Self-sustained process at large scales in turbulent channel flow

Yongyun Hwang (1) , Carlo Cossu (2)

1 LadHyX - Laboratoire d'hydrodynamique
2 IMFT - Institut de mécanique des fluides de Toulouse

Large-scale motions, important in turbulent shear flows, are frequently attributed to the interaction of structures at smaller scales. Here we show that, in a turbulent channel at Reτ≈550, large-scale motions can self-sustain even when smaller-scale structures populating the near-wall and logarithmic regions are artificially quenched. This large-scale self-sustained mechanism is not active in periodic boxes of width smaller than Lz≈1.5h or length shorter than Lx≈3h which correspond well to the most energetic large scales observed in the turbulent channel.

Mots clés: Turbulence; Turbulent channel flows; Streaks; Channel flow; Flow simulation

Domaines: Mécanique des fluides [physics.class-ph]; Mécanique des fluides [physics.class-ph]

Yongyun Hwang, Carlo Cossu. Self-sustained process at large scales in turbulent channel flow. Physical Review Letters, 2010, vol. 105, pp. 1-4. ⟨10.1103/PhysRevLett.105.044505⟩. ⟨hal-00925804⟩