# Fluid Dynamics

This group's research covers a wide spectrum of topics in fluid dynamics. It covers vortex dynamics and turbulence, including basic problems of the Navier-Stokes equations, differential geometric characterisation of Lagrangian stability and possible singularity formation in Euler flows. The group also has interests in engineering fluid dynamics, particularly in microfluidic rheology and in interfacial flows, including the Marangoni effect. Acoustic waves, e.g. digitised speech patterns, are also studied.

## Members

Academic staff | |||||
---|---|---|---|---|---|

Name | Office | Phone | VCard | ||

Dr Eun-jin Kim | H13 | 23876 | E.Kim | vcard | Fluid dynamics, magnetohydrodynamics (MHD), plasma physics, self-organisation, non-equilibrium statistical mechanics, turbulence, solar/stellar physics, magnetic fusion, homeostasis in biosystems |

Dr Yi Li | H14 | 23882 | YiLi | vcard | Fluid dynamics. Fluid flow optimization. Turbulence. Wind energy |

Prof Koji Ohkitani | G13 | 23861 | K.Ohkitani | vcard | Computational Fluid Dynamics |

Dr Julia Rees | H21 | 23782 | J.Rees | vcard | Microfluidics, Microbubble technology, Engineering fluid dynamics, Stratified flows |

Dr Ashley Willis | H12 | 23746 | A.P.Willis | vcard | Fluid dynamics, Magnetohydrodynamics (MHD) |

Research associates | |||||
---|---|---|---|---|---|

Name | Office | Phone | VCard | ||

Dr Stephen Chaffin | K10 | 23904 | S.Chaffin | vcard | Engineering fluid dynamics, bubbly flows, viscoelastic flows, CFD, asymptotics |

Dr Elena Marensi | G31 | 23825 | E.Marensi | vcard | Computational Fluid dynamics |

Dr Riccardo Vanon | G31 | 23825 | R.Vanon@sheffield.ac.uk | vcard |

Postgraduate students | |||||
---|---|---|---|---|---|

Name | Office | Phone | VCard | ||

Naseer Abdullah | J14a | NSAbdullah1 | vcard | ||

Sukaina AL-Bairmani | H25 | SAAL-Bairmani1 | vcard | ||

Ms Avan Al-Saffar | H25 | ASAl-Saffar1 | vcard |

## Current grants

Statistics of fluid turbulence and operational calculus | EPSRC |

Optimisation in fluid mechanics | EPSRC |

## Past grants

Microbubble Cloud Generation | EPSRC |

Efficient capture of the dominant periodic orbits underlying turbulent fluid flow |

## Key publications

- Kuhnen, J., et al. and Willis, A.P.

"Destabilizing turbulence in pipe flow"

Nature Physics (2018) - Guseva, A., Hollerbach, R., Willis, A.P. and Avila, M.

"Dynamo action in a quasi-Keplarian Taylor-Couette flow"

Physical Review Letters (2018) - Jianlei Zhang, Gang Dong and Li, Y.

"Algorithm for transient growth of perturbations in channel Poiseuille flow"

Applied Mathematics and Mechanics (2017) - Ohkitani, K.

"Analogue of the Cole-Hopf transform for the incompressible Navier–Stokes equations and its application"

Journal of Turbulence (2017) - Ohkitani, K.

"Characterization of blowup for the Navier-Stokes equations using vector potentials"

AIP Advances (2017) - Ohkitani, K.

"Cole–Hopf-Feynman–Kac formula and quasi-invariance for Navier–Stokes equations"

Journal of Physics A: Mathematical and Theoretical (2017) - Zimmerman, W.B. and Rees, J.M.

"Excitation of surface waves due to thermocapillary effects on a stably stratified fluid layer."

Applied Sciences (2017) - Ohkitani, K.

"Near-invariance under dynamic scaling for Navier–Stokes equations in critical spaces: a probabilistic approach to regularity problems"

Journal of Physics A: Mathematical and Theoretical (2017) - AL-Bairmani, and Li, Y.

"Subgrid-scale stresses and scalar fluxes constructed by the multi-scale turnover Lagrangian map"

Physics of Fluids (2017) - Duguet, Y., Omel'Chenko, O. and Wolfrum, M.

"Surfing the edge: using feedback control to find nonlinear solutions"

Journal of Fluid Mechanics (2017) - G S Regunath, W B Zimmerman and Rees, J.M.

"Dual plane PIV investigation of acoustically excited jets in a swirl nozzle."

Nonlinear Processes in Geophysics (2016) - Bashir, S., M Bashir, Rees, J.M. and W B Zimmerman

"Flow fields during formation of W/O and O/W emulsions using µPIV."

Journal of Biochips and Tissue Chips (2016) - N Abdulrazzaq, B H Al-Sabbagh, Rees, J.M. and W B Zimmerman

"Purification of bioethanol using microbubbles generated by fluidic oscillation: a dynamic evaporation model."

Industrial and Engineering Chemistry Research (2016) - Ohkitani, K.

"Study of the Navier–Stokes regularity problem with critical norms"

Fluid Dynamics Research (2016) - Ohkitani, K.

"Dynamical equations for the vector potential and the velocity potential in incompressible irrotational Euler flows: A refined Bernoulli theorem"

Physical Review E (2015) - Ohkitani, K.

"Late formation of singularities in solutions to the Navier–Stokes equations"

Journal of Physics A: Mathematical and Theoretical (2015) - N Abdulrazzaq, B H Al-Sabbagh, Rees, J.M. and W B Zimmerman

"Separation of azeotropic mixtures using air microbubbles generated by fluidic oscillation."

AIChE Journal (2015) - Li, Y.

"The evolution towards the rod-like axisymmetric structure for turbulent stress tensor"

Physics of Fluids (2015) - Kerswell, R.R., Willis, A.P. and Pringle, C.C.T.

"An optimization approach for analysing nonlinear stability with transition to turbulence in fluids as an exemplar"

Reports on Progress in Physics (2014) - Li, Y. and Carlos Rosales

"Constrained multi-scale turnover Lagrangian map for anisotropic synthetic turbulence: A priori tests"

Physics of Fluids (2014) - Chantry, M., Willis, A.P. and Kerswell, R.R.

"The genesis of streamwise-localized solutions from globally periodic traveling waves in pipe flow"

Physical Review Letters (2014) - Ohkitani, K. and Al Sulti, FAS

"Singularity formation in the Smirnov–Chukbar–Zaburdaev equation for the deformation of vortex lattices"

Journal of Physics A: Mathematical and Theoretical (2013) - Dowker, M.D and Ohkitani, K.

"Intermittency and local Reynolds number in Navier-Stokes turbulence: A cross-over scale in the Caffarelli-Kohn-Nirenberg integral"

Physics of Fluids (2012) - Ohkitani, K. and Dowker, M.D

"Numerical study on comparison of Navier-Stokes and Burgers equations"

Physics of Fluids (2012) - Al Sulti, FAS and Ohkitani, K.

"Vortex merger and topological changes in two-dimensional turbulence"

Physical Review E (2012) - Zimmerman, W.B., Rees, J.M. and Hewakandamby, B.N.

"Numerical analysis of solutocapillary Marangoni-induced interfacial waves"

Advances in Colloid and Interface Science (2007) - Zimmerman, W., Rees, J.M. and Craven, T.

"Rheometry of non-Newtonian electrokinetic flow in a microchannel T-junction"

Microfluidics and Nanofluidics (2006) - Zimmerman, W.B. and Rees, J.M.

"Long solitary internal waves in stable stratifications"

Nonlinear Processes in Geophysics (2004) - Mole, N.

"The large time behaviour in a model for concentration fluctuations in turbulent dispersion"

Atmospheric Environment (2001)