Unsteady Turbulence and Friction

Unsteady flow is commonplace in engineering systems as well as the natural environment, including for example, power plant startup or shutdown, the sudden closure of valves in a pipeline system, passenger trains going through a railway tunnel, the blood flow in the human body and waves over a beach. Unsteady flow is also an intriguing topic of fundamental turbulence research since it reveals flow physics that is not always apparent in steady flows.

Our research aims at advancing the fundamental understanding of turbulence and wall shear stress in unsteady flows over rough as well as smooth surfaces, thereby underpinning the development of engineering models and flow control strategies.

The research involves numerical modelling and experimental work. DNS and RANS methodologies and computer codes have been developed which are used to perform simulations generating detailed data/information on the flow behaviours. These are complemented by experimental investigations performed in various large/sophisticated experimental facilities in several labs using LAD, PIV and hot-film anemometry. The new understanding is being implemented in the development of 1D unsteady friction models.

The flow pattern considered are accelerating, decelerating and pulsating flows. Two types of roughness as well as smooth surfaces will be studied.

Current project

Turbulence and wall shear stress in unsteady internal flows with rough surfaces (UFORCE) EPSRC, (EP/G068925/1), 2010-2013, Universities of Sheffield, Dundee and Aberdeen

Previous projects

  • Theoretical and experimental study of the dependence of transient pipe friction on turbulence dynamics, EPSRC (EP/C015177/1), 2006-2008.
  • Unsteady friction in pipes and ducts, EC Frame 6 (C29.30/H 4957 EU Hydralab), 2007-2008.