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Output Variables

This section discusses the available output variables for volume, surface, probe, and slice/isosurface outputs. We also discuss how to get time-averaged variables output. Note that .nam file is written for volume, surface, and restart output files. These .nam files contain a list of the variables included in the Plot3D function file. Some visualization packages can read these files in at the same time as the function file so that the proper names are associated with the variables.

Volume Output Variables

The list of available volume output variables is listed below along with a brief description.

  • Pressure: Pressure, [Pa].
  • VelocityX: X-direction velocity, [m/s].
  • VelocityY: Y-direction velocity, [m/s].
  • VelocityZ: Z-direction velocity, [m/s].
  • Temperature: Temperature, [K].
  • Cp: Coefficient of pressure.
  • nut: Spalart-Allmaras turbulence model working variable, [m^2/s].
  • k: Turbulent kinetic energy in the k-omega BSL and SST models, [m^2/s^2].
  • omega: Specific dissipation rate in the k-omega BSL and SST models, [1/s].
  • intermittency: Intermittency factor in the Langtry-Menter transition model.
  • ReTheta: Transition-onset momentum thickness Reynolds number in the Langtry-Menter transition model.
  • ResPressure: Residual of the conservation of mass equation.
  • ResVelocityX: Residual of the conservation of momentum equation in the x-direction.
  • ResVelocityY: Residual of the conservation of momentum equation in the y-direction.
  • ResVelocityZ: Residual of the conservation of momentum equation in the z-direction.
  • ResTemperature: Residual of the conservation of energy equation.
  • ResNut: Residual of the Spalart-Allmaras turbulence model equation.
  • ResK: Residual of the turbulent kinetic energy equation in the k-omega BSL and SST turbulence models.
  • ResOmega: Residual of the specific dissipation rate equation in the k-omega BSL and SST turbulence models.
  • ResInt: Residual of the intermittency equation in the Langtry-Menter transition model.
  • ResRet: Residual of the transition-onset momentum thickness Reynolds number equation in the Langtry-Menter transition model.
  • uu: X-direction velocity squared, [m^2/s^2].
  • uv: X-direction velocity times Y-direction velocity, [m^2/s^2].
  • uw: X-direction velocity times Z-direction velocity, [m^2/s^2].
  • vv: Y-direction velocity squared, [m^2/s^2].
  • vw: Y-direction velocity times Z-direction velocity, [m^2/s^2].
  • ww: Z-direction velocity squared, [m^2/s^2].
  • uT: X-direction velocity times Temperature, [m K/s].
  • vT: Y-direction velocity times Temperature, [m K/s].
  • wT: Z-direction velocity times Temperature, [m K/s].
  • Mach: Mach number.
  • sos: Speed of sound.
  • Density: Density, [kg/m^3].
  • rhou: X-direction momentum, [kg m/s].
  • rhov: Y-direction momentum, [kg m/s].
  • rhow: Z-direction momentum, [kg m/s].
  • rhoE: Total energy, [kg m^2/s^2].
  • Entropy: Entropy, [kg m^2/(s^2 K)].
  • EddyViscosity: Turbulent eddy viscosity, [kg/(m s)].
  • EddyViscosityRatio: Turbulent eddy viscosity divided by reference viscosity.
  • StrainRateMagnitude: Magnitude of the strain rate.
  • KFromSA: Estimate of the turbulent kinetic energy from the Spalart-Allmaras turbulence model using Bradshaw's hypothesis.
  • EpsilonFromSA: Estimate of isotropic turbulent dissipation from the Spalart-Allmaras turbulence model using Bradshaw's hypothesis.
  • SSTBlendingF1: The F1 blending function in the k-omega SST turbulence model.
  • SSTBlendingF1Var1: First input in the arg1 function in the F1 blending function in the k-omega SST turbulence model.
  • SSTBlendingF1Var2: Second input in the arg1 function in the F1 blending function in the k-omega SST turbulence model.
  • SSTBlendingF1Var3: Third input in the arg1 function in the F1 blending function in the k-omega SST turbulence model.
  • SSTBlendingF2: The F2 blending function in the k-omega SST turbulence model.
  • fw: The fw function in the Spalart-Allmaras turbulence model.
  • Qcriterion: Q-criteria, [1/s^2].
  • RhoGradMag: Magnitude of the density gradient vector.
  • ShockSurface: Shock Surface.
  • VelocityMag: Magnitude of the velocity vector, [m/s].
  • DPressureDt: Time-derivative of the pressure.
  • DucrosSensor: Originally the Ducros sensor, now plots the selected upwind sensor.
  • ShockSensor: Shock sensor based on second difference of pressure, values are controlled by dswitch in navierstokes.convective.
  • Vorticity: Magnitude of vorticity vector, [1/s].
  • XVorticity: X-direction of vorticity vector, [1/s].
  • YVorticity: Y-direction of vorticity vector, [1/s].
  • ZVorticity: Z-direction of vorticity vector, [1/s].
  • Helicity: Helicity which is the dot-product of velocity and vorticity vectors, [m^2/s^2].
  • fr1: Function for Rotation-Curvature correction, set to unity if userc is False.
  • csgsDynSmag: The spatially varying Csgs coefficient when using the Dynamic Smagorinsky sub-grid scale model.
  • DLen: Local length scale used in both LES and HRLES models, [m].
  • DelS: Local grid length scale, depends on option set in navierstokes.turbulenceModel.gridLengthScale.
  • DelM: Maximum grid length scale at each node.
  • DelJ: Grid spacing in the j-coordinate direction at each node.
  • DelK: Grid spacing in the k-coordinate direction at each node.
  • DelL: Grid spacing in the l-coordinate direction at each node.
  • fd: Shielding or constraint function used in HRLES models.
  • fdr: Original DDES shielding function used as part of fd in navierstokes.turbulenceModel.mode = zdesmode7.
  • fpp: Enhanced protection function used as part of fd in navierstokes.turbulenceModel.mode = zdesmode7.
  • fr: Inhibition function used as part of fd in navierstokes.turbulenceModel.mode = zdesmode7.
  • iblank: Grid node status value: 1 for compute, 0 for blank, -nz for fringe where nz is the zone number of the donor cell.
  • smin: Minimum wall-distance.
  • sminvecx: X-direction of the vector from the grid node to the closest point on the wall.
  • sminvecy: Y-direction of the vector from the grid node to the closest point on the wall.
  • sminvecz: Z-direction of the vector from the grid node to the closest point on the wall.
  • dt: Maximum possible explicit time-step at each node based on timestepping.explicitCFLLimit.
  • dtinc: Maximum possible explicit convective time-step (no speed of sound) at each node based on timestepping.explicitCFLLimit.
  • ug: X-direction grid velocity for a moving grid.
  • vg: Y-direction grid velocity for a moving grid.
  • wg: Z-direction grid velocity for a moving grid.
  • x: X-grid coordinate at current time-level.
  • y: Y-grid coordinate at current time-level.
  • z: Z-grid coordinate at current time-level.
  • xn: X-grid coordinate at previous time-level.
  • yn: Y-grid coordinate at previous time-level.
  • zn: Z-grid coordinate at previous time-level.
  • wn1: Conserved variable 1 at previous time-level.
  • wn2: Conserved variable 2 at previous time-level.
  • wn3: Conserved variable 3 at previous time-level.
  • wn4: Conserved variable 4 at previous time-level.
  • wn5: Conserved variable 5 at previous time-level.
  • turvarn1: Turbulence model variable 1 at previous time-level.
  • turvarn2: Turbulence model variable 2 at previous time-level.
  • Sij11: Component 1,1 of strain rate tensor at current time-level.
  • Sij12: Component 1,2 of strain rate tensor at current time-level.
  • Sij13: Component 1,3 of strain rate tensor at current time-level.
  • Sij22: Component 2,2 of strain rate tensor at current time-level.
  • Sij23: Component 2,3 of strain rate tensor at current time-level.
  • Sij33: Component 3,3 of strain rate tensor at current time-level.
  • Sijn11: Component 1,1 of strain rate tensor at previous time-level.
  • Sijn12: Component 1,2 of strain rate tensor at previous time-level.
  • Sijn13: Component 1,3 of strain rate tensor at previous time-level.
  • Sijn22: Component 2,2 of strain rate tensor at previous time-level.
  • Sijn23: Component 2,3 of strain rate tensor at previous time-level.
  • Sijn33: Component 3,3 of strain rate tensor at previous time-level.
  • dj: Metric term jacobian at current time-level.
  • djn: Metric term jacobian at previous time-level.
  • djh: Metric term jacobian used with higher-order metrics.
  • dij: Metric term jacobian used in conservative time-metric routine.
  • rtxyz11: Metric term J^(-1)d(xi)/dt.
  • rtxyz12: Metric term J^(-1)d(xi)/dx.
  • rtxyz13: Metric term J^(-1)d(xi)/dy.
  • rtxyz14: Metric term J^(-1)d(xi)/dz.
  • rtxyz21: Metric term J^(-1)d(eta)/dt.
  • rtxyz22: Metric term J^(-1)d(eta)/dx.
  • rtxyz23: Metric term J^(-1)d(eta)/dy.
  • rtxyz24: Metric term J^(-1)d(eta)/dz.
  • rtxyz31: Metric term J^(-1)d(zeta)/dt.
  • rtxyz32: Metric term J^(-1)d(zeta)/dx.
  • rtxyz33: Metric term J^(-1)d(zeta)/dy.
  • rtxyz34: Metric term J^(-1)d(zeta)/dz.
  • ibmark: Status of a grid node with respect to immersed boundary, 1 - inside, 0 - outside.
  • globalindex: Index of a grid node in the global index array.
  • referenceindex: Reference index of a grid node.
  • tileid: Which tile a grid node is assigned to.
  • procid: Which MPI rank a grid node is assigned to.
  • source1: User provided/specified source for equation 1.
  • source2: User provided/specified source for equation 2.
  • source3: User provided/specified source for equation 3.
  • source4: User provided/specified source for equation 4.
  • source5: User provided/specified source for equation 5.
  • nx: X-direction component of the unit normal vector to the closest wall point.
  • ny: Y-direction component of the unit normal vector to the closest wall point.
  • nz: Z-direction component of the unit normal vector to the closest wall point.
  • nondimdensity: Plot3D solution file style non-dimensional density.
  • nondimrhou: Plot3D solution file style non-dimensional x-direction momentum.
  • nondimrhov: Plot3D solution file style non-dimensional y-direction momentum.
  • nondimrhow: Plot3D solution file style non-dimensional z-direction momentum.
  • nondimrhoe: Plot3D solution file style non-dimensional total energy.
  • adjointp: Adjoint variable for the conservation of mass equation.
  • adjointu: Adjoint variable for the conservation of momentum equation in the x-direction.
  • adjointv: Adjoint variable for the conservation of momentum equation in the y-direction.
  • adjointw: Adjoint variable for the conservation of momentum equation in the z-direction.
  • adjointt: Adjoint variable for the conservation of energy equation.
  • adjointtur1: Adjoint variable for the Spalart-Allmaras turbulence model equation.
  • aspectratioj: Maximum aspect ratio in the j-coordinate direction.
  • aspectratiok: Maximum aspect ratio in the k-coordinate direction.
  • aspectratiol: Maximum aspect ratio in the l-coordinate direction.
  • planarskewnessj: Planar skewness in the j-coordinate direction.
  • planarskewnessk: Planar skewness in the k-coordinate direction.
  • planarskewnessl: Planar skewness in the l-coordinate direction.
  • stretchingratioj: Maximum stretching ratio in the j-coordinate direction.
  • stretchingratiok: Maximum stretching ratio in the k-coordinate direction.
  • stretchingratiol: Maximum stretching ratio in the l-coordinate direction.
  • ARquality: Aspect ratio quality metric.
  • PSquality: Planar skewness quality metric.
  • SRquality: Stretching ratio quality metric.
  • minEdgeLength: Minimum edge length connected to the node.
  • maxEdgeLength: Maximum edge length connected to the node.
  • cellvolume: Volume of the dual-cell at the node, equivalent to the inverse Jacobian of the coordinate transformation.
  • cuberootcellvolume: Cube root of the volume of the dual-cell at the node.

Surface Output Variables

The list of surface specific output variables is listed below along with a brief description. Note that since subsets are also considered surface data that any of the volume outputs can also be output for surface subsets. For example, Cp can be output for volume, surface, or subset surfaces.

  • yplus: Wall spacing in viscous units.
  • xi1plus: Transverse spacing direction 1 in viscous units.
  • xi2plus: Transverse spacing direction 2 in viscous units.
  • ustar: Friction velocity.
  • Cf: Skin-friction magnitude.
  • Cfx: Skin-friction in the x-direction.
  • Cfy: Skin-friction in the y-direction.
  • Cfz: Skin-friction in the z-direction.
  • signedCf: Signed skin-friction magnitude where the sign is determined from the dot product of the skin friction and freestream velocity vectors.
  • SAturbIndex: Spalart-Allmaras based turbulence index used to detect transition.
  • PanelWeight: The weight of each quad used in aerodynamic force and moment integration to account for overlapping surface grids.

Probe/Slice/Isosurface Output Variables

Probes, slices, and isosurfaces are similar to subset surfaces. All volume output variables can be requested on either probes, slices and/or isosurfaces. In addition, probe surfaces can request skin-friction and yplus variables where a wall-model, selected by the user, is used to compute the values on the probe surface(s).

Averaging

In order to output time-averaged variable, the user can simply append avg to the end of a variable name and a time-averaged version will be output. For example, velocityXavg and Cfxavg will output the time-averaged x-direction velocity and x-direction skin-friction. A more detailed example can be found in the Hybrid RANS-LES tutorial. Note that the averaging can be used to compute resolved turbulent stresses by adding velocityXavg, velocityYavg, velocityZavg, temperatureavg, uuavg, uvavg, uwavg, vvavg, vwavg, wwavg, uTavg, vTavg, wTavg and computing:

  • \(\overline{u u}\) = uuavg - velocityXavg velocityXavg
  • \(\overline{u v}\) = uvavg - velocityXavg velocityYavg
  • \(\overline{u w}\) = uwavg - velocityXavg velocityZavg
  • \(\overline{v v}\) = vvavg - velocityYavg velocityYavg
  • \(\overline{v w}\) = vwavg - velocityYavg velocityZavg
  • \(\overline{w w}\) = wwavg - velocityZavg velocityZavg
  • \(\overline{u T}\) = uTavg - velocityXavg temperatureavg
  • \(\overline{v T}\) = vTavg - velocityYavg temperatureavg
  • \(\overline{w T}\) = wTavg - velocityZavg temperatureavg