Advanced actuator concepts for active aeroacoustic control

Raman, Ganesh; Kibens, Valdis; Cain, Alan B.; Lepicovsky, J.

doi:10.2514/6.2000-1930

Cited by 35 publications

(24 citation statements)

References 11 publications

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“…An HTFA is created by placing a cylindrical shield between the nozzle and the tube. 21 This shield covers a large portion of the open area and creates a pulsating jet. The HTFA used in this validation created a pure acoustic tone with a frequency of 3662 Hz along with ve harmonics.…”

Section: Validation Of the Inline Microphone Arraymentioning

confidence: 99%

Exploring Noise Sources Using Simultaneous Acoustic Measurements and Real-Time Flow Visualizations in Jets

2002

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Work was carried out as part of an ongoing effort to relate instantaneous large-amplitude features of the fareld acoustic to the dynamic evolution and interaction of large-scale structures within the mixing layer of ideally expanded, high-speed, high-Reynolds-number jets. It is believed that such information is essential for a better understanding of jet noise sources and jet aeroacoustic modeling and control. The acoustic measurements were taken with a four-microphone inline array placed 30 deg to the jet axis. Conditional sampling of the data from the microphones was used to create characteristic waveforms for the large-amplitude, far-eld sound pressure peaks. The frequency content of these phase-averaged waveforms compare very well with those of the overall acoustic far eld at 30 deg. A vast majority of the large-amplitude sound events originated between four and nine jet exit diameters downstream of the nozzle. The acoustic measurements were taken simultaneously with real-time ow visualizations to determine the mechanisms that were responsible for the creation of individual far-eld acoustic peaks, and these results have identi ed three noise-generation mechanisms: intense cross-mixing-layer interaction, the tearing of large turbulent structures, and the rollup of large turbulent structures. The simultaneous data also showed that large structures entrain more ambient air into the jet and the mixing layer extends farther into the jet core during intense noise production than during periods of relative quiet.

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Section: Validation Of the Inline Microphone Arraymentioning

confidence: 99%

Exploring Noise Sources Using Simultaneous Acoustic Measurements and Real-Time Flow Visualizations in Jets

2002

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“…al. [20]. A detailed review of the evolution of the powered resonance tube actuator is given by Raman and Srinivasan [21].…”

Section: Cavity Flowsmentioning

confidence: 98%

Miniature Shock Tube Actuators for High Speed Flow Control Applications

Ramachandran¹,

Raman²

2013

International Journal of Flow Control

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There is a critical need to develop reliable high control authority flow control actuators for high speed applications. This paper introduces a novel high control authority actuator in the form of a miniature shock tube actuator. Two types of shock tubes were developed, namely, a single driver and a multiple driver shock tube. Various characterization experiments performed on these shock tubes revealed that they produced high intensity shock waves as predicted by one dimensional shock wave theory. The actuators were then tested for their effectiveness in suppressing cavity noise. The flow control experiments revealed that the shock tubes produced a 12 dB and 10 dB suppression in tonal noise for Mach numbers of 0.6 and 0.8, respectively. These results were compared to a fast acting solenoid valve providing steady and pulsating mass injection. Details of the flow field being controlled were studied using mean velocity and phase averaged measurements. With further development such actuators have potential for use in high speed flow control situations.

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“…Most of the works have been done under nonuniform §ow conditions downstream the convergent sonic nozzle exit [810]. At the same time, the resonance has been obtained for perfectly expanded supersonic jets [4,5]. Moreover, experiments with the HS generator have been carried out in a con¦ned space to study oscillations and §ow structures in the tubes placed in the channel at subsonic [12] and supersonic [13] §ow speeds.…”

Section: Introductionmentioning

confidence: 99%

“…In practice, such actuators have been already utilized for separated §ow control [14], cavity §ow control [3,4,17], and jet collision [5]. Possibilities of HG implementation for fuel and air mixing at supersonic combustion chambers have been considered as well [18,19].…”

Section: Introductionmentioning

confidence: 99%