14.3. The FENSAP Solution File – Binary Format

The FENSAP binary flow solution file is written with the following structure:

On the first line,

  • nnode

(32-bit integer) Number of nodes (must be identical to nnode in the grid file);

  • nfields

(32-bit integer) Number of variable fields (6 for Euler, and up to 17 for Navier-Stokes);

  • goveqns

(32-bit integer) Flag for the governing equations (1 for Euler, 8 for Navier-Stokes);

  • kturb

(32-bit integer) Flag for the turbulence model (0 for a laminar flow, 1 for the Spalart-Allmaras one-equation turbulence model, 3 or 4 for kay-epsilon, 5 or 6 for kay-omega);

  • lvltime

(32-bit integer) Indicates the number of time levels stored in the file.

The fields are identified by 34-character labels. The first 4 characters of the label are the flow variable key names in FIELDVIEW and the following 30 characters describe the field. The first six labels are always:

 
 DENS - Density (kg/m3 )
 PRES - Pressure (N/m2 )
 XVELV1 - Velocity (m/s) 
 YVELV2 - Velocity (m/s) 
 ZVELV3 - Velocity (m/s) 
 TEMP - Static temperature (K)

If the flow solution is viscous (goveqns=8) and the turbulence model is Spalart-Allmaras (kturb=1), the next six labels are:

 
 KAY - Nutilde (m/s)2  
 WLDS - Wall distance (m) 
 VISL - Laminar viscosity (kg/m s) 
 VIST - Turbulent viscosity (kg/m s) 
 YPLS - y-plus 
 UPLS - u-plus

Note:  When variable surface sand-grain roughness is imposed, the wall distance in the solution file is replaced with the sand-grain roughness height, whose label is WLDSroughness height (m). The roughness height will have non-zero values away from the walls.

If the flow solution is viscous (goveqns=8) and the turbulence model is k-epsilon (kturb=3 or kturb=4), the next six labels are:

 
 KAY - Kay (m/s)2  
 EPSI - Epsilon (m/s2 )
 VISL - Laminar viscosity (kg/m s) 
 VIST - Turbulent viscosity (kg/m s) 
 YPLS - y-plus 
 UPLS - u-plus

If the flow solution is viscous (goveqns=8) and the turbulence model is k-omega (kturb=5 or kturb=6), the next six labels are:

 
 KAY - Kay (m/s)2  
 OMEG - Omega (1/s) 
 VISL - Laminar viscosity (kg/m s) 
 VIST - Turbulent viscosity (kg/m s) 
 YPLS - y-plus 
 UPLS - u-plus

If the Navier-Stokes equations have been used to obtain the solution, the solution is complemented by the three components of the shear stress vector, expressed in Pascal (N/m2):

 
 XSFOSF1 - Shear stress (Pa); Shear 
 YSFOSF2 - Shear stress (Pa) 
 ZSFOSF3 - Shear stress (Pa)

If the full energy equation has also been used, the flow solution is complemented by the Classical and Gresho heat fluxes, both expressed in W/m2:

 
 CLAS - Classical heat flux (W/m2 )
 GRES - Gresho heat flux (W/m2 )

Note:  Heat fluxes are zero everywhere except on wall surfaces.

The values contained in the vector dble_cnst (64-bit double precision) of length num_cnst (=24 in this version of FENSAP-ICE) are reference values used to obtain the solution. Some of them are important for FENSAP, DROP3D and ICE3D:

 rgas, gamma, tinf, pinf, machinf, velx, vely, velz, velinf, hinf, xkeinf, rhoinf, p0inf, zmuinf, reinf, prinfnd, entrinf, reinf, omgx, omgy, omgz, zero, zero, zero

  • rgas

Gas constant

  • gamma

Specific heat ratio

  • tinf

Reference static temperature

  • pinf

Reference static pressure

  • machinf

Freestream Mach number

  • velx

X-component of the freestream velocity (non-dimensional)

  • vely

Y-component of the freestream velocity (non-dimensional)

  • velz

Z-component of the freestream velocity (non-dimensional)

  • velinf

Magnitude of the freestream velocity

  • hinf

Freestream static enthalpy

  • xkeinf

Freestream dynamic pressure (rV2)

  • rhoinf

Reference density

  • p0inf

Reference total pressure

  • zmuinf

Reference dynamic viscosity

  • reinf

Reynolds number

  • prinfnd

Freestream reference pressure (non-dimensional)

  • entrinf

Freestream reference entropy

  • length

Effective characteristic length

  • omgx

X-component of the rotational velocity

  • omgy

Y-component of the rotational velocity

  • omgz

Z-component of the rotational velocity

  • zero

Unused (0.0d0)

  • zero

Unused (0.0d0)

  • zero

Unused (0.0d0)

Next, the time (64-bit double precision) and time steps dt (64-bit double precision) are written. For a steady flow (lvltime=1), this line becomes 0.0d0.

Finally, each variable field (64-bit double precision) is written following the same order as the labels. If the solution was steady-state (lvltime=1) only one time level will be found. For unsteady solutions (lvltime=2 or lvltime=3) two or three time levels of the pressure, velocity components and temperature will be written to the file.

Note:  All flow variables are saved in dimensional form, except y_plus and u_plus when the solution has been obtained with the Spalart-Allmaras turbulence model. If the input grid is in cylindrical coordinates, the flow solution is also saved in this reference system.