Accession Number : ADA515889


Title :   Development of Localized Arc Filament RF Plasma Actuators for High-Speed and High Reynolds Number Flow Control


Descriptive Note : Journal article preprint


Corporate Author : OHIO STATE UNIV COLUMBUS DEPT OF MECHANICAL ENGINEERING


Personal Author(s) : Kim, J H ; Nishihara, M ; Adamovich, I V ; Samimy, M ; Gorbatov, S V ; Pliavaka, F V


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a515889.pdf


Report Date : Jan 2010


Pagination or Media Count : 24


Abstract : Recently developed Localized Arc Filament Plasma Actuators (LAFPAs) have shown tremendous control authority in high-speed and high Reynolds number flow for mixing enhancement and noise mitigation. Previously, these actuators were powered by a high voltage pulsed DC plasma generator with low energy coupling efficiency of 5-10%. In the present work, a new custom-designed 8-channel pulsed radio frequency (RF) plasma generator has been developed to power up to 8 plasma actuators operated over a wide range of forcing frequencies (up to 50 kHz) and duty cycles (1-50%), and at high energy coupling efficiency (up to 80-85%). This reduces input electrical power requirements by approximately an order of magnitude, down to 12 W per actuator operating at 10% duty cycle. The new pulsed RF plasma generator is scalable to a system with a large number of channels. Performance of pulsed RF plasma actuators used for flow control was studied in a Mach 0.9 circular jet with a Reynolds number of about 623,000 and compared with that of pulsed DC actuators. Eight actuators were distributed uniformly on the perimeter of a 2.54 cm diameter circular nozzle extension. Both types of actuators coupled approximately the same amount of power to the flow, but with drastically different electrical inputs to the power supplies. Particle image velocimetry measurements showed that jet centerline Mach number decay produced by DC and RF actuators operating at the same forcing frequencies and duty cycles is very similar. At a forcing Strouhal number near 0.3, close to the jet column instability frequency, well-organized periodic structures, with similar patterns and dimensions, were generated in the jets forced by both DC and RF actuators. Farfield acoustic measurements demonstrated similar trends in the Overall Sound Pressure Level (OASPL) change produced by both types of actuators, resulting in OASPL reduction up to 1.2- 1.5 dB in both cases.


Descriptors :   *ACTUATORS , *STROUHAL NUMBER , *PLASMAS(PHYSICS) , *REYNOLDS NUMBER , *PLASMA GENERATORS , *FLOW FIELDS , OPTIMIZATION , HIGH RATE , EFFICIENCY , HIGH ENERGY , FLOW RATE , PULSES , LOW ENERGY , ACOUSTIC MEASUREMENT , LEVEL(QUANTITY) , POWER SUPPLIES , ELECTRIC POWER , MIXING , POWER , FLOW , NOISE , MACH NUMBER , RANGE(EXTREMES) , DIRECT CURRENT , RADIOFREQUENCY , SOUND PRESSURE , DECAY , INSTABILITY , CHANNELS , RADIOFREQUENCY PULSES , ELECTROHYDRODYNAMICS , MEASUREMENT , REQUIREMENTS , CONTROL , INPUT , PARTICLE IMAGE VELOCIMETRY , COUPLING(INTERACTION) , FREQUENCY


Subject Categories : Test Facilities, Equipment and Methods
      Electricity and Magnetism
      Fluid Mechanics
      Plasma Physics and Magnetohydrodynamics


Distribution Statement : APPROVED FOR PUBLIC RELEASE