CHAPERONE AI
Have a different geometry, Reynolds band, or 3D setup?
The public checkpoint proves the method. The product is adapting a physics foundation model to your regime — without erasing what it already knows.
Normalized field error on held-out vortex shedding
Holdout cases above the training Mach band
Original Poseidon families preserved or improved
Median field correlation after autoregressive rollout
High-order CFD is the gold standard — and too slow for early design loops. Foundation physics models are fast, but they only know the flows they were pretrained on. Chaperone-Flow-1.0 is the missing piece: we teach a proven foundation model your missing regimes, keep what it already does well, and ship a drop-in surrogate on the same 4-channel state the base model already uses.
Incompressible flow past a circular cylinder with periodic vortex shedding. Trained across Re ≈ 62–179, tested just beyond that band — the kind of screening loop aero and energy teams run every day.
Kelvin–Helmholtz double shear layers across Mach ≈ 0.20–0.32, with holdout at higher Mach. Useful for mixing, shear-driven instability, and early what-if exploration before a full solver run.
No new architecture. No extra input channels. Geometry is encoded in the existing density field. If you already evaluate Poseidon-B, this checkpoint drops in.
Starting from Poseidon-B (~158M parameters, ETH Zurich CAMLab), we generated solver-grade data for two missing industrial regimes and adapted the full model in one joint run — designed so existing capabilities do not collapse.
We start from Poseidon-B, a published physics foundation model, instead of training a new operator network for every geometry.
Cylinder and mixing-layer trajectories generated with PyFR, then resampled to a common 128×128 state the model can consume at inference time.
Both new flows are taught together, in a fixed training budget, so you get one checkpoint instead of a zoo of one-off surrogates.
Original Poseidon families stay in the mix during training. After adaptation they are near — or better than — the untouched base model.
Error is reported as normalized RMSE against the channel range — a 1.8% score is 1.8% of the observable field span, not a raw residual. New regimes beat a no-change baseline. Existing regimes were not sacrificed to get there.
| Capability | What we measured | Chaperone-Flow-1.0 | Why it matters |
|---|---|---|---|
| New industrial regimes | Cylinder wake, lead-2 field error | 1.8% NRMSE | Usable wake-scale prediction on unseen Re |
| Kelvin–Helmholtz holdout error | 3.8% NRMSE | Works slightly outside the training Mach band | |
| Existing physics retained | Families kept in the training mix | 0.63× / 0.69× | Known regimes got more accurate, not worse |
| Family never shown during adaptation | 1.16× | Still within ~16% of the original model | |
| Tracked original families | 0.63× – 1.16× | One model, not a trade-off | |
| Forecast stability | 20-step autoregressive rollout | NRMSE 0.7% → 1.7% | Error stays bounded over multi-step use |
| Field correlation at step 20 | median 0.985 | The predicted field still looks like the flow |
Means over 3 seeds. NRMSE is RMSE divided by each channel’s value range. Cylinder checkpoint selected on 30 held-out trajectories. Retention is error relative to the unchanged Poseidon-B checkpoint (< 1.0 is better).
Adaptation only works if the data is solver-grade. We generated a dedicated PyFR dataset for the two missing regimes, with a holdout split that tests extrapolation — not memorization.
Teams building their own surrogates can start from the same tensors. For proprietary geometries, Reynolds bands, or 3D setups, we generate the data and adapt the model under a commercial license.
CAE and digital-twin teams in aero, auto, and energy who need fast screening of wakes and mixing — and a path to adapt a foundation model to the next geometry, not a chatbot.
Early design loops, parameter sweeps, and multi-step rollouts inside the validated window. Same 4-channel (ρ, u, v, p) interface as Poseidon-B, on a 128×128 field.
This is a 2D, wake-scale surrogate — not a certification CFD replacement. Fine scales are smoothed; cylinder Re is kept in the 2D-valid band; validated rollout is about four shedding periods.
The public checkpoint proves the method. The product is adapting a physics foundation model to your regime — without erasing what it already knows.