CAAR in Practice: Results from a 3D Turbulent Flow Simulation
This note documents the results of a full 3D computational fluid dynamics (CFD) simulation evaluating the Convex Automotive Aero Recursion (CAAR) architecture under turbulent external flow.
The goal was not to optimize drag or tune control laws, but to observe how geometry alone governs stress propagation, turbulence localization, and failure envelope shape under identical boundary conditions.
The simulation was run using OpenFOAM v10 with a steady-state RANS solver (simpleFoam) and a k–ε turbulence model. All comparisons were conducted with identical solver settings, mesh resolution, and inflow conditions.
Simulation Setup
Solver
Turbulence Model
Domain
Mesh
Physics
This configuration isolates geometry as the only causal variable.
What CAAR Is Being Evaluated For
CAAR is not a control algorithm. It is an architectural principle: encode stability and interpretability into form, so that pressure, energy, and turbulence are pre-distributed rather than corrected downstream.
Accordingly, the simulation focused on:
Convergence and Numerical Stability
The solver converged cleanly:
This establishes a stable baseline solution suitable for comparative architectural analysis.
Importantly, convergence behavior itself was not forced via relaxation tuning. The geometry allowed the solver to relax naturally toward a steady state.
Observed Results
1. Stress Distribution
Wall shear stress on the CAAR geometry showed:
This indicates that CAAR geometry redistributes mechanical load rather than allowing it to accumulate at singular points.
2. Vorticity Behavior
Vorticity fields revealed:
Rather than suppressing turbulence, CAAR shapes how turbulence resolves, reducing the likelihood of resonance or runaway flow features.
3. Failure Envelope Shape
When visualizing regions exceeding defined stress thresholds, CAAR produced:
This matters architecturally: gradual failure envelopes are interpretable and recoverable, while sharp envelopes are brittle.
Why This Matters
Most autonomous or high-performance systems fail not because limits are exceeded, but because limits are exceeded locally and suddenly.
CAAR demonstrates that:
This aligns with the broader principle that architecture precedes control.
Limitations and Scope
This simulation does not claim:
It demonstrates something more fundamental:
Under identical conditions, geometry alone can materially alter how stress, turbulence, and failure propagate through a system.
That claim is directly supported by the simulation.
Next Steps
Future work will extend this analysis to: