Computation of Shock Cell Structure of Dual-Stream Jets for Noise Prediction

Tam, Christopher K. W.; Pastouchenko, Nikolai; Viswanathan, K.

doi:10.2514/1.37045

Cited by 7 publications

(7 citation statements)

References 25 publications

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“…Shock-associated noise is transmitted into the aircraft cabin, and high levels of aft cabin noise is an issue for certain aircraft. For a Boeing project, Tam, Pastouchenko and Viswanathan 51,52 addressed this problem.…”

Section: Jet Noisementioning

confidence: 99%

See 1 more Smart Citation

Christopher Tam: Brief history and accomplishments

Viswanathan,

2024

International Journal of Aeroacoustics

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This introduction provides a brief personal background and highlights the scientific accomplishments of Professor Christopher Tam. He has maintained extremely high standards of research and an enviable track record for productivity, spanning more than five decades. The depth and breadth of his technical output are truly breathtaking, and he has inspired scores of researchers and graduate students. When the first author was an Acoustics Engineer at Lockheed, Georgia, he started collaborating with Chris in the early 1990s. There were several joint projects when the author moved to Boeing, which encompassed both fundamental research and applications. The second author has an even longer association with Chris, initially as a PhD advisee in the late 1980s and then as a co-researcher. In this special volume we pay tribute to Chris’s many achievements, an endeavor that provides us with great satisfaction and which is long overdue.

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Section: Jet Noisementioning

confidence: 99%

“…In Ref. 51 (with N. Pastouchenko and K. Viswanathan), this methodology was further extended to hot jets, leveraging the hot-jet k-ε turbulence model as delineated in Ref. 38.…”

Section: Aeroacoustics Researchmentioning

confidence: 99%

Christopher Tam: Brief history and accomplishments

Viswanathan,

2024

International Journal of Aeroacoustics

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“…The relationship between cell location and jet breakaway is also under investigation. This work is in the process of being extended so that the Rankine-Hugoniot conditions can be used to predict the shock cell structure (and thus the BBSAN) along the entire jet [26].…”

Section: Shock-associated Noise (San)mentioning

confidence: 99%

Some recent experimental results concerning turbulent coanda wall jets

Lubert

2014

The Journal of the Acoustical Society of America

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The Coanda effect is the tendency of a stream of fluid to stay attached to a convex surface, rather than follow a straight line in its original direction. As a result, in such jets mixing takes place between the jet and the ambient air as soon as the jet issues from its exit nozzle, causing air to be entrained. This air-jet mixture adheres to the nearby surface. Whilst devices employing the Coanda effect usually offer substantial flow deflection, and enhanced turbulence levels and entrainment compared with conventional jet flows, these prospective advantages are generally accompanied by significant disadvantages including a considerable increase in associated noise levels and jet breakaway. Generally, the reasons for these issues are not well understood and thus the full potential offered by the Coanda effect is yet to be realized. The development of a model for predicting the noise emitted by three-dimensional flows over Coanda surfaces would suggest ways in which this noise could be reduced or attenuated. In this paper, the results of recent modelling and experiments on a 3-D turbulent Coanda wall jet are presented. They include the relationship of SPL, shock cell distribution and breakaway to various flow parameters, and predictions of the jet boundary. The potential application of these results to important problems of practical interest such as launch noise is also discussed, and recent data pertaining to rocket launch noise sources is presented.

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“…The intake flow rate of the working airflow acoustic source at standard atmospheric pressure is (10) The airflow power is (11) The airflow efficiency is For the subsonic nozzle, it can be derived that (14)…”

Section: Schematic Diagram Of the Rotor Rotating Systemmentioning

confidence: 99%

“…Lu Xiao-jun [6] developed an infrasonic chamber generating infrasound at frequencies from 6 to 20Hz. Theoretical research on airflow acoustic sources has been carried out using Mayer's theory [7], Maa Dahyou's approximate theory [8] or numerical simulations with CFD or CAA software [9,10,11].…”

Section: Introductionmentioning

confidence: 99%

Theoretical and Experimental Study of a Prototype High-Intensity Infrasonic Acoustic Generator

Dong

Chen

Xue-Zhong

et al. 2011

Journal of Low Frequency Noise, Vibration and Active Control

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The airflow modulator, which can generate the high-intensity infrasound, is a device transferring high-pressure gas energy into acoustic energy. Based on the aerodynamic theory, an airflow modulator is designed and the equivalent throat area formulas are deduced. Approximate theory is used to investigate the maximum sound pressure level, sound power, and airflow efficiency of this airflow modulator. The working mechanisms of the infrasonic acoustic generator consisting of a modulator and a Helmholtz resonator are studied by numerical simulations. In order to carry out the experiments, a prototype device was manufactured. It is shown that from the experimental results that this device can generate a continuous infrasound pressure level of 161dB in a 6 m 3 test cavity. The simulation and the experimental results are reasonably consistent and it is estimated that such a device can generate an infrasound pressure level in excess of 162dB below 3Hz.

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Computation of Shock Cell Structure of Dual-Stream Jets for Noise Prediction

Cited by 7 publications

References 25 publications

Christopher Tam: Brief history and accomplishments

Christopher Tam: Brief history and accomplishments

Some recent experimental results concerning turbulent coanda wall jets

Theoretical and Experimental Study of a Prototype High-Intensity Infrasonic Acoustic Generator

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