Layered anisotropic stratified turbulence in columnar Taylor–Green vortices

We use direct numerical simulations (DNSs) of columnar Taylor–Green vortex arrays under stable density stratification to characterise the route to, and the properties of, layered anisotropic stratified turbulence (LAST). Building on the linear stability analysis of Guo et al. (2024 J. Fluid Mech. , vol. 997, A34) and the convection-driven turbulence transition reported by the same authors (2025 J. Fluid Mech. , vol. 1016, A44), we extend the DNS database to Froude numbers italic Fr less than or slanted equals 0.25 Fr ⩽ 0.25 $\textit {Fr}\leqslant 0.25$ and Reynolds numbers italic Re Re $\textit {Re}$ up to 3200 3200 $3200$ . In this strongly stratified regime, the vortex array breaks down through a shear-driven path: vertical shear layers that form spontaneously in the zigzag-deformed base flow destabilise locally and transition to LAST, in contrast with the convection-driven path identified at italic Fr greater than or slanted equals 0.5 Fr ⩾ 0.5 $\textit {Fr}\geqslant 0.5$ . Four flow regimes are charted, two of which follow the buoyancy-driven scaling script l Subscript v Baseline proportional to upper U Subscript h Baseline divided by upper N ℓ v ∝ U h / N $\ell _v\propto U_h/N$ : LAST and a layered anisotropic viscously affected flow (LAVAF) regime, where script l Subscript v ℓ v $\ell _v$ is the vertical integral scale, upper U Subscript h U h $U_h$ the horizontal velocity and