{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"61b753fa875cee2fadfc11e1fa830d4354948a618986178c260f702ca73e5e30","created":"2026-10-03T07:18:04Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"33b0e4d1ab72df0963ce4790a3c4a61f7a80b58eef39184fd6b677c8114c3d24","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"mechanism","assisted_by":[],"external_id":"fluid.shear-transition.band-pattern","kind":"phenomenon","literature_status":"partially-resolved","n":"1","parents":[],"plain":"In flows between parallel plates near the onset of turbulence, turbulent and smooth regions arrange themselves into tilted stripes with a definite angle and spacing. A theory that predicts these numbers from the flow equations is incomplete.","posed_since":"2002","precise":"In plane Couette and plane Poiseuille flows near onset, laminar-turbulent bands form at angles of roughly 20 to 40 degrees to the streamwise direction with wavelengths of order $10^{2}$ half-gaps. Derive the selected angle and wavelength and their Re dependence from the Navier-Stokes equations, including the large-scale flow that accompanies the bands.","problem_ref":null,"references":"","settled_by":"A reduced theory derived from the Navier-Stokes equations predicting angle and wavelength within 10 percent across Re, checked by DNS in large domains.","status_note":"Simulations reproduce the bands and analyses of the large-scale flow explain parts of the selection (Gome, Tuckerman, Barkley 2023); a closed derivation of the angle is lacking.","title":"What selects the angle and wavelength of transitional turbulent bands?","topic_ref":"2aa8cdcaa55f798dfb19771ba7be3d165d6aebb316dba50bbe9ddce450fd9038"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"a9a3b94079f25f52bda513cb727cc7618ac8da5bd3c4dbd6343e66a4bd10f3f0","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"1d22dcf6a3d42ad9b02fae6a251c9874b983a97423a194656ccb1e8576b4a8d7","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"L_ThhZEzNEukxIc4TIjfAkhAuvYBaewLmeLaNve79m9xtbNGvF3SiiIP79W454-sRiTCcS6f02K_BrNcMmjKBA"},"schema":"pubphys.envelope/1"},"record_hash":"a9a3b94079f25f52bda513cb727cc7618ac8da5bd3c4dbd6343e66a4bd10f3f0","leaf_index":1429}