fluidsim

# FluidSim Use FluidSim 0.9.0 as a framework for Python-defined numerical solvers, especially periodic Cartesian pseudospectral CFD. Upstream FluidSim is CeCILL-2.1; the MIT frontmatter license applies only to this skill. This skill does **not** treat a completed run, a stable time step, a smooth plot, or a closed program exit as evidence of numerical convergence or physical validity. ## Required workflow 1. State equations, units or nondimensionalization, geometry, boundaries, initial conditions, forcing, observables, and acceptance criteria. 2. Select a verified solver and inspect its generated default parameters. 3. Create a strict JSON plan with explicit CPU, RAM, disk, wall-time, output-file, timestep, CFL, resolution, and dealiasing bounds. 4. Run the bundled validator and resource estimator. 5. Generate and review a dry-run script. It does nothing unless executed with an explicit config-ID acknowledgement. 6. Run one tiny serial pilot. Inspect budgets, divergence/constraints, spectral tails, CFL/time-step history, and output growth. 7. Refine grid and time step independently. Check conservation/budget residuals and observable sensitivity. 8. Only then prepare a site-specific MPI job. Never submit or launch MPI automatically. 9. Preserve config, script, `uv.lock`, package/platform/backend versions, logs, output inventory, checksums, and restart lineage. Stop if physical assumptions, units, boundary conditions, forcing semantics, resolution crit...