Abstract

Turbulence is everywhere. Its length and timescales can range from the very large to the very small. It is strongly dissipative and diffusive, meaning that it is very effective at converting kinetic energy to heat and strongly enhances the transport and mixing of momentum, heat, chemicals and more. The smallest lengthscales of the motion are responsible for this dissipation and mixing, but making direct measurements can be very difficult owing to their small size and short timescales. We have improved upon a velocimetry technique that allows us to make accurate and spatially resolved measurements of the fine scales in three dimensions. This gives experimentalists a new ability to answer questions about the supposed universal behaviours of such motions that used to be confined to the land of direct numerical simulations. In this talk, I shall introduce the fundamentals of this technique and present some preliminary findings from a laboratory investigation of homogeneous, axisymmetric turbulence.