Control of cylinder oscillations by plasma actuators

F CASTRO; J. D'ADAMO; R SOSA; G ARTANA

Porquerolles

Workshop; HELIX 2015: Fluid-Structure Interactions and Vortex Dynamics in Aerodynamics; 2015

In this work we explore the ability of plasma actuators to control the vortex induced vibration (VIV) of a circular cylinder. The cylinder was mounted in a closed loop wind tunnel and linear oscillatory movement of the cylinder transverse to the free stream was allowed. We characterized the vibration amplitude A and frequency f responses at high mass ratio of m* = m/md, where m is the system mass and md is the displaced fluid (air) mass by the cylinder. We explored a range of reduced velocities, U* = U/fn.D, where U is the free stream velocity, fn is the transverse natural frequency of system measured in still fluid, and D the diameter of the cylinder. All the experiences were focused on a Reynolds number Re = 1000. This scheme involves a Strouhal number St = 0.21and U* = 4.8. We employed one dielectric barrier discharge (DBD) plasma actuator to modify the oscillations amplitude and frequency response of the system. The DBD plasma actuator was placed along the cylinder span. The electrical parameter of control of the actuator was the burst mode frequency (fb), which was tested around fn. The others parameters of the plasma discharge were fixed in frequencyfplasma = 4.6kHz, voltage Vpp = 6.5kV and duty cycle DC = 50%.We have found that, within our experimental conditions, the plasma actuator can change the dynamics of the vortex shedding thus modifying the VIV phenomena.