Sustaining processes from recurrent flows in body-forced turbulence

Abstract

By extracting unstable invariant solutions directly from body-forced three-dimensional turbulence, we study the dynamical processes at play when the forcing is large scale and either unidirectional in the momentum or the vorticity equations. In the former case, the dynamical processes familiar from recent work on linearly-stable shear flows - variously called the Self-Sustaining Process (Waleffe 1997) or Vortex-Wave Interaction (Hall & Smith 1991; Hall & Sherwin 2010) - are important even when the base flow is linearly unstable. In the latter case, where the forcing drives Taylor-Green vortices, a number of mechanisms are observed from the various types of periodic orbits isolated. In particular, two different transient growth mechanisms are discussed to explain the more complex states found.

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Cited by in corpus (8)

• Layer formation in horizontally forced stratified turbulence: connecting exact coherent structures to linear instabilities
• Irreversible mixing by unstable periodic orbits in buoyancy dominated stratified turbulence
• Stabilisation of exact coherent structures in two-dimensional turbulence using time-delayed feedback
• Multi-scale invariant solutions in plane Couette flow: a reduced-order model approach
• On the convergence of the normal form transformation in discrete Rossby and drift wave turbulence
• Minimal model of quasi-cyclic behaviour in turbulence driven by Taylor--Green forcing
• Stabilising nonlinear travelling waves in pipe flow using time-delayed feedback
• Dynamical relevance of periodic orbits under increasing Reynolds number and connections to inviscid dynamics