Graduate Student: Geoffrey Slipher, M.S. Candidate, University of Mareyland
Research Project:Electroactive Polymer Synthetic Jet Actuators ("EJETs") for Low Speed Active Flow Control
University Advisor: Dr. James E. Hubbard, Jr., Aerospace Engineering, University of Maryland
The multidisciplinary field of active flow control holds the near-term promise of significantly increasing the aerodynamic efficiency of vehicles by as much as 20% at highway speeds, thus improving their energy efficiency,
increasing fuel economy, and reducing emissions. One means of achieving
active flow control utilizes synthetic jets (SJs), which work by injecting energy into fluid flow fields through the cyclic transfer of fluid momentum.
The objective of the ongoing research is to develop and characterize a SJ actuation method that meets four critical requirements for implementation:
1) that it is inexpensive, 2) that it is lightweight, 3) that it is mechanically simple, and 4) that it operates efficiently in low speed applications such as automobiles at highway speeds. There has been no actuation method developed to date that meets all four requirements.
However, initial theoretical and experimental results show that resonating EAP membranes as the SJ actuation method can meet the requirements. The actuation method utilizes a pre-strained dielectric elastomer membrane excited to operate at resonance by the periodic application of Maxwell stress introduced through compliant electrodes. Attainable nozzle velocity at the synthetic jet exit has been experimentally determined to be greater than 25 m/s at an actuation frequency of 200 Hz with a maximum power consumption of about 0.3 Watts per actuator for a nozzle area of 1.6 square centimeters. This actuation method is particularly promising in automobiles due to the potentially large net benefit to society, but can also be applied to manned or unmanned aircraft flying at relatively low speeds (i.e. less than 200 knots). This ongoing research focuses on modeling, development, testing, and refinement of EJET hardware and a robust control scheme.
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