Abstract
A phenomenon that the value of Strouhal number abruptly changes from 0.06 to 0.15 for rectangular cylinders with the width to height ratio of 5-6, in the range of high Reynolds numbers(Re-10 4 ) has been found by the use of a hot-wire technique. The change in flow pattern corresponding to the discontinuity of Strouhal number is confirmed by means of the visualization technique of a smoke-wire.
