Instability and sensitivity of the flow around a rotating circular cylinder
2010 (English)In: Journal of Fluid Mechanics, ISSN 0022-1120, E-ISSN 1469-7645, Vol. 650, 513-536 p.Article in journal (Refereed) Published
The two-dimensional flow around a rotating circular cylinder is studied at Re = 100. The instability mechanisms for the first and second shedding modes are analysed. The region in the flow with a role of 'wavemaker' in the excitation of the global instability is identified by considering the structural sensitivity of the unstable mode. This approach is compared with the analysis of the perturbation kinetic energy production, a classic approach in linear stability analysis. Multiple steady-state solutions are found at high rotation rates, explaining the quenching of the second shedding mode. Turning points in phase space are associated with the movement of the flow stagnation point. In addition, a method to examine which structural variation of the base flow has the largest impact on the instability features is proposed. This has relevant implications for the passive control of instabilities. Finally, numerical simulations of the flow are performed to verify that the structural sensitivity analysis is able to provide correct indications on where to position passive control devices, e.g. small obstacles, in order to suppress the shedding modes.
Place, publisher, year, edition, pages
2010. Vol. 650, 513-536 p.
Baseflows, Flow stagnation, Global instability, In-phase, Instability mechanisms, Numerical simulation, Passive control, Passive control devices, Rotating circular cylinders, Rotation rate, Shedding modes, Steady state solution, Structural sensitivity, Structural variations, Turning points, Two-dimensional flow, Unstable modes, Wavemakers, Circular cylinders, Computer simulation, Control, Groundwater flow, Linear stability analysis, Passive networks, Phase space methods, Rotation, Structural analysis, Wakes
Fluid Mechanics and Acoustics
IdentifiersURN: urn:nbn:se:kth:diva-27542DOI: 10.1017/S0022112009993764ISI: 000278212500021ScopusID: 2-s2.0-77952429216OAI: oai:DiVA.org:kth-27542DiVA: diva2:379212
QC 201012172010-12-172010-12-132010-12-17Bibliographically approved