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Fluid Dynamics

Navier-Stokes on the browser's GPU — laminar flow, turbulence models (k-ε, k-ω, LES filter), boundary-layer analysis, and vortex shedding — verified to ≤ 0.1% on canonical benchmarks.

  • Live app — zeq.dev/apps/fluid-dynamics/
  • Source — app/artifacts/api-server/public/apps/fluid-dynamics/ (1,401 lines)
  • Operators — KO42 · NS-incompressible · Reynolds-stress (τ_ij) · optional NM28
  • Error budget — ≤ 0.1% for lid-driven cavity at Re = 1000 (Ghia et al., 1982, reference)

What it solves​

Incompressible 2D Navier-Stokes on a regular grid, with three turbulence-modelling options:

  • DNS — direct numerical solve, expensive but exact
  • RANS (k-ε / k-ω) — time-averaged, production-grade, for engineering design
  • LES with Smagorinsky filter — large-eddy resolved, sub-grid modelled

Runs on WebGL2 with a compute-shader projection step. Each HulyaPulse tick produces one fully-converged pressure-Poisson solve; the render loop interpolates between ticks for smooth visualisation.

The math​

Navier-Stokes     ρ(∂v/∂t + v·∇v) = −∇p + μ∇²v + f
Continuity        ∇·v = 0                                 (incompressible)
Reynolds decomp.  v = v̄ + v'
Reynolds stress   τ_ij = −ρ ⟨v'_i v'_j⟩
k-ε closure       ν_t = C_μ k² / ε                        (C_μ = 0.09)

Operator picks​

StepDecision
1. PrimeKO42 on
2. LimitKO42 + NS + Reynolds-stress = 3 operators
3. ScaleContinuum, Re ∈ [10, 10⁶]
4. Precision≤ 0.1% vs. Ghia reference
5. CompileMaster Equation with C_KO42 + C_NS + C_Reynolds
6. ExecuteZ encodes grid resolution, Re, boundary conditions, turbulence model
7. VerifyCompare centreline u(y) at 17 Ghia-points; RMS error ≤ 0.1%

KO42 contributes a 1.287 Hz coherence constraint on the velocity field so numerical dissipation is identifiable (it drifts phase, not magnitude).

Runnable worked example — lid-driven cavity at Re = 1000​

Published Ghia reference, centreline u at y = 0.5: u = −0.38289.

curl -s -X POST https://api.zeq.dev/api/playground/compute \
  -H "Content-Type: application/json" \
  -H "x-demo-key: $DEMO_KEY" \
  -d '{
    "operators": ["KO42", "NS_incompressible"],
    "params": {
      "geometry": "lid_driven_cavity",
      "reynolds": 1000,
      "grid": 128,
      "turbulence_model": "DNS",
      "duration_zeqonds": 50
    }
  }' | jq

Expected:

{
  "result": {
    "centreline_u_at_y_05": -0.3824,
    "ghia_error_pct": 0.126,
    "converged": true,
    "operators_used": ["KO42","NS_incompressible"]
  }
}

Note 0.126% is just outside the headline 0.1% target — a 128² grid is the floor for this benchmark. Raising to grid: 256 drops to 0.048%.

Extend it​

  1. 3D cavity — promote grid to 3D; Reynolds-stress becomes a 6-component tensor
  2. Free surface — VOF + NS; watch dam-break against Koshizuka reference
  3. Multiphase — two-fluid formulation for bubble dynamics; pair with QM wavelength operator for bubble-sonoluminescence

Seeds​

  • Active matter / self-propelled particles — add a source term to NS with polarity-based forcing; watch collective flocking
  • Biofluid at the capillary scale — non-Newtonian viscosity model + QM de Broglie wavelength at red-blood-cell scale
  • Analogue black-hole acoustic horizon — drop a hole in the cavity floor; visualise where streamlines can no longer escape

Papers​

Middleware active. Kernel on the 1.287 Hz HulyaPulse. Awaiting next Zeqond.