Equation Specification¶

CGNS Mid-Level Library - Equation Specification

Equation Specification

Flow Equation Set
- cg_equationset_write - Write dimensionality of flow equations
- cg_equationset_read - Read flow equation set info
- cg_equationset_chemistry_read - Read chemistry equation set info
- cg_equationset_elecmagn_read - Read electromagnetic equation set info
Governing Equations
- cg_governing_write - Write type of governing equation
- cg_governing_read - Read type of governing equation
- cg_diffusion_write - Write flags for diffusion terms
- cg_diffusion_read - Read flags for diffusion terms
Auxiliary Models
- cg_model_write - Write auxiliary model types
- cg_model_read - Read auxiliary model types

Flow Equation Set

Node: FlowEquationSet_t (SIDS, File Mapping)

Functions	Modes
`ier = cg_equationset_write(int EquationDimension);`	`- w m`
`ier = cg_equationset_read(int EquationDimension, int GoverningEquationsFlag, int GasModelFlag, int ViscosityModelFlag, int ThermalConductModelFlag, int TurbulenceClosureFlag, int *TurbulenceModelFlag);`	`r - m`
`ier = cg_equationset_chemistry_read(int ThermalRelaxationFlag, int ChemicalKineticsFlag);`	`r - m`
`ier = cg_equationset_elecmagn_read(int ElecFldModelFlag, int MagnFldModelFlag, int *ConductivityModelFlag);`	`r - m`
`call cg_equationset_write_f(EquationDimension, ier)`	`- w m`
`call cg_equationset_read_f(EquationDimension, GoverningEquationsFlag, GasModelFlag, ViscosityModelFlag, ThermalConductModelFlag, TurbulenceClosureFlag, TurbulenceModelFlag, ier)`	`r - m`
`call cg_equationset_chemistry_read_f(ThermalRelaxationFlag, ChemicalKineticsFlag, ier)`	`r - m`
`call cg_equationset_elecmagn_read_f(ElecFldModelFlag, MagnFldModelFlag, ConductivityModelFlag, ier)`	`r - m`

Input/Output

	`EquationDimension`		Dimensionality of the governing equations; it is the number of spatial variables describing the flow.
	`GoverningEquationsFlag`		Flag indicating whether or not this `FlowEquationSet_t` node includes the definition of the governing equations; 0 if it doesn't, 1 if it does.
	`GasModelFlag`		Flag indicating whether or not this `FlowEquationSet_t` node includes the definition of a gas model; 0 if it doesn't, 1 if it does.
	`ViscosityModelFlag`		Flag indicating whether or not this `FlowEquationSet_t` node includes the definition of a viscosity model; 0 if it doesn't, 1 if it does.
	`ThermalConductModelFlag`		Flag indicating whether or not this `FlowEquationSet_t` node includes the definition of a thermal conductivity model; 0 if it doesn't, 1 if it does.
	`TurbulenceClosureFlag`		Flag indicating whether or not this `FlowEquationSet_t` node includes the definition of the turbulence closure; 0 if it doesn't, 1 if it does.
	`TurbulenceModelFlag`		Flag indicating whether or not this `FlowEquationSet_t` node includes the definition of a turbulence model; 0 if it doesn't, 1 if it does.
	`ThermalRelaxationFlag`		Flag indicating whether or not this `FlowEquationSet_t` node includes the definition of a thermal relaxation model; 0 if it doesn't, 1 if it does.
	`ChemicalKineticsFlag`		Flag indicating whether or not this `FlowEquationSet_t` node includes the definition of a chemical kinetics model; 0 if it doesn't, 1 if it does.
	`ElecFldModelFlag`		Flag indicating whether or not this `FlowEquationSet_t` node includes the definition of an electric field model for electromagnetic flows;; 0 if it doesn't, 1 if it does.
	`MagnFldModelFlag`		Flag indicating whether or not this `FlowEquationSet_t` node includes the definition of a magnetic field model for electromagnetic flows;; 0 if it doesn't, 1 if it does.
	`ConductivityModelFlag`		Flag indicating whether or not this `FlowEquationSet_t` node includes the definition of a conductivity model for electromagnetic flows; 0 if it doesn't, 1 if it does.
	`ier`		Error status.

Governing Equations

Node: GoverningEquations_t (SIDS, File Mapping)

Functions	Modes
`ier = cg_governing_write(GoverningEquationsType_t Equationstype);`	`- w m`
`ier = cg_governing_read(GoverningEquationsType_t *EquationsType);`	`r - m`
`ier = cg_diffusion_write(int *diffusion_model);`	`- w m`
`ier = cg_diffusion_read(int *diffusion_model);`	`r - m`
`call cg_governing_write_f(EquationsType, ier)`	`- w m`
`call cg_governing_read_f(EquationsType, ier)`	`r - m`
`call cg_diffusion_write_f(diffusion_model, ier)`	`- w m`
`call cg_diffusion_read_f(diffusion_model, ier)`	`r - m`

Input/Output

	`EquationsType`		Type of governing equations. The admissible types are `CG_Null`, `CG_UserDefined`, `FullPotential`, `Euler`, `NSLaminar`, `NSTurbulent`, `NSLaminarIncompressible`, and `NSTurbulentIncompressible`.
	`diffusion_model`		Flags defining which diffusion terms are included in the governing equations. This is only applicable to the Navier-Stokes equations with structured grids. See the discussion in the SIDS manual for details.
	`ier`		Error status.

Auxiliary Models

Nodes: GasModel_t (SIDS, File Mapping)
ViscosityModel_t (SIDS, File Mapping)
ThermalConductivityModel_t (SIDS, File Mapping)
TurbulenceClosure_t (SIDS, File Mapping)
TurbulenceModel_t (SIDS, File Mapping)
ThermalRelaxationModel_t (SIDS, File Mapping)
ChemicalKineticsModel_t (SIDS, File Mapping)
EMElectricFieldModel_t (SIDS, File Mapping)
EMMagneticFieldModel_t (SIDS, File Mapping)
EMConductivityModel_t (SIDS, File Mapping)

Functions	Modes
`ier = cg_model_write(char *ModelLabel, ModelType_t ModelType);`	`- w m`
`ier = cg_model_read(char ModelLabel, ModelType_t ModelType);`	`r - m`
`call cg_model_write_f(ModelLabel, ModelType, ier)`	`- w m`
`call cg_model_read_f(ModelLabel, ModelType, ier)`	`r - m`

Input/Output

	`ModelLabel`		The CGNS label for the model being defined. The models supported by CGNS are: `GasModel_t` `ViscosityModel_t` `ThermalConductivityModel_t` `TurbulenceClosure_t` `TurbulenceModel_t` `ThermalRelaxationModel_t` `ChemicalKineticsModel_t` `EMElectricFieldModel_t` `EMMagneticFieldModel_t` `EMConductivityModel_t`

	`ModelType`		One of the model types (listed below) allowed for the `ModelLabel` selected.
	`ier`		Error status.

The types allowed for the various models are:

	`GasModel_t`		`CG_Null, CG_UserDefined, Ideal, VanderWaals, CaloricallyPerfect, ThermallyPerfect, ConstantDensity, RedlichKwong`
	`ViscosityModel_t`		`CG_Null, CG_UserDefined, Constant, PowerLaw, SutherlandLaw`
	`ThermalConductivityModel_t`		`CG_Null, CG_UserDefined, PowerLaw, SutherlandLaw, ConstantPrandtl`
	`TurbulenceModel_t`		`CG_Null, CG_UserDefined, Algebraic_BaldwinLomax, Algebraic_CebeciSmith, HalfEquation_JohnsonKing, OneEquation_BaldwinBarth, OneEquation_SpalartAllmaras, TwoEquation_JonesLaunder, TwoEquation_MenterSST, TwoEquation_Wilcox`
	`TurbulenceClosure_t`		`CG_Null, CG_UserDefined, EddyViscosity, ReynoldsStress, ReynoldsStressAlgebraic`
	`ThermalRelaxationModel_t`		`CG_Null, CG_UserDefined, Frozen, ThermalEquilib, ThermalNonequilib`
	`ChemicalKineticsModel_t`		`CG_Null, CG_UserDefined, Frozen, ChemicalEquilibCurveFit, ChemicalEquilibMinimization, ChemicalNonequilib`
	`EMElectricFieldModel_t`		`CG_Null, CG_UserDefined, Constant, Frozen, Interpolated, Voltage`
	`EMMagneticFieldModel_t`		`CG_Null, CG_UserDefined, Constant, Frozen, Interpolated`
	`EMConductivityModel_t`		`CG_Null, CG_UserDefined, Constant, Frozen, Equilibrium_LinRessler, Chemistry_LinRessler`