School of Architecture, Building and Civil Engineering

Staff

Dr Chris Keylock PhD (Cantab), MSc (British Columbia), MA (Oxon)

Photo of Dr Chris Keylock

Professor of Fluid Mechanics

Chris joined Loughborough in May 2018 having previously held lecturer and senior lecturer positions at the universities of Sheffield (2010-2018) and Leeds (2000-2010). In 1997 he worked on snow avalanche risk assessment at the Icelandic Meteorological Office. He has studied at the Universities of Oxford (1991-1994), British Columbia (1994-1996), and Cambridge (1997-2002). For the 2016-2017 academic year he held a Royal Academy of Engineering/Leverhulme Trust Senior Research Fellowship, for which he was based at the Department of Mechanical Engineering, Johns Hopkins University and the Department of Aeronautics, Imperial College London.

My research intersects a number of areas including fluid mechanics, geophysics, geomorphology, hydrology and nonlinear signal processing. I began my career working on snow avalanche risk assessment and while I still retain an interest in this area, contemporary research is more closely linked to fundamental fluid mechanics, fluids engineering and signal analysis. My primary contributions in these areas include:

 

Fluid Mechanics

  • Work on the modulation of small scale structures by larger events in turbulent boundary-layers (work with Melbourne and Southampton);
  • Properties of turbulent wakes when turbulence production and dissipation are not in equilibrium (work with Nagoya);
  • Work deriving new quantities for analysis from the velocity gradient tensor with a view to improving turbulence closure models.

 

Fluids Engineering

  • The development of a method (the velocity-intermittency quadrant technique) for extracting flow structure information from single-point instrumentation. This can successfully distinguish between canonical turbulent flows and has been applied to studying flow over bed-forms, in particular (work with Nagoya, Oldenburg, UC Irvine, Central Florida, Simon Fraser);
  • Use of an octant sequencing technique to demonstrate the importance of coherent flow structures for Reynolds stress budgets, impulse integral timescales and sediment entrainment (work with Cambridge and Lausanne).

 

Signal Analysis

  • An algorithm that preserves the original values of a time series or an image, and their multifractal properties. This has been applied to the analysis of turbulent flows and a generalization of it has been used for examining the log-returns for major financial indices;
  • A technique called Gradual wavelet reconstruction which provides synthetic data for hypothesis testing about a nonlinear signal. Using this technique and working with colleagues in Oldenburg, we have shown the smaller terms in a model for the turbulence velocity increments are significantly different to zero and play an important part in the dynamics. The method has also been used for deriving flooding confidence limits, understanding bed-form morphology (working with UC Irvine and Central Florida), and placing confidence limits on the effect flow structures have on the generation of bed shear stresses in turbulent flows (with Cambridge and Lausanne).  

Recent Publications:

Keylock, C.J. 2018. Gradual multifractal reconstruction of time-series: Formulation of the method and an application to the coupling between stock market indices and their Hölder exponents, Physica D 368, 1-9.

Keylock, C.J. 2017. Synthetic velocity gradient tensors and the identification of significant aspects of the structure of turbulence, Physical Review Fluids 2, 8, 084607.

Keylock, C.J. 2017. Multifractal surrogate-data generation algorithm that preserves pointwise Hölder regularity structure, with initial applications to turbulence, Physical Review E 95, 032123.

Higham, J.E., Brevis, W., Keylock, C.J., Safarzadeh, A. 2017. Using modal decompositions to explain the sudden expansion of the mixing layer in the wake of a groyne in a shallow flow, Advances in Water Resources 107, 451-459.

Keylock, C.J., Chang, K.S., Constantinescu, G.S. 2016. Large eddy simulation of the velocity-intermittency structure for flow over a field of symmetric dunes, Journal of Fluid Mechanics 805, 656-685.

Higham, J., Brevis, W., Keylock, C.J. 2016. A rapid non-iterative proper orthogonal decomposition based outlier detection and correction for PIV data, Measurement Science and Technology 27, no. 125303, doi: 10.1088/0957-0233/27/12/125303.

 

Selected Publications:

Invited Paper for the 50th anniversary special issue of Water Resources Research:

Keylock, C.J. 2015. Flow resistance in natural, turbulent channel flows: The need for a fluvial fluid mechanics, Water Resources Research 51, doi: 10.1002/2015WR016989.

 

Winner of the Tenth Fluid Dynamics Research Prize:

Keylock, C.J., Ganapathisubramani, B., Monty, J., Hutchins, N. and Marusic, I. 2016. The coupling between inner and outer scales in a zero pressure boundary layer evaluated using a Hölder exponent framework, Fluid Dynamics Research 48, 2, 021405.

 

Fluid Mechanics

Keylock, C.J. 2017. Synthetic velocity gradient tensors and the identification of significant aspects of the structure of turbulence, Physical Review Fluids 2, 8, 084607.

Keylock, C.J., Stresing, R. and Peinke, J. 2015. Gradual wavelet reconstruction of the velocity increments for turbulent wakes, Physics of Fluids 27, 025104.

 

Hydrodynamics

Keylock, C.J., Chang, K.S., Constantinescu, G.S. 2016. Large eddy simulation of the velocity-intermittency structure for flow over a field of symmetric dunes, Journal of Fluid Mechanics 805, 656-685.

Keylock, C.J., Lane, S.N., Richards, K.S. 2014. Quadrant/octant sequencing and the role of coherent structures in bed load sediment entrainment, Journal of Geophysical Research 119, 264-286, doi: 10.1002/2012JF002698.

 

Nonlinear Analysis

Keylock, C.J. 2017. Multifractal surrogate-data generation algorithm that preserves pointwise Hölder regularity structure, with initial applications to turbulence, Physical Review E 95, 032123.

Keylock, C.J. 2010. Characterizing the structure of nonlinear systems using gradual wavelet reconstruction, Nonlinear Processes in Geophysics 17, 615-632.

 

Snow Avalanche Research

Vriend, N.M., McElwaine, J.N., Sovilla, B., Keylock, C.J., Ash, M., Brennan, P.V. 2013. High resolution radar measurements of snow avalanches, Geophysical Research Letters 40, 1-5, doi:10.1002/grl.50134.

Keylock, C.J. and Barbolini, M. 2001. Snow avalanche impact pressure - vulnerability relations for use in risk assessment, Canadian Geotechnical Journal 37, 227-238.

Keylock C.J., McClung D.M. and Magnusson M.M. 1999. Avalanche risk by simulation, Journal of Glaciology 45, 303-314.

  • University of Cambridge
  • Duke University
  • Imperial College London
  • University of California, Irvine
  • University of Central Florida
  • Massachusetts Institute of Technology
  • University of Melbourne
  • University of Western Australia
  • 2013-present, Associate Editor, Water Resources Research
  • 2016-present, Member of the American Geophysical Union Joint Technical Committee on Hydroclimatic Hazards
  • 2017-present, Co-lead of the EPSRC UK Fluids Network Special Interest Group on Nonequilibrium Turbulence (www.nonequilibrium-turbulence.org.uk).