The human ear can typically hear frequencies between 20 Hz and 20 kHz. Find the ranges of fluid velocities over which you would expect to hear vortices being shed from i) a 3 mm diameter telephone wire in air and ii) a 1 m diameter wooden post in the ocean. For these cases, find the minimum fluid speed below which no vortices would be shed.

Contributed by Stavros Tavoularis, Department of Mechanical Engineering, University of Ottawa, Ottawa, Canada.