MODEL TEST · REFERENCE REPRESENTATION

Raw POD

Direct weighted POD of the unaveraged CFD snapshot fields. It is the simplest current reference: compress the spatial fields first, then use phase-conditioned modal coefficients and speed interpolation for deployment.

PRODUCTIVE · DEPLOYEDReference ROM with a live multi-field demonstrator

OVERVIEW

Minimal structure before adding richer dynamics assumptions

Data

4,480 snapshots

Seven speeds × 640 snapshots, all mapped to one common 96,000-cell volume geometry and 840-wall-face surface geometry.

Representation

Field-wise weighted POD

u, w, volume Cp, ω, surface Cp and surface Cf are decomposed separately with physical volume/area weighting.

Time

Phase-conditioned coefficients

The ten cycles are condensed into a stable periodic coefficient trajectory for indefinite direct-time playback.

Speed

Continuous interpolation

The fitted all-seven demonstrator evaluates integer speeds between 50 and 200 km/h.

RESULT SNAPSHOT

Compact enough to deploy, with different ranks by field

37u modes≥99.5% centered energy

56w modes≥99.5% centered energy

16volume Cp modes≥99.5% centered energy

28ω modes≥99.5% centered energy

First five raw POD modes for several volume fields — Representative raw-POD modal structures. The basis is global across all seven U-sweep speeds.

Takeaway

Raw POD provides a strong transparent baseline and a working deployment path. Its main limitation is not that it cannot compress the flow, but that global modes can mix coherent periodic motion with cycle-to-cycle and secondary dynamics.

LIVE DEMONSTRATOR

Raw-POD real-time reconstruction

Explore u, w, in-plane velocity magnitude, Cp and ω while Cd/Cl are reconstructed from synchronized surface POD quantities.

Reference deployment

Evidence boundaryThis all-seven fitted model demonstrates reconstruction and deployment. It is not a substitute for unseen-speed validation.

SUMMARY

Why it stays the reference

Strength

Simple, inspectable and deployable with relatively few modeling assumptions.

Limitation

Coherent and residual dynamics are not explicitly separated, so modal rank and temporal coefficients may carry several types of variability at once.

Role

Use Raw POD as the baseline that more structured approaches must beat or clarify.

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