Vortex Shedding (Flow Tank Version)

Wolfgang uses a pendulum partially immersed in a makeshift flow tank to show us the effect of vortex shedding on a small object.


When fluid flows around a cylindrical object, there is a range of flow velocities for which a von Karman vortex street is formed. The shedding of these vortices imparts a small, periodic force on the object. Here the object is a cylinder attached to a physical pendulum whose frequency of oscillation is adjustable. The end of the cylinder is submerged in flowing water. When the frequency of the pendulum is adjusted to match the frequency of vortex shedding, the cylinder swings transverse to the direction of flow with a peak-to-peak amplitude of a few centimeters.

Other Harvard demonstrations

Baths and Quarks

David Tong spends a lot of time in the bath. For him, this is work. Lying in the bath, he thinks about the problem that he has been working on for five years. It is a problem which has been troubling scientists for 40 years and which has a $1 million prize waiting for whoever is able to solve it.

 Professor David Tong, Department of Applied Mathematics and Theoretical Physics, University of Cambridge