Control of cylinder oscillations by plasma actuators

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

Poquerolles

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

CNRS

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 air 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 responses $f$ at high mass ratio of $m^* = m/m_d approx O(10^3)$, where $m$ is the system mass and $m_d$ is the displaced fluid (air) mass by the cylinder, over a range of reduce velocities, $U^* = U_infty/f_nD$, where $U_infty$ is the free stream velocity, $f_n$ is the transverse natural frequency of system measured in the still fluid, and $D$ the diameter of the cylinder. All the experience were focused on a Reynold´s number $Re approx 3cdot 10^{3}$. This scheme involves a Strouhal number $St approx 0.21 $ and $U^* sim 5$.We employed one dielectric barrier discharge (DBD) plasma actuator to modify the amplitude and frequency response of the system. The DBD plasma actuator was placed along the cylinder span and different angles respect to the oncoming flow were considered. The electrical parameter of control of the actuator was the burst mode frequency ($f_b$), which was tested around $f_n$. The others parameters of the plasma discharge were set in frequency $f_{plasma}sim 5kHz$, voltage $V_{pp}sim 6kV$ and duty cycle $DC=50%$.We have found that, within our experimental conditions, the plasma actuator could change the dynamics of the vortex shedding thus modifying the VIV phenomena.