Micron size dielectric barrier discharge actuators, designed for minimal footprint area and weight penalty, show a wall jet up to 2.0 m/s consuming 15 W/m of electrode. A torsional balance measures force up to 3 mN/m of electrode and demonstrates equivalent “thrust effectiveness” (induced force/power) to macroscale actuators. Compared with reported macroscale data, the microscale actuator shows a 31% increase in energy conversion efficiency. Per unit actuator mass, both the force and the velocity induced by microscale actuators show an order of magnitude (22.1 and 18.5 times, respectively) increase over macroscale actuators, making them suitable for distributed flow control applications.

Dielectric barrier discharge (DBD) plasma actuators have received recent attention for various flow-control applications. To enable system-level design and optimization of plasma actuator systems-including the actuators and all power electronics-equivalent electrical circuit models of the plasma actuators are desired. To address this need, the current/voltage/power behaviors of different DBD plasma actuators designs are experimentally characterized under sinusoidal electrical excitation at varying amplitudes (4 -10 kV pk ) and frequencies (10 -20 kHz). A simplified parallel resistorcapacitor circuit is used to model the behavioral electrical impedance of the actuators. The dependencies of the circuit model parameters are studied as functions of actuator geometry, excitation amplitude, and excitation frequency. Based on this analysis, considerations for electrical impedance load matching are discussed. Nomenclature A L= load impedance vector magnitude, Ω C = matching network capacitance, F C p = plasma actuator effective load capacitance, pF d = thickness of dielectric substrate, mm f = frequency of input signal, kHz g = gap distance between electrodes, mm l = length of electrode, cm L = matching network inductance, H P avg = average power delivered to load, W R = dc resistance of matching inductor, Ω R L = load impedance resistance, Ω R S = source impedance resistance, Ω 2 R p = plasma actuator effective load resistance, MΩ V pk = peak amplitude of oscillation, kV w = width of electrode, cm X L = load impedance reactance, Ω X S = source impedance reactance, Ω Z L = complex load impedance, Ω Z S = complex source impedance, Ω L  = load impedance phase angle, degrees ω = radian frequency (2 π f), rad/s

Dielectric barrier discharge (DBD) plasma devices have been designed and manufactured with microscale dimensions utilizing semiconductor fabrication techniques. Particle image velocimetry (PIV) measurements indicate induced wall jet velocities up to 2.0 m/s. Direct force measurements using a torsional balance indicate thrust values up to 3 mN/m at 5 kV pp and 1 kHz and consume an average power of 15 W/m. The measured thrust data is applied in a numerical model to compare simulated velocity flow fields with experimental PIV data. The model shows good agreement with experimental data for the velocity and wall jet thickness for macro device geometries, but inaccurately predicts the downstream velocity decay. Microscale devices demonstrated equivalent 'thrust effectiveness' to macroscale actuators, but with a 31% improvement in mechanical-to-electrical energy conversion efficiency. The microscale DBD actuators occupy an order of magnitude reduction in device footprint and mass, and potentially enable large arrays for distributed flow control applications.

The design and construction of a torsion balance capable of micronewton resolution is presented. Comparative error analysis of two calibration methods (electrostatic force and logarithmic decrement) is presented, suggesting preference for logarithmic decrement method. Force measurement data from this balance is compared with a commercial precision balance, and found to be in good agreement. Low pressure performance of DBD plasma actuators between a pressure range of 100 to 760 Torr is assessed with the help of this thrust stand. The effect of dielectrics material (Teflon, Kapton) and thickness have been investigated. Experiments suggest that the force first increases upto a certain pressure, after which it drops sharply tending to zero. The amount of force amplification is found to be significant (several-fold) and dependent on the thickness of the dielectric. The power is found to increase with decreasing pressure, resulting in a peak effectiveness a sub-atmospheric pressure.

This paper reports the design, fabrication and testing of microelectromechanical inductors (MEMIs) that show high electrical inductance by storing energy via a mechanically compliant flexure. The microfabricated MEMI structures comprise a simple electroplated Cu beam that is placed in a static magnetic field. Upon application of ac current, the conductor vibrates via electrodynamic interactions with the magnetic field. This electromechanical behavior manifests as a highly reactive (inductive) one-port electrical impedance. In this work, we explain the microfabrication processes and the subsequent characterization of a variety of test structures, which exhibit a peak quality factor up to 5.6 with net areal inductance densities of up to 3.5 µH/mm 2. These devices are envisioned as a passive energy storage component for exploring high-power-density electrical power converters.