Turbulence is often said to be one of the last unsolved problems in classical physics. In the 20th century in turbulence studies, theory was the main driver, while the 21st century is marked by advances in experimental research. In this talk I will give a brief review of highlights in turbulence science. Then I will overview our experimental research on turbulence in fluid layers,
i.e. in fluids whose horizontal extent is much greater than their thickness, such as in the Earth’s atmosphere and oceans.
Turbulence in thin layers behaves as two-dimensional. The inverse energy cascade transfers energy from the small to larger scales and leads to spectral condensation of the turbulence energy at the box size. This fascinating ability of turbulence to self-organize into large coherent structures is responsible for a number of new effects. It appears that even in thick layers, when three-dimensional motions are present, turbulence may still be able to spectrally condense and generate large coherent vortices. Such vortices suppress vertical turbulent motions, impose twodimensionality, and reinforce their own energy supply.
This robust two-dimensionality of turbulence in layers which has recently been discovered by our group provides physics insight into the processes in the Sun interior (the so called solar tachocline) and has a potential to explain energy exchange in atmospheric winds.
ABOUT THE SPEAKER:
Dr Hua Xia obtained her PhD at the Australian National University in 2006. After completing her thesis on turbulence in magnetized plasma and fluids, she moved to fundamental research in fluid dynamics. Her current research interests include statistical methods in turbulence in fluid layers, nonlinear waves and surface wave turbulence.