Time scheme descriptor. More...

#include <cs_parameters.h>

Collaboration diagram for cs_time_scheme_t:

Data Fields
int	time_order

int	isto2t

double	thetst

int	iccvfg

Detailed Description

Time scheme descriptor.

Members of the time scheme structure are publicly accessible, to allow for concise syntax, as they are expected to be used in many places.

Field Documentation

◆ iccvfg

iccvfg

indicates whether the dynamic field should be frozen or not:

1: true
0: false (default)
In such a case, the values of velocity, pressure and the variables related to the potential turbulence model ( , $R_{ij}$ , $\varepsilon$ , $\varphi$ , $\bar{f}$ , $\omega$ , turbulent viscosity) are kept constant over time and only the equations for the scalars are solved.
Also, if iccvfg = 1, the physical properties modified in cs_user_physical_properties will keep being updated. Beware of non-consistencies if these properties would normally affect the dynamic field (modification of density for instance).
Useful if and only if nscal 0 and the calculation is a restart.

◆ isto2t

isto2t

Specifies the time scheme activated for the source terms of the turbulence equations i.e. related to $k$ , $R_{ij}$ , $\varepsilon$ , $\omega$ , $\varphi$ , $\overline{f}$ ), apart from convection and diffusion.

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 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 thetst = 0.5)
2: the linear terms $S_i\phi$ are treated in the same isto2t = 1; the other terms are way as when extrapolated according to the same formula as when isto2t = 1, but with $\theta$ = thetst = 1.
Due to certain specific couplings between the turbulence equations, isto2t is allowed the value 1 or 2 only for the $R_{ij}$ models (iturb = 30 or 31); hence, it is always initialised to 0.

◆ thetst

thetst

$\theta$ -scheme for the extrapolation of the nonlinear explicit source terms $S_e$ of the turbulence equations when the source term extrapolation has been activated (see isto2t), following the formula $(S_e)^{n+\theta}=(1+\theta)S_e^n-\theta S_e^{n-1}$ .
The value of $theta$ is deduced from the value chosen for isto2t. Generally, only the value 0.5 is used.

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

◆ time_order

time_order

Global time order of time stepping

2: 2nd order
1: 1st order (default)

The documentation for this struct was generated from the following files: