Our recent wing wake research, described in another page, has influenced our recent interpretations of two modes of instability in bluff body wake vortices, which I first observed in a paper in 1988 at Caltech (which have become known since that time in the literature as "Modes A and B"). Each mode has a characteristic wavelength AND frequency, as well as a distinct vortical form, and origin.

A breakthough on this research is our understanding that the two distinct modes represent what are known as “elliptic” and “hyperbolic” instabilities, and we are extending this work by conducting extremely sensitive (and quite subtle) computational studies. This is really a collaboration between Cornell (Williamson), Marseille (Thomas Leweke), and Melbourne (Mark Thompson)!

"Three-dimensional instabilities in wake transition"
Leweke & Williamson (1998) European Journal of Mechanics B-Fluids.

"The physical mechanism of transition in bluff body wakes"
Thompson, Leweke & Williamson (2001) Journal of Fluids and Strcutures.

After the 8 years of extensive research on the subject of vortex dynamics in wakes, which was triggered by our breakthrough papers in 1988, I was invited by the Scientific Committee of Annual Reviews to write a review article for this area of research. It is a review of the international results over the last 25 years, but also will give a good summary of all of our own research in this field.

"Vortex dynamics in the cylinder wake"
Williamson (1996) Annual Review of Fluids Mechanics.

Further key papers in our research program relating to wakes are:

Williamson (1989) JFM

Williamson (1988) Transition 3D Physics of fluids

A very fruitful collaboration between our team and Peter Monkewitz of EPFL, Switzerland, resulted in work where we were able to control three-dimensional patterns of vortex shedding, and even to make them dance to music.

"Phase dynamics of Kármán vortices in cylinder wakes"
Monkewitz, Williamson and Miller (1996)