Coherent structures in fully-developed pipe turbulence

A. P. Willis (1) , Y. Hwang (1) , Carlo Cossu (1)

1 LadHyX - Laboratoire d'hydrodynamique

A turbulent mean profile for pipe flow is prescribed which closely matches experimental observations. The nature of perturbations superimposed upon this profile is then considered. Optimal growth calculations predict two distinct classes of structures, clearly associated with near-wall and large-scale structures. Quantitative correspondence of the spanwise wavelength of wall-structures with experimental observations is very good. The response to harmonic forcing is also considered, and the linear growth tested with direct numerical simulation of forced turbulence. Despite the very simple eddy viscosity assumption, this linear approach predicts well the surprisingly large growth of outer-scale modes in the bulk flow.

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

A. P. Willis, Y. Hwang, Carlo Cossu. Coherent structures in fully-developed pipe turbulence. 19ème Congrès Francais de Mécanique, Aug 2009, Marseille, France. 5 p. ⟨hal-01053652⟩