Flow instability, modelling and control


The SIG specialises in fluid flow transition and control: hydrodynamic stability, coherent structures and nonlinear dynamics, modelling, simulation, experiments and control strategies. The SIG aims at facilitating communication and collaboration for emerging challenges, training of next-generation researchers, and an increased international visibility of the UK’s research activities in this area.

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L = leader; C = co-leader; * = Other key personnel

[L]  Yongyun Hwang (Imperial College London): y.hwang@imperial.ac.uk
[C]  Ati Sharma (University of Southampton): a.sharma@soton.ac.uk
Paolo Adami (Rolls-Royce)
Anurag Agarwal (University of Cambridge)
Evangelia Antonopoulou (University of Leeds)
Richard Ashworth (Airbus)
Chris Atkin (City University)
Dwight Barkley (University of Warwick)
Andrea Cassinelli (Imperial College London)
Colm-cille Caulfield (University of Cambridge)
Sergei Chernyshenko (Imperial College London)
Stephen Cowley (University of Cambridge)
John Craske (Imperial College London)
David Dennis (University of Liverpool)
Bharath Ganapathisubramani (University of Southampton)
Stephen Garrett (University of Leicester)
Mike Gaster (City University)
Jonathan Healey (Keele University)
Richard Hewitt (University of Manchester)
Julien Hoessler (McLaren)
Zahir Hussain (Manchester Metropolitan University)
Matthew Juniper (University of Cambridge)
Richard Kerswell (University of Cambridge)
Davide Lasagna (University of Southampton)
Rebecca Lingwood (Brunel University London)
Rob Long (University of Leeds)
Xuerui Mao (University of Nottingham)
Nick Martin (Northumbria University)
Andrew McMullan (University of Leicester)
Jonathan Morrison (Imperial College London)
George Papadakis (Imperial College London)
Nigel Peake (University of Cambridge)
Pierre Ricco (University of Sheffield)
Anatoly Ruban (Imperial College London)
Neil Sandham (University of Southampton)
Shahrokh Shahpar (Rolls-Royce)
Spencer Sherwin (Imperial College London)
Frank Smith (University College London)
Steve Tobias (University of Leeds)
Owen Tutty (University of Southampton)
Christina Vanderwel (University of Southampton)
Ashley Willis (University of Sheffield)
Xuesong Wu (Imperial College London)

Scope of SIG

The SIG specialises in fluid flow transition and control, areas that the UK has maintained world-class research for many years. The topics of the SIG include hydrodynamic stability, transition to turbulence, coherent structures and nonlinear dynamics, model reduction, simulations, experiments, and development of novel flow control strategies.

The SIG members consist of leading figures in established (flow instability) and emerging areas (dynamical systems, flow control, optimisation) from both academia and industry (Airbus, Rolls-Royce & Mclaren), and their expertise covers all the technical aspects (theory, computation and experiments).  The scope of the SIG is:

1) to improve communication across boundaries between traditional and emerging areas;

2) to foster the next generation of academics and industrial researchers at the subject interface;

3) to collectively correspond to research council funding initiatives;

4) to increase international visibility of the UK’s research activities in the areas of the SIG.


EPSRC Summer School on Modal Decompositions in Fluid Mechanics


Fluid mechanics is, like many other fields, enjoying an ever increasing access to huge data sets gathered from experiments, observations in the field or just DNS-generated flow solutions on supercomputers. This data flood has started to fundamentally change the modern research landscape from ‘theory-driven’ to ‘data-driven’. The scope of this EPSRC–funded, UK Fluid Network summer school is to provide training in the state-of-the-art modern research tools applicable to this data revolution for PhD students and postdoctoral researchers in the UK. Four days of lectures and tutorials will be delivered by the world-leading experts in each area.



5-8, August, 2019, Department of Applied Mathematics and Theoretical Physics (DAMTP), University of Cambridge



- Proper orthogonal decomposition and its variants

- Model reductions for hydrodynamic instabilities

- Dynamic mode decomposition

- Koopman mode decomposition

- Resolvent mode analysis

- Exact coherent states, periodic orbits and state-space visualisations


Confirmed invited lecturers

Tim Colonius (Caltech)

Shervin Bagheri (KTH, Stockholm)

Peter Schmid (Imperial)

Steven Brunton (Univ. Washington)

Beverley McKeon (Caltech)

Ati Sharma (Southampton)

Rich Kerswell (Cambridge)

Ashley Willis (Sheffield)


School booklet (download)


Lecture schedule & notes

5th Afternoon: Tim Colonius (lecture note; further readings; excercise; programme)

6th Morning: Rich Kerswell (lecture note 1, lecture note 2, Slides) / Ashley Willis (lecture note)

6th Afternoon: Beverley McKeon (lecture note) / Ati Sharma (lecture note, worksheet, tutorial code)

7th Morning: Shervin Bagheri (lecture note; tutorial codes

7th Afternoon: Steven Brunton (lecture note)

8th Morning: Peter Schmid (lecture note; tutorial codes)



Yongyun Hwang (Imperial)

Rich Kerswell (Cambridge)

Ati Sharma (Southampton)



The application result and the registration process have been informed on 17th of May.

We do not accept any more registrations. 



Yongyun Hwang (y.hwang@imperial.ac.uk)



Upcoming Meetings

11th International Symposium on Turbulent Shear Flow Phenomena - 30, July - 2, August 2019, Grand Harbour Hotel, Southampton, UK

IUTAM Symposium on Transition - 2-6 September 2019 - Imperial College, London, UK.



Previous Meetings

SIG Meeting - 28th August 2018 - Imperial College, London, UK (Programme)

Euromech Colloquium 598 - 29th/31st August 2018 - Imperial College, London, UK.

1st SIG Meeting - 28th/30th March 2017 - University of Southampton, UK (Abstract)



Beer J., Tobias S.M. & Weiss N.O. 2018, On long-term modulation of the Sun’s magnetic cycleMonthly Notices of the Royal Astronomical Society, 473, pp. 1596–1602.

Ghirardo G., Juniper M.P. & Bothien M.R. 2018, The effect of the flame phase on thermoacoustic instabilities, Combustion and Flame187, pp. 165-184.

Goldstein M.E. & Ricco P. 2018, Non-localized instabilities resulting from leading-edge receptivity at moderate supersonic Mach numbers, Journal of Fluid Mechanics848, pp. 435-477.

Kuhnen J., Song B., Scarselli D., Budanur, N.B., Riedl M., Willis A.P., Avila M. & Hof B. 2018, Destabilizing turbulence in pipe flow, Nature Physics, ISSN 1745-2473.

Yang Q., Willis A.P. &; Hwang, Y. 2018, Energy production and self-sustained turbulence at the Kolmogorov scale in Couette flow. Journal of Fluid Mechanics834, pp. 531-554.

Aguilar J.G., Magri L. & Juniper M.P. 2017, Adjoint-based sensitivity analysis of low-order
thermoacoustic networks using a wave-based approach
, Journal of Computational Physics
341, pp. 163-181.

Al-Tameemi W.T.M. & Ricco P. 2017, Pattern-based pressure drop of air-water flow across a 90 sharp miter elbow, International Journal of Computational Methods and Experimental Measures6, pp. 198-207.

Budanur N.B., Short K.Y, Farazmand M., Willis A.P. & Cvitanović, P. 2017, Periodic orbits form the backbone of turbulent pipe flowJournal of Fluid Mechanics, 833, pp. 274-301.

Calkins M.A., Julien K. & Tobias S.M. 2017 Inertia-less convectively-driven dynamo models in the limit of low Rossby number and large Prandtl number, Physics of the Earth and Planetary Interiors, 266, pp. 54-59.

Cassinelli A., de Giovanetti M. & Hwang Y. 2017, Streak instability in near-wall turbulence revisited, Journal of Turbulence, 18, pp. 443-464.

Cossu C. & Hwang Y. 2017, Self-sustaining process at all scales in wall-bounded turbulent shear flows, Philosophical Transactions of the Royal Society A, 375, 20160088. 

Craske J. 2017, The properties of integral models for planar and axisymmetric unsteady jets, IMA Journal of Applied Mathematics82, pp. 305-333.

Craske J., Salizzoni P. & van Reeuwijk M. 2017, The turbulent Prandtl number in a pure plume is 3/5Journal of Fluid Mechanics, 822, pp. 774-790.

Deng J., Xue J., Mao X. & Caulfield C. 2017, Coherent structures in interacting vortex rings, Physical Review Fluids, 2, 022701.

de Giovanetti M., Sung H.J. & Hwang Y. 2017, Streak instability in turbulent channel flow: a seeding mechanism of large-scale motions, Journal of Fluid Mechanics, 832, pp. 483-513.

Griffiths P.T., Garrett S.J., Stephen S.O. & Hussain Z. 2017, Quantifying non-Newtonian effects in rotating boundary-layer flows, European Journal of Mechanics B/Fluids, 61, pp. 304-309.

Grimble T., Agarwal A. & Juniper M.P. 2017, Local linear stability analysis of cyclone separatorsJournal of Fluid Mechanics, 816, pp. 507-538.

Guseva A., Hollerbach R., Willis A.P. & Avila M. 2017, Azimuthal magnetorotational instability at low and high magnetic Prandtl numbers, Magnetohydrodynamics, 53, pp. 25-34.

Guseva A., Hollerbach R., Willis A.P. & Avila M. 2017, Dynamo action in a quasi-Keplarian Taylor-Couette flow, Physical Review Letters, 119, 164501.

Guseva A., Willis A.P., Hollerbach R. & Avila M. 2017, Transport properties of the azimuthal magnetorotational instabilityThe Astrophysical Journal, 849, 92.

Hussain Z. 2017, Competing instabilities of rotating boundary-layer flows in an axial free-streamEuropean Journal of Mechanics B/Fluids, 61, pp. 316-320.

Jamieson N. & Juniper M.P. 2017, Experimental sensitivity analysis of a linearly stable thermoacoustic system via a pulsed forcing technique, Experiments in Fluids, 58, pp. 123-134.

Jamieson N., Rigas G. & Juniper M.P. 2017, Experimental sensitivity analysis via a secondary heat source in an oscillating thermoacoustic system, International Journal of Spray and Combustion Dynamics, 9, pp. 230-240.

Kent T., Bokhove O. & Tobias S. 2017, Dynamics of an idealized fluid model for investigating convective-scale data assimilation. Tellus A: Dynamic Meteorology and Oceanography, 69, 1369332. 

Mao X. & Hussain F. 2017, Optimal transient growth on a vortex ring and its transition via cascade of ringlets, Journal of Fluid Mechanics, 832, pp. 269-286.

Mao X., Zaki T., Sherwin S. & Blackburn H. 2017, Transition induced by linear and nonlinear perturbation growth in flow past a blade, Journal of Fluid Mechanics820, pp. 604-632.

Marensi E. & Ricco P. 2017, Growth and wall-transpiration control of nonlinear unsteady Gortler vortices forced by free-stream vortical disturbances, Physics of Fluids, 29 114106.

Marensi E., Ricco P. & Wu X. 2017 Nonlinear unsteady streaks engendered by the interaction of free-stream vorticity with a compressible boundary layer, Journal of Fluid Mechanics, 817, pp. 80-121.

Márquez-Artavia X., Jones C.A. & Tobias S.M. 2017, Rotating magnetic shallow water waves and instabilities in a sphereGeophysical and Astrophysical Fluid Dynamics, 111 (4), pp. 282-322.

Nigro G., Pongkitiwanichakul P., Cattaneo F. & Tobias S.M. 2017, What is a large-scale dynamo?Monthly Notices of the Royal Astronomical Society, 464, pp. L119-L123.

Semlitsch B., Orchini A., Dowling A.P. & Juniper M.P. 2017, G-equation modelling of thermo-acoustic oscillations of partially-premixed flames, International Journal of Spray and Combustion Dynamics4, pp. 260-276.

Sharma A.S., Moarref R. & McKeon B.J. 2017, Scaling and interaction of self-similar modes in models of high-Reynolds number wall turbulencePhilosophical Transactions of the Royal Society A, 375(2089).

Sharma A.S., Theofilis V. & Colonius T. 2017, Special issue on global flow instability and controlTheoretical and Computational Fluid Dynamics, 31, pp. 471-474.

Tobias S.M. & Marston J.B. 2017, Direct statistical simulation of jets and vortices in 2D flows. Physics of Fluids, 29, 111111. 

Tobias S.M. & Marston J.B. 2017, Three-dimensional rotating Couette flow via the generalised quasilinear approximationJournal of Fluid Mechanics, 810 , pp. 412-428.

Wen C., Poole R.J., Willis A.P. & Dennis D.J.C. 2017, Experimental evidence of symmetry-breaking supercritical transition in pipe flow of shear-thinning fluidsPhysical Review Fluids, 2, 031901.

Willis A.P. 2017, The Openpipeflow Navier-Stokes Solver, SoftwareX, 6, pp.124-127.

Willis A.P., Duguet Y., Omel'chenko O. & Wolfrum M. 2017, Surfing the edge: using feedback control to find nonlinear solutions, Journal of Fluid Mechanics, 831, pp. 579-591.


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