On the Force and Vortex Shedding on a Circular Cylinder from Subcritical up to Transcritical Reynolds Numbers

Abstract

Pressure distributions and vortex shedding were measured in a cryogenic wind tunnel from subcritical up to transcritical Reynolds numbers (10⁵ ≤ R_e ≤ 10⁷) and Mach numbers up to 0.3 without changing experimental arrangement. Drag coefficients were calculated using pressure distributions. Pressure distributions and drag coefficients show characteristic changes for subcritical, lower transition, critical, upper transition and transcritical Reynolds numbers respectively. Strouhal number is constant in the range of Reynolds numbers 10⁵ ≤ R_e ≤ 3.2 ×10⁵. Narrow band vortex shedding could not be found in the critical Reynolds numbers range (3.2×10⁵ ≤ R_e ≤6.9×10⁵), but it was found again in the upper transition and transcritical Reynolds number ranges. The pressure distributions and spectra of velocity fluctuations are presented for several characteristic values of Reynolds numbers. Results are also compared with those of other authors.