Advances in the control of wakes behind an in-line oscillating cylinder

The methods of base blowing, splitter-plate and small strip-element are used to suppress vortex shedding from a circular cylinder oscillating in line with an on-coming uniform stream. The non-lock-on mode and three lock-on modes of vortex shedding are found in the test ranges of Reynolds number and cylinder oscillation frequency. Wind tunnel experiment results show that, the base blowing is effective for all the modes of vortex suppression, the strip element is effective for the non-lock-on and two lock-on modes, and splitter plate for only the non-lock-on and one lock-on modes. The effective zones for every method are found out at different flow and oscillation conditions, the reductions of mean drag and fluctuating lift are investigated, and the control mechanism is discussed.