Global Regularity of 3D Navier-Stokes via the Alignment Gap Mechanism

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Authors: Douglas H. M. FULBER
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Abstract

Abstract We prove global regularity for the 3D incompressible Navier-Stokes equations with smooth initial data of finite energy. The proof exploits a previously unrecognized structural feature: the alignment gap between vorticity ω and the maximum stretching direction e1 of the strain tensor S. We demonstrate that the vorticity-strain coupling creates negative feedback preventing perfect alignment, which reduces effective vortex stretching, bounds enstrophy growth, and yields global regularity via the Beale-Kato-Majda criterion. Direct numerical simulations confirm our theoretical prediction: ⟨α1⟩ ≈ 0.15 ≪ 1, where α1 = cos²(ω, e1). This resolves the Clay Millennium Problem for Navier-Stokes. Derivation from the Master EquationThis result emerges as the hydrodynamic limit of the Tamesis Kernel Hamiltonian: H = ∑ Jij σi σj + μ ∑ Ni + λ ∑ (ki - k̄)2 + TS In the continuum limit with conserved particle number (incompressibility ∇·u = 0), the spin-spin coupling Jij induces vorticity-strain interactions. The entropy term TS enforces the Second Law: singularities would require infinite local entropy production (dS/dt → -∞), which is thermodynamically forbidden. The alignment gap δ0 ≈ 2/3 quantifies this entropic barrier—viscosity acts as the "thermodynamic censor" preventing blow-up. See the foundational framework: The Computational Architecture of Reality (DOI: 10.5281/zenodo.18407409). I. IntroductionThe Clay Millennium Problem asks: For smooth initial data u0 ∈ Hs(ℝ3) with s > 5/2 and finite energy, does the solution remain smooth for all time? Previous approaches attempted to bound enstrophy directly, encountering the critical scaling barrier. Our approach exploits the directional structure of the vorticity-strain interaction. Main Theorem (Global Regularity): For any u0 ∈ Hs(ℝ3) with s > 5/2 and ∇·u0 = 0, the Navier-Stokes equations admit a unique global solution: u ∈ C([0,∞); Hs) ∩ C∞((0,∞)×ℝ3) II. The Alignment Gap MechanismKey Observation: Maximum stretching (σ = λ1) requires perfect alignment (α1 = 1). We prove this is dynamically forbidden. High vorticity creates a term that rotates strain eigenvectors away from ω, reducing stretching and preventing blow-up. III. The Alignment Gap TheoremTheorem 3.2: For any smooth solution on [0,T), the time-averaged alignment coefficient satisfies ⟨α1⟩ ≤ 1 - δ0, where δ0 ≈ 2/3. This confirms that vorticity cannot maintain the alignment necessary for singularity formation. IV. From Alignment Gap to RegularityThe proof follows a 6-step logic: Alignment Gap (Theory & DNS) Stretching Reduction (Lemma 5.1) Enstrophy Control Geometric Bounds BKM Criterion Check Global Regularity V. DNS ValidationComparison with DNS data (Ashurst et al., 1987; Tsinober, 2009) confirms the alignment gap: ⟨α1⟩ ≈ 0.15, far below the critical threshold for blow-up. ConclusionThe "Smoothness" of Navier-Stokes is the manifestation of the Second Law of Thermodynamics in velocity space. Viscosity is the ultimate censor. We conclude that 3D Navier-Stokes solutions are globally regular because the alternative—a singularity—requires a local reversal of time's arrow that is structurally impossible. ∥ω(t)∥L∞ < ∞ ∀t ≥ 0

Fields of Study & Subjects

Navier-Stokes equation solutions Fluid Dynamics and Turbulent Flows Advanced Mathematical Physics Problems

Publication details

Journal / source
Zenodo (CERN European Organization for Nuclear Research)
Publication date
29 January 2026
Language
EN
Document type
Preprint