Meandering dynamics of streamwise vortex pairs in afterbody wakes

The paper’s bi-global linear stability analysis of a fitted counter-rotating Batchelor vortex pair finds an m=1 elliptic instability with ω ≈ 1.988 + 0.0417i at k = 2.0 (temporal) and k ≈ ±2.0138 − 0.0473i at ω = 2.0 (spatial), phase speed ≈ 0.99, and a ~30° dipole tilt; POD spectra peak near StD ≈ 0.32. The candidate reproduces these core results and methodology. The only tension is the onset k: the paper reports instability for 1 ≤ k ≤ 3, whereas the candidate observes near-neutral growth emerging at k ≈ 0.5 with very small ωi; this is plausibly due to discretization and boundary differences. The candidate’s axial-velocity ablation test (u ≡ 0) aligns with the paper’s conclusion that axial velocity (strain) is essential, although that specific test is not shown in the paper. Overall, the main numerical values, mode structure, and conclusions match closely.