Bernhard Simon

Dielectric Barrier Discharge Plasma Actuators for In-Flight Transition Delay

A single dielectric barrier discharge plasma actuator is employed for flow control on the pressure side of a natural laminar flow wing section under free-flight conditions. A full-sized motorized glider is equipped with the flow-control device and data-acquisition hardware to quantify the impact of the actuator on boundary-layer transition. A transition delay of approximately 3% chord is achieved, quantified by microphone and hot-wire measurements. Simultaneously, the influence of the variable ambient conditions on the flow-control performance is characterized. A closed-loop control algorithm enables constant actuator performance, despite varying humidity, temperature, and density throughout the test flights. The energy efficiency of the flow-control approach is estimated, providing a positive outlook for further improvements and a net benefit of transition control. Finally, a numerical procedure is presented to quantitatively estimate the effect of dielectric barrier discharge actuation on boundary-layer...

In-flight Transition Delay with DBD Plasma Actuators

A single dielectric barrier discharge plasma actuator is employed for flow control on the pressure side of a natural laminar flow wing section under free-flight conditions. A full sized motorized glider is equipped with the flow control device and data acquisition hardware to quantify the impact of the actuator on boundary-layer transition. A transition delay of approximately 3% chord is achieved, quantified by microphone and hot-wire measurements. Simultaneously, the influence of the variable ambient conditions on the flow control performance is characterized. A closed-loop control algorithm enables constant actuator performance, despite varying humidity, temperature and density throughout the test flights. The energy efficiency of the flow control approach is estimated, providing a positive outlook for further improvements and a net benefit of transition control.

IR Measurements for Quantification of Laminar Boundary Layer Stabilization with DBD Plasma Actuators

In-flight experiments for laminar boundary layer stabilization are conducted on a laminar flow wing glove, mounted on a manned motor glider. A single DBD plasma actuator is operated on the pressure side of the glove to delay natural laminar-turbulent transition while an infra red (IR) camera is mounted below the wing allowing a measurement of the spatial development of the transition. Besides the quantification of the flow control result, this article shows postprocessing strategies for perspective camera calibration with curved surfaces, image dewarping and for inhomogeneous surface heating.