Variables and properties can be accessed both in Fortran and in C using the cs_field API.

Accessing variables and properties in Fortran:

Both variables and properties can be accessed via the cs_field API, using the global field indices and indirections arrays, as in the following examples:
- For one-dimensional arrays :
  
  call field_get_val_s(ivarfl(ipr), cvar_pr) pres = cvar_pr(iel),
  
  call field_get_val_s(icp, cpro_cp) cp = cpro_cp(iel)
  
  The values of scalar variable can be accessed as follows:
  
  call field_get_val_s(ivarfl(isca(iscalt)), cvar_scalt) temp = cvar_scalt(iel)
- For interleaved multidimensional arrays:
  
  call field_get_val_v(ivarfl(iu), cvar_vel) ux = cvar_vel(1,iel)
ipr, iu are here variable indices and the array ivarfl allows to get the corresponding field indices.
isca(iscalt) is also a variable index (iscalt is the scalar index of the thermal scalar).
icp is directly a field index (there is no equivalent to the array ivarfl for field of type properties).
Alternatively, if no global index is pointing to the searched field, variables and properties can be accessed using their field names:
- For one-dimensional arrays :
  
  call field_get_val_s_by_name("pressure", cvar_pr) pres = cvar_pr(iel)

Accessing variables and properties in C:

Almost all variables and properties can be accessed using the CS_F_ macro:
- For one-dimensional arrays :
  
  press = CS_F_(p)->val[cell_id],
  
  cp = CS_F_(cp)->val[cell_id]
  
  temp = CS_F_(t)->val[cell_id]
- For multidimensional arrays:
  
  uz = CS_F_(vel)->val[3*cell_id + 2]
  
  These arrays can also be casted as follows (for a 3-D array):
  
  cs_real_3_t *cvar_vel = (cs_real_3_t *)CS_F_(vel)->val
  
  The cell value can then be accessed as :
  
  ux = cvar_vel[cell_id][0]
vel, p, or cp are defined in cs_field_pointer.h.
Indexed variables (such as user scalars) and indexed properties are accessed as:
CS_FI_(name,ii-1)->val[cell_id].
In any case, all variables can be accessed using the function cs_field_by_name :
cs_real_t *cvar_pr = cs_field_by_name("pressure")->val

Remarks: Note that indexes in C begin at 0, while indexes in Fortran begin at 1. Thus, Fortran and C loop counters are related in the following as:
cell_id = iel-1.

Cross-reference tables are available for the variables and properties of the standard solver and the specific physics features:

Variables

The Fortran variables indexes are defined in the files numvar.f90 (with the exception of ihm and iscal, which are respectively defined in ppincl.f90 and optcal.f90) and the C variables names are defined in cs_field_pointer.h.
Note that dt is just an allocatable array in Fortran while it is mapped as a field in C.

Fortran code	C code	Description
call field_get_val_s(ivarfl(ipr), cvar_pr)	CS_F_(p)->val	Pressure
call field_get_val_v(ivarfl(iu), cvar_vel)	CS_F_(vel)->val	Velocity
call field_get_val_s(ivarfl(ivoidf), cvar_voidf)	CS_F_(void_f)->val	Void fraction for Volume of Fluid model
call field_get_val_s(ivarfl(ik ), cvar_k )	CS_F_(k)->val	Turbulent kinetic energy
call field_get_val_s(ivarfl(iep ), cvar_eps)	CS_F_(eps)->val	Turbulent dissipation $\varepsilon$
call field_get_val_s(ivarfl(ir11), cvar_r11)	CS_F_(r11)->val	Reynolds stress component $R_{xx}$
call field_get_val_s(ivarfl(ir22), cvar_r22)	CS_F_(r22)->val	Reynolds stress component $R_{yy}$
call field_get_val_s(ivarfl(ir33), cvar_r33)	CS_F_(r33)->val	Reynolds stress component $R_{zz}$
call field_get_val_s(ivarfl(ir12), cvar_r12)	CS_F_(r12)->val	Reynolds stress component $R_{xy}$
call field_get_val_s(ivarfl(ir23), cvar_r23)	CS_F_(r23)->val	Reynolds stress component $R_{yz}$
call field_get_val_s(ivarfl(ir13), cvar_r13)	CS_F_(r13)->val	Reynolds stress component $R_{xz}$
call field_get_val_s(ivarfl(iphi), cvar_phi)	CS_F_(phi)->val	$\phi$ for $\phi-f_b$ model
call field_get_val_s(ivarfl(ifb ), cvar_fb )	CS_F_(f_bar)->val	for $\phi-f_b$ model
call field_get_val_s(ivarfl(ial ), cvar_al )	CS_F_(alp_bl)->val	$\alpha$ for or EBRSM model
call field_get_val_s(ivarfl(iomg), cvar_omg)	CS_F_(omg)->val	$\omega$ for $k-\omega$ SST model
call field_get_val_s(ivarfl(inusa), cvar_nusa)	CS_F_(nusa)->val	$\widetilde{\nu}_T$ for Spalart-Allmaras
call field_get_val_v(ivarfl(iuma), cvar_mesh_v)	CS_F_(mesh_u)->val	Mesh velocity
call field_get_val_s(ivarfl(isca(ihm)), cvar_hm)	CS_F_(h)->val	Enthalpy
call field_get_val_s(ivarfl(isca(iscalt)), cvar_scalt)	CS_F_(t)->val	Temperature

Properties

These properties are defined in the files numvar.f90 and cs_field_pointer.h.

Fortran code	C code	Description
dt	CS_F_(dt)->val	Local time step
call field_get_val_s(iviscl, cpro_viscl)	CS_F_(mu)->val	Molecular viscosity
call field_get_val_s(ivisct, cpro_visct)	CS_F_(mu_t)->val	Turbulent dynamic viscosity
call field_get_val_s(icp, cpro_cp)	CS_F_(cp)->val	Specific heat
call field_get_val_s(icrom, cpro_crom)	CS_F_(rho)->val	Density (at cells)
call field_get_val_s(ibrom, bpro_rho)	CS_F_(rho_b)->val[face_id]	Density (at boundary faces)
call field_get_val_s(ismago, cpro_smago)	cs_real_t *cpro_smago = cs_field_by_name("smagorinsky_constant^2")->val	Field id of the anisotropic turbulent viscosity
call field_get_val_s(icour, cpro_cour)	cs_real_t *cpro_cour = cs_field_by_name("courant_number")->val	Courant number
call field_get_val_s(ifour, cpro_four)	cs_real_t *cpro_four = cs_field_by_name("fourier_number")->val	Fourier number
call field_get_val_s(iprtot, cpro_prtot)	cs_real_t *cpro_prtot = cs_field_by_name("total_pressure")->val	Total pressure at cell centers
call field_get_val_s(ivisma, cpro_visma_s)	cs_real_t *cpro_visma_s = cs_field_by_name("mesh_viscosity")->val	Mesh velocity viscosity (scalar) for the ALE module
call field_get_val_v(ivisma, cpro_visma_s)	cs_real_t *cpro_visma_v = cs_field_by_name("mesh_viscosity")->val	Mesh velocity viscosity (vector) for the ALE module
call field_get_val_s(itsrho), cpro_tsrho )	cs_real_t *cpro_tsrho = cs_field_by_name("dila_st")->val	Global dilatation source terms
call field_get_val_s(ibeta), cpro_beta )	cs_real_t *cpro_beta = cs_field_by_name("thermal_expansion")->val	Thermal expansion coefficient
call field_get_val_s(ipori, cpro_ipori)	CS_F_(poro)->val	Porosity
call field_get_val_v(iporf, cpro_iporf)	CS_F_(t_poro)->val	Tensorial porosity
call field_get_val_v(iforbr, bpro_forbr)	cs_real_t *bpro_forbr = cs_field_by_name("boundary_forces")->val	Field id of the stresses at boundary
call field_get_val_s(iyplbr, bpro_yplus)	cs_real_t *bpro_yplus = cs_field_by_name("yplus")->val	Field id of at boundary
call field_get_val_v(idtten, dttens)	cs_real_t *dttens = cs_field_by_name("dttens")->val	Field id for the dttens tensor
call field_get_val_s(itempb, t_b)	CS_F_(t_b)->val	Boundary temperature

Specific physics

Atmospheric

Defined in optcal.f90, atincl.f90, atvarp.f90 and cs_field_pointer.h.

Fortran code	C code	Description
`call field_get_val_s(ivarfl(isca(iscalt)), cvar_scalt)`	`CS_F_(pot_t)->val`	`Potential temperature`
`call field_get_val_s(ivarfl(isca(itotwt)), cvar_totwt)`	`CS_F_(totwt)->val`	`Total water content`
`call field_get_val_s(ivarfl(isca(intdrp)), cvar_intdrp)`	`CS_F_(ntdrp)->val`	`Total number of droplets`
`call field_get_val_s(ivarfl(isca(isca_chem(iesp))), cvar_sc)`	`CS_FI_(chemistry,iesp-1)->val`	`Chemistry species (indexed)`

Coal combustion

Defined in ppincl.f90, ppcpfu.f90 and cs_field_pointer.h.

Fortran code	C code	Description
`call field_get_val_s(isca(inp(iesp)), cvar_inpcl)`	`CS_FI_(np,iesp-1)->val`	`Particles per kg for coal class`
`call field_get_val_s(isca(ixch(iesp)), cvar_xchcl)`	`CS_FI_(xch,iesp-1)->val`	`Reactive coal mass fraction for coal class`
`call field_get_val_s(isca(ixck(iesp)), cvar_xckcl)`	`CS_FI_(xck,iesp-1)->val`	`Coke mass fraction for coal class`
`call field_get_val_s(isca(ixwt(iesp)), cvar_xwtcl)`	`CS_FI_(xwt,iesp-1)->val`	`Water mass fraction for coal class`
`call field_get_val_s(isca(ih2(iesp)), cvar_h2cl)`	`CS_FI_(h2,iesp-1)->val`	`Mass enthalpy for coal class (permeatic case)`
`call field_get_val_s(isca(if1m(iesp)), cvar_f1mcl)`	`CS_FI_(f1m,iesp-1)->val`	`Mean value light volatiles for coal class`
`call field_get_val_s(isca(if2m(iesp)), cvar_f2mcl)`	`CS_FI_(f2m,iesp-1)->val`	`Mean value heavy volatiles for coal class`
`call field_get_val_s(isca(if4m), cvar_f4m)`	`CS_F_(f4m)->val`	`Oxydant 2 mass fraction`
`call field_get_val_s(isca(if5m), cvar_f5m))`	`CS_F_(f5m)->val`	`Oxydant 3 mass fraction`
`call field_get_val_s(isca(if6m), cvar_f6m))`	`CS_F_(f6m)->val`	`Water from coal drying mass fraction`
`call field_get_val_s(isca(if7m), cvar_f7m))`	`CS_F_(f7m)->val`	`Carbon from coal oxidyzed by O2 mass fraction`
`call field_get_val_s(isca(if8m), cvar_f8m))`	`CS_F_(f8m)->val`	`Carbon from coal gasified by CO2 mass fraction`
`call field_get_val_s(isca(if9m), cvar_f9m))`	`CS_F_(f9m)->val`	`Carbon from coal gasified by H2O mass fraction`
`call field_get_val_s(isca(ifvp2m), cvar_fvp2m)`	`CS_F_(fvp2m)->val`	`f1f2 variance`
`call field_get_val_s(isca(iyco2), cvar_yco2)`	`CS_F_(yco2)->val`	`CO2 fraction`
`call field_get_val_s(isca(iyhcn), cvar_yhnc)`	`CS_F_(yhcn)->val`	`HCN fraction`
`call field_get_val_s(isca(iyno), cvar, yno)`	`CS_F_(yno)->val`	`NO fraction`
`call field_get_val_s(isca(iynh3), cvar_ynh3)`	`CS_F_(ynh3)->val`	`NH3 enthalpy`
`call field_get_val_s(isca(ihox), cvar_hox)`	`CS_F_(hox)->val`	`Ox enthalpy`

Compressible

Defined in ppincl.f90 and cs_field_pointer.h.

Fortran code	C code	Description
`call field_get_val_s(isca(ienerg), cvar_energ)`	`CS_F_(e_tot)->val`	`Total energy`
`call field_get_val_s(isca(itempk), cvar_tempk)`	`CS_F_(t_kelvin)->val`	`Temperature, in Kelvin`

Electric arcs

Defined in ppincl.f90 and cs_field_pointer.h.

Fortran code	C code	Description
`call field_get_val_s_by_name("elec_pot_r", cvar_potr)`	`CS_F_(potr)->val`	`Electric potential, real part`
`call field_get_val_s_by_name("elec_pot_i", cvar_poti)`	`CS_F_(poti)->val`	`Electric potential, imaginary part`
`call field_get_val_v_by_name("vec_potential", cvar_potva)`	`CS_F_(potva)->val`	`Vector potential`
`call field_get_val_s_by_name("esl_fraction_01", cvar_ycoel_01)`	`CS_FI_(ycoel,iesp-1)->val`	`Constituent mass fraction`

Gas combustion

Defined in ppincl.f90 and cs_field_pointer.h.

Fortran code	C code	Description
`call field_get_val_s(isca(ifm), cvar_fm)`	`CS_F_(fm)->val`	`Mixture fraction`
`call field_get_val_s(isca(ifp2m), cvar_fp2m)`	`CS_F_(fp2m)->val`	`Mixture fraction variance`
`call field_get_val_s(isca(ifsm), cvar_fsm)`	`CS_F_(fsm)->val`	`Soot mass fraction`
`call field_get_val_s(isca(inpm), cvar_npm)`	`CS_F_(npm)->val`	`Soot precursor number`
`call field_get_val_s(isca(iygfm), cvar_ygfm)`	`CS_F_(ygfm)->val`	`Fresh gas fraction`
`call field_get_val_s(isca(iyfm), cvar_yfm)`	`CS_F_(yfm)->val`	`Mass fraction`
`call field_get_val_s(isca(iyfp2m), cvar_yfp2m)`	`CS_F_(yfp2m)->val`	`Mass fraction variance`
`call field_get_val_s(isca(icoyfp), cvar_coyfp)`	`CS_F_(coyfp)->val`	`Mass fraction covariance`

Radiative transfer

Defined incs_field_pointer.h.

C code	Description
->val	Radiative luminance
->val	Radiative flux
CS_FI_(rad_ets,iesp-1)->val	Radiative flux explicit source term
CS_FI_(rad_its,iesp-1)->val	Radiative flux implicit source term
CS_FI_(rad_abs,iesp-1)->val	Radiative absorption
CS_FI_(rad_emi,iesp-1)->val	Radiative emission
CS_FI_(rad_cak,iesp-1)->val	Radiative absorption coefficient
->val	Radiative incident radiative flux density
->val	Wall thermal conductivity
->val	Wall thickness
->val	Wall emissivity
->val	Boundary radiative flux
->val	Boundary radiative convective flux
->val	Radiative exchange coefficient

Eulerian-Eulerian multiphase flows

Defined incs_field_pointer.h.

C code	Description
->val	Non-condensable gas mass fractions
->val	Particles turbulent kinetic energy Q2
->val	Covariance of the turbulent Q12
->val	XX component of qfp
->val	XY component of qfp
->val	XZ component of qfp
->val	YX component of qfp
->val	YY component of qfp
->val	YZ component of qfp
->val	ZX component of qfp
->val	ZY component of qfp
->val	ZZ component of qfp
->val	Interfacial mass transfer
->val	Interfacial area
->val	Droplets x2
->val	Droplets Sauter mean diameter
->val	Drag between phases
->val	Added mass
->val	Thermal diffusivity
->val	Turbulent thermal diffusivity
->val	dRho over dP
->val	dRho over dH
->val	Turbulent tau12 for particles
->val	Particles lift
->val	Particles turbulent dispersion
->val	Particles drift velocity