Turbulence in fluids is one of the most common phenomena of nature occurring on scales ranging from your ordinary teacup to swirling gas nebulae of galactic proportions. Our goal is to investigate this common, yet so-far poorly understood, behavior in an uncommon medium: superfluid helium whose flow is strongly influenced by quantum mechanical properties.
There are many possible approaches to experimental studies of turbulence. The one employed in this project is a staple of classical turbulence research: decaying turbulence is probed in the wake of a uniform grid, which, in our case, is towed through a square channel. We visualize the flow using fluorescence of metastable Helium molecules, a novel technique recently developed in this laboratory. Using this technique we are able to extract information on velocity (of the normal component of superfluid Helium) on a range of scales and decay times. The obtained information allows, among other things, study various statistical properties of the flow.