On the drag and shedding frequency of two-dimensional bluff bodies

Abstract

A semiempirical study is made of the bluff-body problem.Some experiments with interference elements in the wake close behind a cylinder demonstrate the need for considering that region in any complete theory.Dimensional analysis of a simple model of the region leads to a universal Stromal number S* which is then experimentally determined a s a function of wake Reynolds nuniber This result, together with free-streamline theory, allows the drag to be calculated from a measurement of the shedding frequency and furnishes a useful correlation between different bluff cylinders. R*.By allowing for some annihilation of the vorticity in the free shear l/ayys, it is shown how to corribine the free-streamline theory with Karman's theory of the vortex street to obtain a solution dependent on only one experimental measurement.hot-wire equipment, manometry, and so forth were employed.The work is part of a broader program of turbulence research directed by Dr. H. W.