Fluid flows are fascinating to observe.  Most of the flows are unstable and create random or periodic structures.  When these flows interact with a pressure field, sound is the result.   When the Reynolds number is not too large (that is, when the instability of the flow is not too strong), and when the fluid motion is confined to two dimensions, we can observe the dance of isolated vortices.   Such vortices can also be observed in boundary layers,  and around windmills, and they even survive in full three-dimensional turbulence. 

 Most movies have been shot in our laboratory.

 

 

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