8.0
general documentation
Variables
Field keywords

Variables

char * label
 
int coupled
 
int moment_id
 
int time_extrapolated
 
int limiter_choice
 
int scalar_id
 
cs_equation_param_t * var_cal_opt
 
cs_solving_info_t * solving_info
 
char * restart_file
 
int diffusivity_id
 
double diffusivity_ref
 
int density_id
 
double turbulent_flux_ctheta
 
double turbulent_flux_model
 
int first_moment_id
 
int variance_clipping
 
double variance_dissipation
 
int scalar_diffusivity_prev
 
int scalar_time_scheme
 
double st_exp_extrapolated
 
double diffusivity_extrapolated
 
double time_step_factor
 

Detailed Description

Variable Documentation

◆ coupled

coupled

If > 0, this variable is coupled using the internal coupling mechanism.

Restricted to fields with CS_FIELD_VARIABLE type.

◆ density_id

density_id

Field id of the matching density for a scalar when defined as variable and different from the bulk. This must be consistent with continuity equation, and is used for fluid-solid computations with passive scalars with a different density in the solid.

Negative value if the field has constant density.

If set to 0, a matching field will be created and its value reset automatically to that field's id. If set directly to a value > 0, it is assumed that the matching density field has already been defined and is associated with this scalar. This allows both creating an associated field automatically or in more advanced cases, sharing a density field between several scalars.

◆ diffusivity_extrapolated

diffusivity_extrapolated

$ \theta $-scheme for the extrapolation of the physical property $\phi$ "diffusivity" when the extrapolation has been activated (see time_extrapolated key word), according to the formula $\phi^{n+\theta}=(1+\theta)\phi^n-\theta \phi^{n-1}$.
The value of $\theta$ = thetvs is deduced from the value chosen for time_extrapolated key word. Generally, only the value 0.5 is used.

  • 0: explicit
  • 1/2: extrapolated in n+1/2
  • 1: extrapolated in n+1

◆ diffusivity_id

diffusivity_id

Field id of the matching molecular diffusivity for a scalar. Negative value if the field has constant diffusivity.

If set to 0, a matching field will be created and its value reset automatically to that field's id. If set directly to a value > 0, it is assumed that the matching diffusivity field has already been defined and is associated with this scalar. This allows both creating an associated field automatically or in more advanced cases, sharing a diffusivity field between several scalars.

◆ diffusivity_ref

diffusivity_ref

Reference molecular diffusivity for a scalar ( $kg.m^{-1}.s^{-1}$). Negative value if not initialized or used.

Warning
: for a temperature, the diffusivity is defined as $\lambda/C_p$ where $\lambda$ and $C_p$ are the conductivity and specific heat. When using the Graphical Interface, $\lambda$ and $C_p$ are specified separately, and the matching molecular diffusivity is computed automatically.
With the compressible module, diffusivity_ref (given in uscfx2) is directly the thermal conductivity $W.m^{-1}.K^{-1}$.
With gas or coal combustion, the molecular diffusivity of the enthalpy ( $kg.m^{-1}.s^{-1}$) must be specified by the user in the variable ppthch::diftl0 "diftl0"(cs_user_combustion).
With the electric module, for the Joule effect, the diffusivity is specified by the user in cs_user_physical_properties.c (even if it is constant). For the electric arcs, it is calculated from the thermochemical data file.

◆ first_moment_id

first_moment_id

For a variance of a given field, id of the base (first moment) field.

◆ label

label

Optional label associated to the field; if NULL, name will be used instead.

◆ limiter_choice

limiter_choice

Integer corresponding to the type of Roe-Sweby Limiter:

  • 1: minmod
  • 2: Van-Leer
  • 3: Van-Albada
  • 4: superbee

Restricted to fields with CS_FIELD_VARIABLE type.

◆ moment_id

moment_id

If > -1, refers to the field if of which the current field is a time moment (see cs_time_moment.h). If < 0, the current field is not a time moment.

Restricted to fields with both CS_FIELD_VARIABLE and CS_FIELD_POSTPROCESS type.

◆ restart_file

restart_file

Indicates in which restart file the associated info may be found.

If NULL, default rules apply.

◆ scalar_diffusivity_prev

int scalar_diffusivity_prev

◆ scalar_id

scalar_id

Matching scalar id (inverse Fortran isca(iscal) ), or -1 if the field does not represent a solved scalar type variable.

◆ scalar_time_scheme

scalar_time_scheme

For each scalar, specifies the time scheme activated for the source terms of the equation for the scalar, apart from convection and diffusion (for instance: variance production, user-specified terms, ...).

  • 0: "standard" first-order: the terms which are linear functions of the solved variable are implicit and the others are explicit
  • 1: second-order: the terms of the form $S_i\phi$ which are linear functions of the solved variable $\phi$ are expressed as second-order terms by interpolation (according to the formula $(S_i\phi)^{n+\theta}=S_i^n[(1-\theta)\phi^n+\theta\phi^{n+1}]$, $\theta$ being given by the value of thetav associated with the variable $\phi$); the other terms $S_e$ are expressed as second-order terms by extrapolation (according to the formula $(S_e)^{n+\theta}=[(1+\theta)S_e^n-\theta S_e^{n-1}]$, $\theta$ being given by the value of st_exp_extrapolated = 0.5)
  • 2: the linear terms $S_i\phi$ are treated in the same way as when scalar_time_scheme = 1; the other terms $S_e$ are extrapolated according to the same formula as when scalar_time_scheme = 1, but with $\theta$ = st_exp_extrapolated = 1.
    By default, scalar_time_scheme is initialised to 1 (second-order) when the selected time scheme is second-order (ischtp = 2), otherwise to 0.

◆ solving_info

solving_info

Structure containing the solving info of the field variables (used for log, not setup, so set NULL setup logging function)

Restricted to fields with CS_FIELD_VARIABLE type.

◆ st_exp_extrapolated

st_exp_extrapolated

$ \theta $-scheme for the extrapolation of the nonlinear explicit source term $S_e$ of the scalar transport equation when the source term extrapolation has been activated (see scalar_time_scheme), following the formula $(S_e)^{n+\theta}=(1+\theta)S_e^n-\theta S_e^{n-1}$.
The value of $\theta$ = thetss is deduced from the value chosen for scalar_time_scheme. Generally, only the value 0.5 is used.

  • 0: explicit
  • 1/2: extrapolated in n+1/2
  • 1: extrapolated in n+1

◆ time_extrapolated

time_extrapolated

Is the field time-extrapolated?

  • -1: default automatic value
  • 0: "standard" first-order: the value calculated at the beginning of the current time step (from the variables known at the end of the previous time step) is used
  • 1: second-order: the physical property $\phi$ is extrapolated according to the formula $\phi^{n+\theta}=[(1+\theta)\phi^n-\theta \phi^{n-1}]$, $\theta$ being given by the value of 0.5
  • 2: first-order: the physical property $\phi$ is extrapolated at $n+1$ according to the same formula as when = 1 but with $\theta$ = 1

◆ time_step_factor

time_step_factor

Multiplicator coefficient for the time step of each variable

  • unused for vel, p
  • for k, epsilon the same value is taken (value of k)
  • for Rij, epsilon the same value is taken (value of Rij[xx])
    Hence, the time step used when solving the evolution equation for the variable is the time step used for the dynamic equations (velocity/pressure) multiplied by time_step_factor. Yet, the value of time_step_factor for the velocity components and the pressure is not used. Also, although it is possible to change the value of time_step_factor for the turbulent variables, it is highly discouraged.

◆ turbulent_flux_ctheta

turbulent_flux_ctheta

Coefficient of GGDH and AFM turbulent flux models.

◆ turbulent_flux_model

turbulent_flux_model

Turbulent flux model

  • 0: Simple Gradient Diffusion Hypothesis (SGDH)
  • 10: Generalized Gradient Diffusion Hypothesis (GGDH)
  • 11: Generalized Gradient Diffusion Hypothesis with Elliptic Blending (EB-GGDH)
  • 20: Algebraic Flux Model (AFM)
  • 21: Algebraic Flux Model with Elliptic Blending (EB-AFM)
  • 30: Differential Flux Model (DFM)
  • 31: Differential Flux Model with Elliptic Blending (EB-DFM)

◆ var_cal_opt

var_cal_opt

Structure containing the equation parameters of a solved variable.

Restricted to fields with CS_FIELD_VARIABLE type.

◆ variance_clipping

variance_clipping

For every scalar representing the average of the square of the fluctuations of another scalar (noted $f$), indicator of the clipping method:

  • -1: no clipping because the scalar does not represent the average of the square of the fluctuations of another scalar.
  • 0: clipping to 0 for the lower range of values.
  • 1: clipping to 0 for the lower range of values and to $(f-f_{min})(f_{max}-f)$ for higher values, where $f$ is the associated scalar, $f_{min}$ and $f_{max}$ its minimum and maximum values specified by the user (i.e. min_scalar_clipping and max_scalar_clipping).
  • 2: clipping to max(0, min_scalar_clipping) for lower values and to max_scalar_clipping for higher values.scamin and scamax are limits specified by the user.
    Useful for the scalar with a variance.

◆ variance_dissipation

variance_dissipation

Represents the coefficient $R_f$ in the dissipation term $-\frac{\rho}{R_f}\frac{\varepsilon}{k}$ of the equation concerning the scalar, which represents the mean square root of the fluctuations of the scalar.