# Available Output Fields

This section provides a comprehensive overview of all output fields (flow variables) available in Flow360 simulations, organized by their availability across different output types.

Note: All output fields are non-dimensional by default unless otherwise specified. See Scaling Values and Nondimensionalization for information on converting to dimensional values.

# Universal Fields

These fields are available for all output types.

Field Name Description Units
Cp Coefficient of pressure Non-dimensional
Cpt Coefficient of total pressure Non-dimensional
gradW Gradient of primitive solution Non-dimensional
kOmega k and omega (turbulence variables) Non-dimensional
Mach Mach number Non-dimensional
mut Turbulent viscosity Non-dimensional
mutRatio Turbulent viscosity and freestream dynamic viscosity ratio Non-dimensional
nuHat Spalart-Almaras variable Non-dimensional
primitiveVars Density, velocities (u,v,w), and pressure Non-dimensional
qcriterion Q criterion for vortex identification Non-dimensional
residualNavierStokes Navier-Stokes residual Non-dimensional
residualTransition Transition residual Non-dimensional
residualTurbulence Turbulence residual Non-dimensional
s Entropy Non-dimensional
solutionNavierStokes Navier-Stokes solution Non-dimensional
solutionTransition Transition solution Non-dimensional
solutionTurbulence Turbulence solution Non-dimensional
T Temperature Non-dimensional
velocity Velocity vector Non-dimensional
velocity_magnitude Magnitude of velocity vector Non-dimensional
pressure Pressure Non-dimensional
vorticity Vorticity Non-dimensional
vorticityMagnitude Vorticity magnitude Non-dimensional
wallDistance Wall distance Grid unit length
numericalDissipationFactor Numerical dissipation factor sensor Non-dimensional
residualHeatSolver Heat equation residual Non-dimensional
VelocityRelative Velocity with respect to non-inertial frame Non-dimensional
lowMachPreconditionerSensor Low-Mach preconditioner factor Non-dimensional

# Volume and Slice Specific Fields

These fields are available only for Volume Output and Slice Output types.

Field Name Description Units
betMetrics BET Metrics Non-dimensional
betMetricsPerDisk BET Metrics per Disk Non-dimensional
linearResidualNavierStokes Linear residual of Navier-Stokes solver Non-dimensional
linearResidualTurbulence Linear residual of turbulence solver Non-dimensional
linearResidualTransition Linear residual of transition solver Non-dimensional
SpalartAllmaras_hybridModel Hybrid RANS-LES output for Spalart-Allmaras solver (supports both DDES and ZDES) Non-dimensional
kOmegaSST_hybridModel Hybrid RANS-LES output for kOmegaSST solver (supports both DDES and ZDES) Non-dimensional
localCFL Local CFL number Non-dimensional

# Hybrid RANS-LES Output Variables

The SpalartAllmaras_hybridModel and kOmegaSST_hybridModel output fields provide diagnostic variables for hybrid RANS-LES simulations. The specific variables included depend on whether you're using DDES (Delayed Detached Eddy Simulation) or ZDES (Zonal Detached Eddy Simulation) as the shielding function.

# DDES Variables (when shielding_function="DDES")

When using DDES, the hybrid model output includes five key variables:

  1. f_d – The shielding function that delineates the RANS and LES regions. When f_d = 0, the RANS model is fully applied; when f_d = 1, the LES model is used. Intermediate values represent a smooth transition between the two regimes.

  2. r_d – A modified ratio of the modeled length scale to the wall distance, from which f_d is derived.

  3. DDES_lengthRANS – The wall distance from the computational cell to the nearest solid boundary.

  4. DDES_lengthScale – The characteristic DES length scale:

  5. DDES_lengthLES – The characteristic LES length scale:

Among these variables, f_d is the most significant, as it enables users to identify and visualize the regions dominated by RANS and DES behavior within the computational domain.

# ZDES Variables (when shielding_function="ZDES")

When using ZDES, the hybrid model output includes four key variables:

  1. ZDES_fp – The enhanced shielding function that determines whether RANS or LES is used. When ZDES_fp = 0, RANS is active; when ZDES_fp = 1, LES is active. This function is computed from ZDES_fd, ZDES_fR, and ZDES_fp2.

  2. ZDES_fd – Original DDES shielding function used in computing ZDES_fp.

  3. ZDES_fR – Component used in computing ZDES_fp. This is included to disable or inhibit the second shielding function in regions where vorticity magnitude is increasing away from walls - this is designed to disable the secondary shielding function where a shear layer is detected above a wall.

  4. ZDES_fp2 – Causes the model to revert to RANS mode in the outer portion of boundary layers, used in computing ZDES_fp.

# Surface Specific Fields

These fields are available only for Surface Output and Surface Probe Output types.

Field Name Description Units
CfVec Skin friction coefficient vector Non-dimensional
Cf Magnitude of skin friction coefficient Non-dimensional
heatFlux Non-dimensional heat flux Non-dimensional
nodeNormals Wall normals Non-dimensional
nodeForcesPerUnitArea Forces per unit area Non-dimensional
yPlus Non-dimensional wall distance Non-dimensional
wallFunctionMetric Wall function metrics Non-dimensional
heatTransferCoefficientStaticTemperature Surface heat transfer coefficient (static temperature as reference) Non-dimensional
heatTransferCoefficientTotalTemperature Surface heat transfer coefficient (total temperature as reference) Non-dimensional
wall_shear_stress_magnitude Wall shear stress magnitude Non-dimensional
wall_shear_stress_magnitude_pa Wall shear stress magnitude Pascals (Pa) - Available since version 25.2

# Isosurface Specific Fields

These fields are available only for Isosurface Output types.

Isosurface outputs support all universal fields listed above. The most commonly used fields for isosurface visualization are:

  • qcriterion - For vortex identification
  • Mach - For shock wave visualization
  • pressure - For pressure-based isosurfaces
  • Cpt - For total pressure loss visualization

# Custom Variables

User-defined expressions with dimensions. These can be created using the Variable Settings tool or Python API.

By default, the following expressions are available:

Variable Name Expression Description
velocity_with_units solution.velocity Velocity in physical units
velocity_magnitude_with_units math.magnitude(solution.velocity) Velocity magnitude in physical units
pressure_with_units solution.pressure Pressure in physical units
wall_shear_stress_magnitude_with_units solution.wall_shear_stress_magnitude Wall shear stress magnitude in physical units

Note: You can create additional custom variables using the Variable Settings tool or through the Python API. Custom variables can access multiple solver variables and undergo mathematical operations.

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