Influence of turbulence intensity on vortex pattern for a rigid cylinder with turbulence stimulation in flow induced oscillations

Journal Article · 16 August 2021 · Ocean Engineering

DOI: https://doi.org/10.1016/j.oceaneng.2021.109349 · OSTI ID:1977521

Zhang, Dahai ^[1]; Wang, Wenhao ^[2]; Sun, Hai ^[3]; Bernitsas, Michael M. ^[4]

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1. China University of Petroleum, Qingdao (China); University of Michigan, Ann Arbor, MI (United States); OSTI
2. China University of Petroleum, Qingdao (China); Kunming Shipborne Equipment Research & Test Center (China)
3. University of Michigan, Ann Arbor, MI (United States); Harbin Engineering University (China)
4. University of Michigan, Ann Arbor, MI (United States); Vortex Hydro Energy, Inc., Ann Arbor, MI (United States)

The effect of ambient turbulence intensity on the flow induced oscillations of rigid circular cylinders with symmetric and asymmetric local turbulence stimulation is studied. Cylinders oscillate in one degree of freedom transversely to a steady uniform flow. Two-dimensional unsteady Reynolds-Average Navier-Stokes equations with the Spalart-Allmaras turbulence model are used to solve the problem numerically. Three freestream turbulence intensity values (0.2%, 1%, 5%) are used to study the influence of turbulence intensity on vortex pattern. Simulation results are compared with experimental data measured in the Marine Renewable Energy Laboratory of the University of Michigan in the range of 30,000 ≤ Re ≤ 110,000. The amplitude ratio, lift coefficient, vortex modes, and the interactions between vortices and cylinders are observed and discussed. In conclusion, major conclusions are: (a) Vortex patterns strongly depend on the freestream ambient turbulence intensity. (b) Low turbulence intensity can generate multi-vortex patterns at high Re. (c) High turbulence intensity results in fewer separations of a shed vortex into multiple vortices inducing emergence of elongated vortex patterns.

• Research Organization: Vortex Hydro Energy, Inc., Ann Arbor, MI (United States)
• Sponsoring Organization: Natural Science Foundation of Shandong Province of China; USDOE Office of Energy Efficiency and Renewable Energy (EERE)
• Grant/Contract Number: EE0006780
• OSTI ID: 1977521
• Journal Information: Ocean Engineering, Journal Name: Ocean Engineering Journal Issue: C Vol. 237; ISSN 0029-8018
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English