Journal of Fluid Mechanics


Mechanics of inhomogeneous turbulence and interfacial layers

J. C. R. HUNT a1, I. EAMES a2 and J. WESTERWEEL a3
a1 Department of Earth Sciences, University College London, Gower Street, London, WC1E 6BT, UK
a2 Departments of Mechanical Engineering and Mathematics, University College London, Torrington Place, London, WC1E 7JE, UK
a3 J. H. Burgers Centre, Delft University of Technology, Leeghwaterstraat 21, 2628 CA Delft, The Netherlands

Article author query
hunt jc   [Google Scholar] 
eames i   [Google Scholar] 
westerweel j   [Google Scholar] 


The mechanics of inhomogeneous turbulence in and adjacent to interfacial layers bounding turbulent and non-turbulent regions are analysed. Different mechanisms are identified according to the straining by the turbulent eddies in relation to the strength of the mean shear adjacent to, or across, the interfacial layer. How the turbulence is initiated and the topology of the region of turbulence are also significant factors. Specifically the cases of a layer of turbulence bounded on one, or two, sides by a uniform and/or shearing flow, and a circular region of a rotating turbulent vortex are considered and discussed.

The entrainment processes at fluctuating interfaces occur both at the outer edges of turbulent shear layers, with and without free-stream turbulence (e.g. jets, wakes and boundary layers), at internal boundaries such as those at the outside of the non-turbulent core of swirling flows (e.g. the ‘eye-wall’ of a hurricane) or at the top of the viscous sublayer and roughness elements in turbulent boundary layers. Conditionally sampled data enables these concepts to be tested. These concepts lead to physically based estimates for critical modelling parameters such as eddy viscosity near interfaces, entrainment rates, maximum velocity and displacement heights.

(Published Online April 24 2006)
(Received July 10 2005)
(Revised January 31 2006)