Results of experimental investigations of vortex-shedding frequencies and surface pressures of circular and square cylinders with the same hydraulic diameter are described. Pressure measurements on circular and square cylinders and hot-film measurements in the wakes were conducted. The range of Reynolds numbers was 1.3 x 10(4)- 2 X 105, which is characterized as subcritical flow regimes. Also, to reveal the combined influence of Reynolds number and angle of incidence on the pressure and spectral density distributions of velocities, experiments were carried out on square and rectangular cylinders for the angle of incidence in the range 0less than or equal to alpha less than or equal to45 deg. At zero incidence, pressure coefficients on the front and side faces of the square cylinder change considerably with Reynolds number, whereas as the angle of incidence increases to 30 deg, the effect of the Reynolds number seems to diminish. Spectral density distributions in the wake and surface pressures depend on Reynolds number and the angle of incidence. The variations of the strength of the spectral densities with Reynolds number in the wakes of circular and square cylinders show different characteristics. Variations of spectral density distributions and vortex shedding with Reynolds number, geometric dimensions of models, and angle of incidence are presented. References: 39
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