Turbulence Suppression in the Noise Producing Region of a M = 0.9 Jet

Arakeri, V.H.; Krothapalli, A.; Siddavaram, V.; Alkislar, Mehmet; Lourenco, L.

doi:10.2514/6.2002-2523

Cited by 6 publications

(4 citation statements)

References 14 publications

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“…The addition of the microjets causes a shift in the potential core length to x c ¼ 14.24r o or about one jet radius longer compared to the round jet. An extension of the potential core length was also observed experimentally by Arakeri et al 24 for a Mach 0.9 jet. They measured an extension of almost 3r o although their mass flux ratio of the microjet to the round jet was 1%.…”

Section: Resultssupporting

confidence: 76%

Unsteady numerical simulation of a round jet with impinging microjets for noise suppression

Lew

Najafi-Yazdi

Mongeau

2013

The Journal of the Acoustical Society of America

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The objective of this study was to determine the feasibility of a lattice-Boltzmann method (LBM)-Large Eddy Simulation methodology for the prediction of sound radiation from a round jet-microjet combination. The distinct advantage of LBM over traditional computational fluid dynamics methods is its ease of handling problems with complex geometries. Numerical simulations of an isothermal Mach 0.5, Re D ¼ 1 Â 10 5 circular jet (D j ¼ 0.0508 m) with and without the presence of 18 microjets (D mj ¼ 1 mm) were performed. The presence of microjets resulted in a decrease in the axial turbulence intensity and turbulent kinetic energy. The associated decrease in radiated sound pressure level was around 1 dB. The far-field sound was computed using the porous Ffowcs Williams-Hawkings surface integral acoustic method. The trend obtained is in qualitative agreement with experimental observations. The results of this study support the accuracy of LBM based numerical simulations for predictions of the effects of noise suppression devices on the radiated sound power.

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Section: Resultssupporting

confidence: 76%

Unsteady numerical simulation of a round jet with impinging microjets for noise suppression

Lew

Najafi-Yazdi

Mongeau

2013

The Journal of the Acoustical Society of America

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“…Using Zaman's 49 experimental correlation, a value of 12.5r o is obtained. From the experimental literature for unheated jets, values of approximately 10r o , 12r o and 14r o were reported by Raman et al, 56 Jordan et al 24 and Arakeri et al, 57 respectively. Hence, SP7 and SP7(Lew) compares rather well with the experimental literature.…”

Section: Test Casementioning

confidence: 79%

Recent Progress of Hot Jet Aeroacoustics using 3-D Large-Eddy Simulation

Lew

Blaisdell

Lyrintzis

2005

11th AIAA/CEAS Aeroacoustics Conference

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Improvements in computing speed over the past decade have made Large Eddy Simulation (LES) an attractive tool to study jet noise. In addition, the study of turbulent hot jets for noise prediction is desirable compared to cold/isothermal jets since all jet engines fitted on aircraft operate at hot exhaust conditions. In this regard, we present results for two heated jets with temperature ratios of Tj/T∞ = 1.76 and Tj/T∞ = 2.70, respectively. A computational grid with approximately 4.8 million grid points is used the simulation. Spatial filtering is used as an implicit subgrid scale SGS model in place of the classical Smagorinsky and Dynamic Smagorinsky models. To study the far-field noise, the porous Ffowcs Williams-Hawkings (FWH) surface integral acoustic formulation is employed. The jet development results obtained using our LES methodology are consistent with other LES data and experimental results. The predicted OASPL values for our heated jets follow the trend measured by experiments though our results over-predict by approximately 3dB. Overall, our LES methodology coupled with the Ffowcs Williams-Hawkings aeroacoustics methodology provide satisfactory results.

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“…34 Our peak values for (v x ) rms /U o and (v r ) rms /U o on the jet centerline are 0.117 and 0.100, respectively, while those of Bogey and Bailly 34 are 0.120 and 0.106, respectively. Arakeri et al 55 obtained an experimental value of 0.12 for the peak (v x ) rms /U o on the centerline of a jet with initially transient shear layers. The experimental jet studied by Arakeri et al 55 was a Mach 0.9 jet with Reynolds number 500,000.…”

mentioning

confidence: 99%

“…Arakeri et al 55 obtained an experimental value of 0.12 for the peak (v x ) rms /U o on the centerline of a jet with initially transient shear layers. The experimental jet studied by Arakeri et al 55 was a Mach 0.9 jet with Reynolds number 500,000. Lau et al 56 measured a peak value of 0.14 for (v x ) rms /U o on the centerline of a Mach 0.9, Reynolds number 1 million jet with initially turbulent shear layers.…”

mentioning

confidence: 99%

Coupling of Integral Acoustics Methods with LES for Jet Noise Prediction

Uzun

Lyrintzis

Blaisdell

2004

42nd AIAA Aerospace Sciences Meeting and Exhibit

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This study is focused on developing a Computational Aeroacoustics (CAA) methodology that couples the near field unsteady flow field data computed by a 3-D Large Eddy Simulation (LES) code with various integral acoustic formulations for the far field noise prediction of turbulent jets. Noise computations performed for a Reynolds number 400,000 jet using various integral acoustic results are presented and the results are compared against each other as well with an experimental jet at similar flow conditions. Our results show that the surface integral acoustics methods (Kirchhoff and Ffowcs Williams -Hawkings) give similar results to the volume integral method (Lighthill's acoustic analogy) at a much lower cost. To our best knowledge, Lighthill's acoustic analogy was applied to a reasonably high Reynolds number jet for the first time in this study. A database greater than 1 Terabytes (TB) in size was post-processed using 1160 processors in parallel on a modern supercomputing platform for this purpose.

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Turbulence Suppression in the Noise Producing Region of a M = 0.9 Jet

Cited by 6 publications

References 14 publications

Unsteady numerical simulation of a round jet with impinging microjets for noise suppression

Unsteady numerical simulation of a round jet with impinging microjets for noise suppression

Recent Progress of Hot Jet Aeroacoustics using 3-D Large-Eddy Simulation

Coupling of Integral Acoustics Methods with LES for Jet Noise Prediction

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