I tried numerically simulating a finite-scale version of the collapsing-core conditions from OpenAI’s Navier–Stokes paper

This is not a reproduction of the proof or a blow-up claim. It is a decoupled pseudo-spectral DNS of a finite-scale surrogate inspired by the paper’s collapsing similarity geometry. The velocity field is not fed back into the solver; the DNS evolves only under the constructed external force. The run uses Fourier pseudo-spectral discretization, strict 2/3 de-aliasing and IMEX-RK2, with spectral-tail and manufactured-solution checks. Source, diagnostics and frozen-force runs: https://github.com/CokieMiner/nsblowup