Micro-Jet Flow Control for Noise Reduction of a Supersonic Jet from a Practical C-D Nozzle

Perrino, Michael; Munday, David; Gutmark, Ephraim; Burak, Markus Olander; Eriksson, Lars‐Erik; Prisell, Erik

doi:10.2514/6.2010-3875

Cited by 13 publications

(8 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Previous simulations [14][15][16][17] have shown to be in good agreement with experiments in terms of far-field acoustics, mean flow velocity and even turbulence kinetic energy. However in the experiments it proves to be difficult to obtain the instantaneous flow quantities within the supersonic region.…”

Section: Introductionsupporting

confidence: 63%

Exploration of temperature effects on the far-field acoustic radiation from a supersonic jet

Hafsteinsson

Eriksson

Andersson

et al. 2014

20th AIAA/CEAS Aeroacoustics Conference

Self Cite

View full text Add to dashboard Cite

Jet engines designed for high-speed aircraft commonly include C-D nozzles to obtain supersonic speeds. The radiated noise from the jet exhaust reaches acoustic levels which may cause hearing damage to the pilot and the air-field personnel even though state of the art noise protection such as noise-canceling ear muffs are employed. It is therefore extremely important to keep the noise levels as low as possible. Understanding the noise generation mechanism is of great importance in order to reduce strength of the noise sources. Typical far-field noise spectral characteristics from the supersonic jet exhaust consist of turbulent mixing noise and shock-associated noise. Another noise component named 'crackle' is radiated from the jet under certain circumstances. Although it does not appear in the noise spectra due to its characteristics, its rasping character is perceived as a dominant annoyance factor by the human ear. Since it does not appear in the spectrum other measures are needed to identify the existence of 'crackle'. Statistical tools like Skewness and Kurtosis applied to the far-and near-field pressure signals and the time derivate of the pressure signal have been shown in literature to be useful for identification of 'crackle' events. In this paper the near-field and far-field acoustic radiation from a supersonic jet is analyzed using LES with a code developed at Chalmers University of Technology. The code has previously shown to accurately capture far-field noise spectra of supersonic jets under a variety of moderately cool jet conditions. In the present study we move towards more realistic high-speed aircraft conditions with higher jet exhaust temperatures. The nozzle is operated at slightly underexpanded conditions (N PR = 4.0) and three different stagnation temperature ratios NTR = 1.0, NTR = 2.0 and NTR = 3.0. The LES results are compared with experiments conducted at the Gas Dynamics and Propulsion Laboratory at the University of Cincinnati.

show abstract

Section: Introductionsupporting

confidence: 63%

Exploration of temperature effects on the far-field acoustic radiation from a supersonic jet

Hafsteinsson

Eriksson

Andersson

et al. 2014

20th AIAA/CEAS Aeroacoustics Conference

Self Cite

View full text Add to dashboard Cite

show abstract

“…This decreased shock spacing results in the shift of the peak BBSN to higher frequency. 17,18,19 Figure 8c to 8f show the effect of injection angle on the shock structures in the jet. Increasing the injection angle creates stronger shocks in the jet which pull the shock train in further and disrupt the downstream shocks.…”

Section: Flowfield Resultsmentioning

confidence: 97%

“…17,18,19 Many considerations were taken into account to select valves that would provide high mass pulsations over a wide operating range. The difficulty of using valves for pulsed flow is the response time of the valve mechanism which limits the maximum frequency that the valve can provide pulsed flow.…”

Section: Injector Characterizationmentioning

confidence: 99%

A Comprehensive Investigation of Pulsed Fluidic Injection for Active Control of Supersonic Jet Noise

Cuppoletti

Gutmark

Hafsteinsson

et al. 2013

51st AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

Self Cite

View full text Add to dashboard Cite

Fluidic injection for noise control of high Reynolds number jets has shown promise and recent tests have demonstrated improved noise reduction while decreasing the injection mass flow required. This investigation was an experimental and numerical study on the capability of pulsed fluidic injection to reduce noise on a M d = 1.56 supersonic jet. The effect of pulse frequency, duty cycle, injector phasing, and injection angle on the noise components were studied. The pulsed injectors were characterized with hot-wire measurements. Farfield acoustics was used to survey the noise reduction of pulsed injection (up to 400 Hz) in comparison to the baseline and steady injection cases. Injection angles θinj = 30 • to 90 • with respect to the primary jet axis were investigated. High-speed shadowgraph was used to quantify the time scales involved in response of the shock train and screech instabilities with pulsed fluidic injection. LES and CAA were compared with measurements to evaluate the capability of numerical simulation of the pulsed injection configurations. It was shown that reduction of turbulent mixing noise generally scales with the actual duty cycle of applied injection. For 30 Hz injection at 20% mass flow up to up to 80% of the steady flow ∆OASPL is achieved, demonstrating that low frequency injection is capable of enhanced noise reduction at certain conditions. The shocks in the jet potential core respond in 1 ms when injection is removed, while the jet column instability requires up to 7 ms to redevelop after injection is removed. The results demonstrate the feasibility of using active control with pulsed fluidic actuators to provide at least steady flow noise reduction with significantly reduced injection mass flow.

show abstract

“…This type of nozzle is discussed extensively in other publications. 9,13,15 The instantaneous image shows the thin initial shear layer fine scale turbulence in the initial jet region. The lower two frames in Figure 5 shows the mean shock structure with 6 injectors (J = 1.35) and instantaneous image at the same condition.…”

Section: B Shadowgraph Visualizationsmentioning

confidence: 99%

“…Henderson and Norum 7 observed reduction in shock noise with no shift in the peak frequency with embedded slot injectors on a slightly underexpanded sonic nozzle. Perrino et al 9 observed strong suppression of shock noise without shifting the peak frequency with an embedded injector design on an M d = 1.56 jet. These studies only represent a subset of the work on fluidic injection for supersonic jet noise but illustrate the variation in the results for differing jets and injector designs.…”

Section: Introductionmentioning

confidence: 97%

Characterization of Supersonic Jet Noise Production and Methods for its Suppression

Gutmark¹,

Cuppoletti²,

Sánchez³

et al. 2014

50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

View full text Add to dashboard Cite

As supersonic aircraft and their turbojet engines become more powerful they emit more noise. The principal physical difference between the jets emanating from supersonic jets and those from subsonic jets is the presence of shocks in the supersonic one. This paper discusses supersonic flow features that contribute to noise emission and different methods used to reduce it. The measurements were performed using a reduced scale exhaust nozzle of a typical supersonic aircraft. The nozzle has a design Mach number of 1.56 and was tested at design and off-design conditions. Different components of supersonic jet noise were investigated including mixing noise, screech, broadband shock associated noise and crackle. Impact of chevrons on these noise components is discussed.Circumferential microjets injection resulted in reduction of far-field noise by over 2.5dB in overall sound pressure level over that obtained by chevrons, with mass flow ratio of 1% of the primary jet. Spectral results showed reduction in screech tone and broadband shock associate noise with minimal high frequency penalty typical of chevrons. Flow field measurements linked the acoustic changes to modifications induced by the fluidic injection. The optimum configuration shortened the potential core, reduced the shock cell strength, shortened the shock cell spacing, nearly doubled the spreading rate in the upstream region, and reduced the centerline peak turbulence while increasing the peak turbulence levels in the shear layer.

show abstract

Micro-Jet Flow Control for Noise Reduction of a Supersonic Jet from a Practical C-D Nozzle

Cited by 13 publications

References 6 publications

Exploration of temperature effects on the far-field acoustic radiation from a supersonic jet

Exploration of temperature effects on the far-field acoustic radiation from a supersonic jet

A Comprehensive Investigation of Pulsed Fluidic Injection for Active Control of Supersonic Jet Noise

Characterization of Supersonic Jet Noise Production and Methods for its Suppression

Contact Info

Product

Resources

About