programmer's documentation
Modules | Variables
Module for physical constants
Collaboration diagram for Module for physical constants:

Modules

 Module for turbulence constants
 

Variables

double precision tkelvi
 Temperature in Kelvin correponding to 0 degrees Celsius (= +273,15) More...
 
double precision tkelvn
 Temperature in degrees Celsius corresponding to 0 Kelvin (= -273,15) More...
 
double precision xcal2j
 Calories (1 cvar_al = xcal2j J) More...
 
double precision stephn
 Stephan constant for the radiative module $\sigma$ in $W.m^{-2}.K^{-4}$. More...
 
double precision rair
 Perfect gas constant for air (mixture) More...
 
real(c_double), pointer, save cs_physical_constants_r
 Perfect gas constant in $J/mol/K$. More...
 
real(c_double), pointer, save gx
 Gravity. More...
 
real(c_double), pointer, save gy
 
real(c_double), pointer, save gz
 
integer(c_int), pointer, save icorio
 Coriolis effects. More...
 
integer(c_int), pointer, save ixyzp0
 Physical constants of the fluid filling xyzp0 indicator. More...
 
integer(c_int), pointer, save ieos
 indicates the equation of state for compressible module. Only perfect gas with a constant adiabatic coefficient, ieos=1 is available, but the user can complete the file cs_cf_thermo.h, which is not a user source, to add new equations of state. More...
 
integer(c_int), pointer, save icp
 isobaric specific heat $ C_p $ More...
 
integer(c_int), pointer, save icv
 isochoric specific heat $ C_v $ More...
 
integer(c_int), pointer, save irovar
 variable density field $ \rho $: More...
 
integer(c_int), pointer, save ivivar
 variable viscosity field $ \mu $: More...
 
integer(c_int), pointer, save ivsuth
 Sutherland law for laminar viscosity and thermal conductivity Only useful in gas mix (igmix) specific physics. More...
 
real(c_double), pointer, save ro0
 reference density. Negative value: not initialized. Its value is not used in gas or coal combustion modelling (it will be calculated following the perfect gas law, with $P0$ and $T0$). With the compressible module, it is also not used by the code, but it may be (and often is) referenced by the user in user subroutines; it is therefore better to specify its value. More...
 
real(c_double), pointer, save viscl0
 reference molecular dynamic viscosity. Negative value: not initialized. More...
 
real(c_double), pointer, save p0
 reference pressure for the total pressure. except with the compressible module, the total pressure $P$ is evaluated from the reduced pressure $P^*$ so that $P$ is equal to p0 at the reference position $\vect{x}_0$ (given by xyzp0). with the compressible module, the total pressure is solved directly. always Useful More...
 
real(c_double), pointer, save pred0
 reference value for the reduced pressure $P^*$ (see ro0). It is especially used to initialise the reduced pressure and as a reference value for the outlet boundary conditions. For an optimised precision in the resolution of $P^*$, it is wiser to keep pred0 to 0. With the compressible module, the "pressure" variable appearing in the equations directly represents the total pressure. It is therefore initialized to p0 and not pred0 (see ro0). Always useful, except with the compressible module More...
 
real(c_double), dimension(:), pointer, save xyzp0
 coordinates of the reference point $\vect{x}_0$ for the total pressure. More...
 
real(c_double), pointer, save t0
 reference temperature. More...
 
real(c_double), pointer, save cp0
 reference specific heat. More...
 
real(c_double), pointer, save cv0
 Reference isochoric specific heat. More...
 
real(c_double), pointer, save psginf
 Stiffened gas (ieos=2) limit pressure (Pa) Equal to zero in perfect gas. More...
 
real(c_double), pointer, save gammasg
 Stiffened gas (ieos=2) polytropic coefficient (dimensionless) More...
 
real(c_double), pointer, save xmasmr
 Molar mass of the perfect gas in $ kg/mol $ (if ieos=1) More...
 
real(c_double), pointer, save pther
 Uniform thermodynamic pressure for the low-Mach algorithm Thermodynamic pressure for the current time step. More...
 
real(c_double), pointer, save pthera
 Thermodynamic pressure for the previous time step. More...
 
real(c_double), pointer, save pthermax
 pthermax: Thermodynamic maximum pressure for user clipping, used to model a venting effect More...
 

Detailed Description

Variable Documentation

real(c_double), pointer, save cp0

reference specific heat.

Useful if there is 1 <= n <= nscaus, so that iscalt = n and itherm = 1 (there is a "temperature" scalar), unless the user specifies the specific heat in the user subroutine usphyv (icp > 0) with the compressible module or coal combustion, cp0 is also needed even when there is no user scalar.

Note
None of the scalars from the specific physics is a temperature.
When using the Graphical Interface, cp0 is also used to calculate the diffusivity of the thermal scalars, based on their conductivity; it is therefore needed, unless the diffusivity is also specified in usphyv.
real(c_double), pointer, save cs_physical_constants_r

Perfect gas constant in $J/mol/K$.

real(c_double), pointer, save cv0

Reference isochoric specific heat.

Useful for the compressible module (J/kg/K)

real(c_double), pointer, save gammasg

Stiffened gas (ieos=2) polytropic coefficient (dimensionless)

real(c_double), pointer, save gx

Gravity.

real(c_double), pointer, save gy
real(c_double), pointer, save gz
integer(c_int), pointer, save icorio

Coriolis effects.

integer(c_int), pointer, save icp

isobaric specific heat $ C_p $

integer(c_int), pointer, save icv

isochoric specific heat $ C_v $

integer(c_int), pointer, save ieos

indicates the equation of state for compressible module. Only perfect gas with a constant adiabatic coefficient, ieos=1 is available, but the user can complete the file cs_cf_thermo.h, which is not a user source, to add new equations of state.

integer(c_int), pointer, save irovar

variable density field $ \rho $:

  • 1: true
  • 0: false
integer(c_int), pointer, save ivivar

variable viscosity field $ \mu $:

  • 1: true
  • 0: false
integer(c_int), pointer, save ivsuth

Sutherland law for laminar viscosity and thermal conductivity Only useful in gas mix (igmix) specific physics.

  • 1: Sutherland law
  • 0: low temperature law (linear except for helium)
integer(c_int), pointer, save ixyzp0

Physical constants of the fluid filling xyzp0 indicator.

real(c_double), pointer, save p0

reference pressure for the total pressure. except with the compressible module, the total pressure $P$ is evaluated from the reduced pressure $P^*$ so that $P$ is equal to p0 at the reference position $\vect{x}_0$ (given by xyzp0). with the compressible module, the total pressure is solved directly. always Useful

real(c_double), pointer, save pred0

reference value for the reduced pressure $P^*$ (see ro0). It is especially used to initialise the reduced pressure and as a reference value for the outlet boundary conditions. For an optimised precision in the resolution of $P^*$, it is wiser to keep pred0 to 0. With the compressible module, the "pressure" variable appearing in the equations directly represents the total pressure. It is therefore initialized to p0 and not pred0 (see ro0). Always useful, except with the compressible module

real(c_double), pointer, save psginf

Stiffened gas (ieos=2) limit pressure (Pa) Equal to zero in perfect gas.

real(c_double), pointer, save pther

Uniform thermodynamic pressure for the low-Mach algorithm Thermodynamic pressure for the current time step.

real(c_double), pointer, save pthera

Thermodynamic pressure for the previous time step.

real(c_double), pointer, save pthermax

pthermax: Thermodynamic maximum pressure for user clipping, used to model a venting effect

double precision rair

Perfect gas constant for air (mixture)

real(c_double), pointer, save ro0

reference density. Negative value: not initialized. Its value is not used in gas or coal combustion modelling (it will be calculated following the perfect gas law, with $P0$ and $T0$). With the compressible module, it is also not used by the code, but it may be (and often is) referenced by the user in user subroutines; it is therefore better to specify its value.

Always useful otherwise, even if a law defining the density is given by the user subroutines usphyv or uselph. indeed, except with the compressible module, CS does not use the total pressure $P$ when solving the Navier-Stokes equation, but a reduced pressure . $P^*=P-\rho_0\vect{g}.(\vect{x}-\vect{x}_0)+P^*_0-P_0$. where $\vect{x_0}$ is a reference point (see xyzp0) and $P^*_0$ and $P_0$ are reference values (see pred0 and p0). Hence, the term $-\grad{P}+\rho\vect{g}$ in the equation is treated as $-\grad{P^*}+(\rho-\rho_0)\vect{g}$. The closer ro0 is to the value of $\rho$, the more $P^*$ will tend to represent only the dynamic part of the pressure and the faster and more precise its solution will be. Whatever the value of ro0, both $P$ and $P^*$ appear in the listing and the post-processing outputs.. with the compressible module, the calculation is made directly on the total pressure

double precision stephn

Stephan constant for the radiative module $\sigma$ in $W.m^{-2}.K^{-4}$.

real(c_double), pointer, save t0

reference temperature.

Useful for the specific physics gas or coal combustion (initialization of the density), for the electricity modules to initialize the domain temperature and for the compressible module (initializations). It must be given in Kelvin.

double precision tkelvi

Temperature in Kelvin correponding to 0 degrees Celsius (= +273,15)

double precision tkelvn

Temperature in degrees Celsius corresponding to 0 Kelvin (= -273,15)

real(c_double), pointer, save viscl0

reference molecular dynamic viscosity. Negative value: not initialized.

Always useful, it is the used value unless the user specifies the viscosity in the subroutine usphyv

double precision xcal2j

Calories (1 cvar_al = xcal2j J)

real(c_double), pointer, save xmasmr

Molar mass of the perfect gas in $ kg/mol $ (if ieos=1)

Always useful

real(c_double), dimension(:), pointer, save xyzp0

coordinates of the reference point $\vect{x}_0$ for the total pressure.

  • When there are no Dirichlet conditions for the pressure (closed domain), xyzp0 does not need to be specified (unless the total pressure has a clear physical meaning in the configuration treated).
  • When Dirichlet conditions on the pressure are specified but only through stantard outlet conditions (as it is in most configurations), xyzp0 does not need to be specified by the user, since it will be set to the coordinates of the reference outlet face (i.e. the code will automatically select a reference outlet boundary face and set xyzp0 so that $P$ equals p0 at this face). Nonetheless, if xyzp0 is specified by the user, the calculation will remain correct.
  • When direct Dirichlet conditions are specified by the user (specific value set on specific boundary faces), it is better to specify the corresponding reference point (i.e. specify where the total pressure is p0). This way, the boundary conditions for the reduced pressure will be close to pred0, ensuring an optimal precision in the resolution. If xyzp0 is not specified, the reduced pressure will be shifted, but the calculations will remain correct..
  • With the compressible module, the "pressure" variable appearing in the equations directly represents the total pressure. xyzp0 is therefore not used..

Always useful, except with the compressible module.