Modeling Pulsed-Blowing Systems for Flow Control

Kim, Byung-Hun; Williams, David R.; Emo, Steve; Acharya, Mukund

doi:10.2514/1.10285

Cited by 18 publications

(10 citation statements)

References 17 publications

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“…3d. These trends have been noticed in similar actuation systems in [47], where a lumped-element model was proposed to explain the observations.…”

Section: Spinning-valve Characterizationsupporting

confidence: 66%

Active Control of Noise from Hot Supersonic Jets

Sinha¹,

Towne²,

Colonius³

et al. 2018

AIAA Journal

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This paper presents diagnostic experiments aimed at understanding and mitigating supersonic jet noise from the coherent wave-packet structures that are the source of peak aft-angle mixing noise. Both isothermal and heated, nearly perfectly expanded, Mach 1.5 jets were forced in the near-nozzle region with air injection generated by a spinning-valve device designed to excite the jet at frequencies approaching those of the dominant turbulent structures. Substantial reductions in the peak aft-angle radiation were achieved with steady blowing at amplitudes corresponding to 2-6% of the mass flow rate of the primary jet. The noise benefit saturated at mass flow rates above 4%, with as much as a 6 dB reduction in overall sound pressure level at aft angles. Increasing the mass flow rates yielded a monotonically increasing high-frequency noise penalty at the sideline, where noise levels in the natural jet were already 15 dB lower than the aft-angle peak, so that the penalty due to actuation was minor. Although both steady and periodic unsteady mass injections were produced by the spinning valve when it rotated, it was calibrated to hold the steady mass flow rate constant as the frequency of unsteady blowing was changed. In this way, the effect of steady and unsteady blowings on the acoustic field could be decoupled. It is shown that the noise benefit was uniquely associated with the steady component of blowing, whereas the unsteady component resulted in additive tones in the spectra. This implied linearity is consistent with theory and experiments showing that the wave-packet structures, which give rise to the dominant aft-angle radiation, evolve in the turbulent mean flowfield in a nearly linear fashion from their origin in the near-nozzle region. The interpretation of noise reduction is that the steady component of blowing spreads the mean flow more rapidly, resulting in weaker wave packets. Periodic unsteady blowing forces coherent wave packets that are largely uncorrelated from the random natural ones, which then leads to the observed additive tones.

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“…3d. These trends have been noticed in similar actuation systems in [47], where a lumped-element model was proposed to explain the observations.…”

Section: Spinning-valve Characterizationsupporting

confidence: 66%

Active Control of Noise from Hot Supersonic Jets

Sinha¹,

Towne²,

Colonius³

et al. 2018

AIAA Journal

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“…Fig.1 shows a typical equipment layout of full-mechanized mining face. In the face and ventilation lane, transportation roadway in different locations have different acoustic power levels of noise sources, which work according to a certain timing of radiation noise, and it formed a mining job face of environmental noise with the following characteristics (Zhao, 1984;Zhang, 1988;Ye, 1996;Zhou et al, 2002;Kim et al, 2005;Song and Gao, 2006;Bai et al, 2007;Huang et al, 2007;Wu , 2007;Ericson and Palmberg, 2007;Zhang, 2007;Gu et al, 2007;Peng et al, 2009). …”

Section: The Characteristics Of the Machine Noise On Working Facementioning

confidence: 98%

“…Lighehill audible turbulence theory and vortex sound theory are used to study the fluid mechanical turbulence noise radiation mechanism and control approach (Gao et al, 2002;Ericon and Palmberg, 2007). Pulsating flow noise mechanism and many effective control measures have been analyzed and put forward based on the mathematical model of pulsating fluid systems (Kim et al, 2005). These studies have a great value and significance for the mining machinery and other various types of machinery noise analysis and control.…”

Section: Research Statusmentioning

confidence: 99%

The main projects and development status of noise forecasting and controlling on working face in coal mine

Peng

Guo

Litao

et al. 2010

J Coal Sci Eng China

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Noise from the machine on coal working face seriously influenced the miners' physical and mental health, and also, due to the noise, there may be a major hidden danger in safety from accidents as all safety warning signals may be masked by the noise. This paper summarized the features of mine environmental noise on working face, such as the variety of noise sources, the continuity of high intensity and slow attenuation in narrow space, etc. The main projects about noise forecasting and controlling on working face was emphatically expounded; the development status about mines machinery noise mechanism and environmental noise acoustic characteristics of space-time of these main research topics were also introduced.

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“…Kim et al (2005) extended the lumped element technique to consider the relevant case of the infl uence of delays associated with long lengths of tubing, as in Fig. Kim et al (2005) extended the lumped element technique to consider the relevant case of the infl uence of delays associated with long lengths of tubing, as in Fig.…”

Section: Fluidic Actuatorsmentioning

confidence: 99%