Pressure definitions

Surface and volume

Native field

pMean · CellData

Units

m²/s²

Reference

Outlet fixedValue = 0; inlet velocity = 1 m/s.

Evaluation

Score the released pMean values without another offset.

Conversion

Cp = pMean / (0.5 × 1²) = 2 × pMean. This scaling leaves relative L1/L2 unchanged.

Use the static-pressure field. total(p)_coeffMean is a different quantity. Absolute-error diagnostics retain their declared native units.

Sources checked

• AhmedML paper — §B.7, Eq. 36; Table 6 (PDF pp. 24, 26). Defines zero reference, density 1, speed 1 m/s, and relative kinematic pMean.
• Released OpenFOAM case — 0/p; 0/include/initialConditions. Pressure dimensions [0 2 -2 0 0 0 0]; outlet fixedValue inherits pressure 0.

Surface and volume

Native field

pMeanTrim · CellData

Units

m²/s²

Reference

p_ref = 0 at (80, 10, 10) m on the outlet.

Evaluation

Use native pMeanTrim; preserve the outlet reference rather than substituting an upstream or experimental reference.

Conversion

Cp = pMeanTrim / (0.5 × 38.889²); ρ∞ = 1 kg/m³ in this setup.

CpMeanTrim is static pressure coefficient; CptMeanTrim is total pressure coefficient. The uploaded mesh 0/system directories are default ANSA outputs, not the simulation settings.

Sources checked

• DrivAerML paper — §B.2, Eq. 34; §B.3; Tables 3–4. Specifies the outlet reference and warns that moving it changes the pressure values.
• Pinned dataset README — File descriptions: openfoam_meshes. Explicitly excludes the supplied default 0/system folders as evidence of the simulation boundary conditions.

Surface only

Native field

p · PointData

Units

m²/s²

Reference

Zero freestream gauge, recorded in the dataset-owner approval.

Evaluation

Use native p on every required surface point; undo any training mean/std scaling.

Conversion

Cp = p / 450 at U∞ = 30 m/s. Gauge pressure in Pa = 1.184 × p.

The author README calls the surface modality Cp, but its loader reads p directly. Use the explicit owner convention, not the modality label. This audit does not activate wall-shear or volume tasks.

Sources checked

• DrivAerNet++ paper — Appendix B; Table 6 (PDF pp. 18–20). Documents simpleFoam and the 30 m/s, 1.184 kg/m³ flow conditions. It does not alone establish the exact archived p gauge.
• Author surface-pressure loader — sample_point_cloud_with_pressure, lines 66–87. Reads PointData p without coefficient conversion. Its sampled training loader does not define FluidsBench scoring support.
• Recorded owner approval — What is approved; 4 September 2026. Records kinematic gauge pressure, zero freestream reference, and Cp = p / 450.

Surface

Native field

cpavg · PointData

Units

Dimensionless

Reference

Published nominal reference: p_ref = 37330.4 Pa, ρ_ref = 1.31 kg/m³, U_ref = 40 m/s.

Evaluation

Score released cpavg directly. The reference has already been applied.

Conversion

Cp = (P − 37330.4) / 1048 for dimensional P in Pa under the published nominal convention.

Volume

Native field

pressureavg · CellData

Units

Unresolved: paper labels m²/s²; sampled export needs reconciliation

Reference

No additional reference subtraction is implemented by the current evaluator. The tunnel exit is not a fixed-pressure boundary.

Evaluation

The current evaluator compares raw pressureavg values. Preserve that fact without treating it as a confirmed physical convention.

Conversion

Do not apply the surface Cp conversion to pressureavg until the export units and offset are confirmed.

For the dataset, the paper uses nominal inlet conditions; the numerical probe at (−2, 1.3, 0) m is used for the separate experimental validation.

Table 6 calls pressureavg relative kinematic pressure. The pinned run_1 volume XML reports a range of 33105.16015625 to 38447.64453125. Those magnitudes suggest an absolute dimensional export, but a range alone cannot establish units or gauge. The solver/export implementation is not published with this release.

Sources checked

• WindsorML paper — §B.6.4–B.6.5; Tables 5–6 (PDF pp. 19–20). Defines surface Cp and nominal references, distinguishes the validation probe, and labels volume pressureavg relative kinematic pressure.
• Pinned WindsorML dataset — CFD Solver and files. Identifies the commercial Volcano solver and native volume/boundary files.
• Pinned native volume — CellData pressureavg XML RangeMin/RangeMax. Read with bounded HTTP ranges, skipping compressed payloads. The header range is evidence of an ambiguity, not a measured whole-file unit conversion.

Airfoil surface and 2D flow domain

Native field

p · PointData

Units

m²/s²

Reference

Incompressible freestream pressure = 0. The compressible validation case in the paper uses a different convention.

Evaluation

Use native p after undoing training standardization; no extra mean subtraction.

Conversion

Cp = p / (0.5 × U∞²), using each case’s inlet speed. Density is already divided out of p.

The paper’s training-set mean/std normalization is a model preprocessing step, not the pressure reference used for field evaluation.

Sources checked

• AirfRANS paper — Appendix J, Tables 7 and 9 (PDF pp. 29, 31). The incompressible field starts at zero with freestreamPressure; absolute atmospheric pressure is only for compressible validation.
• Official airfrans library — Simulation.__init__; boundary_layer, lines 65–66 and 399–403. Loads native p; the incompressible coefficient divides by 0.5 U∞² without density or another pressure offset.