Temporal acceleration of a turbulent channel flow

A. Mathur, S. Gorji, S. He (Lead / Corresponding author), M. Seddighi, A. E. Vardy, T. O'Donoghue, D. Pokrajac

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)
153 Downloads (Pure)


We report new laboratory experiments of a flow accelerating from an initially turbulent state following the opening of a valve, together with large eddy simulations of the experiments and extended Stokes first problem solutions for the early stages of the flow. The results show that the transient flow closely resembles an accelerating laminar flow superimposed on the original steady turbulent flow. The primary consequence of the acceleration is the temporal growth of a boundary layer from the wall, gradually leading to a strong instability causing transition. This extends the findings of previous direct numerical simulations of transient flow following a near-step increase in flow rate. In this interpretation, the initial turbulence is not the primary characteristic of the resulting transient flow, but can be regarded as noise, the evolution of which is strongly influenced by the development of the boundary layer. We observe the spontaneous appearance of turbulent spots and discontinuities in the velocity signals in time and space, revealing rich detail of the transition process, including a striking contrast between streamwise and wall-normal fluctuating velocities.

Original languageEnglish
Pages (from-to)471-490
Number of pages20
JournalJournal of Fluid Mechanics
Early online date27 Nov 2017
Publication statusPublished - 25 Jan 2018


  • pipe flow boundary layer
  • turbulence theory
  • turbulent transition

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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