Fluid properties descriptor. More...
#include <cs_physical_constants.h>
Data Fields | |
int | ixyzp0 |
int | icp |
int | icv |
int | irovar |
int | ivivar |
int | ivsuth |
double | ro0 |
double | viscl0 |
double | viscv0 |
double | p0 |
double | pred0 |
double | xyzp0 [3] |
double | t0 |
double | cp0 |
double | cv0 |
double | cpv0 |
double | cvl |
double | l00 |
double | lambda0 |
double | r_pg_cnst |
double | r_v_cnst |
double | rvsra |
double | clatev |
double | xmasmr |
int | ipthrm |
double | pther |
double | pthera |
double | pthermax |
double | sleak |
double | kleak |
double | roref |
Fluid properties descriptor.
Members of these fluid properties are publicly accessible, to allow for concise syntax, as they are expected to be used in many places.
clatev |
latent heat of evaporation
cp0 |
reference specific heat
Useful if cs_glob_thermal_model->itherm != CS_THERMAL_MODEL_NONE, unless the user specifies the specific heat in the user subroutine cs_user_physical_properties (icp > 0) with the compressible module or coal combustion, cp0 is also needed even when there is no user scalar.
cpv0 |
reference isobaric specific heat of water vapor (J/kg/K)
Useful for the moist air scheme
cv0 |
reference isochoric specific heat (J/kg/K)
Useful for the compressible module.
cvl |
reference specific heat for of liquid water (J/kg/K)
icp |
indicates if the isobaric specific heat is variable
icv |
property index of the isochoric specific heat
ipthrm |
uniform variable thermodynamic pressure:
irovar |
variable density field :
ivivar |
variable viscosity field :
ivsuth |
Sutherland law for laminar viscosity and thermal conductivity Only useful in gas mix (igmix) specific physics
ixyzp0 |
filling xyzp0 indicator
kleak |
Leak head loss (2.9 by default, from Idelcick)
l00 |
latent heat referenced at 273.15K (J/kg)
lambda0 |
reference heat conductivity (W/m/K)
Always useful. This was previously only available through the GUI, so in most cases, is set to 1.
p0 |
pred0 |
reference value for the reduced pressure (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 , 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.
pther |
Thermodynamic pressure for the current time step.
pthera |
thermodynamic pressure for the previous time step
pthermax |
thermodynamic maximum pressure for user clipping, used to model a venting effect
r_pg_cnst |
Perfect Gas specific constant in J/kg/K
This value depends on the gas since it is equal to R/M where R is the universal gas constant and M is the molar mass
r_v_cnst |
Water vapor gas constant in J/kg/K
Useful when performing humid air simulations
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 and
). 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 cs_user_physical_properties. Indeed, except with the compressible module, CS does not use the total pressure when solving the Navier-Stokes equation, but a reduced pressure
, where
is a reference point (see xyzp0) and
and
are reference values (see pred0 and p0). Hence, the term
in the equation is treated as
. The closer ro0 is to the value of
, the more
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
and
appear in the log and the post-processing outputs with the compressible module, the calculation is made directly on the total pressure.
roref |
Initial reference density
rvsra |
ratio gas constant h2o / dry air
sleak |
Leak surface
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.
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 cs_user_physical_properties.
viscv0 |
reference volume viscosity
Noted in the equation expressing
in the paragraph dedicated to iviscv)
Used by the compressible model, unless the user specifies a variable volume viscosity in the GUI or cs_user_physical_properties.
xmasmr |
molar mass of the perfect gas in (if ieos=1)
Always useful.
xyzp0[3] |
coordinates of the reference point for the total pressure
Always useful, except with the compressible module.