Turbulence remains surely the greatest unsolved problem in classical physics. I'm fascinated by its complexity and exquisite beauty, and I want to maximise what can be extracted from it, both in terms of scientific understanding and technological application. One of its most important features is its extraordinary ability to mix things together. Remarkable non-linear processes conspire to accelerate mixing by factors of billions, and we have yet to fully understand how they work, or to exploit their efficiency.

I'm also interested in self-organisation in fluids. Waves form ordered and predictable signals, whereas turbulence is incoherent and apparently disordered, though by no means random. Yet both may co-exist and interact in a fluid system. The path from order to disorder is familiar, eg. waves breaking on a beach, and though the converse is much less intuitive, it is still present in common engineering problems, eg. acoustic signals radiating from high speed jets. Even at low speeds waves can radiate from turbulent sources, if the reference frame is rotating, or where the ambient fluid has variations in density like the ocean.

So why is any of this useful to understand? We might want to reduce the noise that aircraft make, for instance. We might want to pinpoint unexpected noise sources. We might need to know very precisely how much mixing takes place during a process, to ensure for example that A+B doesn't go bang, or that exactly the right dose of a drug B gets to a patient. Mixing might also save the planet. No really: oceanic circulation is driven by salinity migration and heat transport, both of which are regulated by mixing processes. If saline mixing near the north pole were to cease entirely, there would be no net return flow balancing the warm Gulf Stream.

So what should you do if you are a keen to become a researcher that saves the planet, or are interested in any of my other research themes? Email me at [email protected].

• molecular processes in fluids
  • mixing
  • non-newtonian stress-strain
  • viscous 2D turbulence
• waves
  • acoustic propagation from turbulence
  • stability of oceanic internal waves
  • inertial waves in rotating turbulence
• nonlinearity
  • nonlinear inverse problems
  • multi-objective optimisation
  • smart image processing
• computational engineering
  • language design for parallel programming
  • developing novel numerical methods
  • new approaches to turbulence modelling
• experiments
  • new optical diagnostics
  • gravity-driven instabilities
  • momentum jets influenced by rotation