- advective flux for temperature equation : 2nd order centered scheme, conservative form
- Solving Poisson's equation : several examples

Example 1 : Solving the Poisson's equation by the partial diagonalization method

Only one namelist is required : “Numerical_Methods”. You first find the old version and then the new one. The both versions are strictly equivalent.
The old version :

    &Numerical_Methods  Numerical_Scheme= 1,
                        Convective_Flux_Discretization_Type            = 1 , 
                        Temperature_Advective_Flux_Discretization_Type = 1 ,  
                        Numerical_Method_Poisson_Equation   = 3    /

The corresponding new version :

  &Numerical_Methods  NS_NumericalMethod= "BDF2-SchemeO2",
                      MomentumConvection_Scheme="Centered-O2-Conservative" , 
                      TemperatureAdvection_Scheme="Centered-O2-Conservative" ,  
                      Poisson_NumericalMethod="Home-PartialDiagonalization"  /

Example 2 : Solving the Poisson's equation by an iterative method coupled with a multigrid procedure

                        
                        
                        
                        
                        
                        
                        
                        
                        
                     Iterative_Method_Selection         = 1    ,
                     Number_max_Grid= 4                         ,
                     Number_max_Cycle= 10                      ,
                     Number_Iteration= 15,
                     Number_Iteration_FineToCoarseGrid= 15,
                     Number_Iteration_CoarsestGrid= 15,
                     Number_Iteration_CoarseToFineGrid= 15,
                     Relaxation_Coefficient              = 1.80 , 
                     Convergence_Criterion = 1.D-08 /

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