Journal ArticleDOI
Effect of excitation on coaxial jet noise
TLDR
In this paper, an acoustic elliptic mirror was used to observe the noise sources along the jet, which revealed local noise source characteristics in different shear layer regions and noise source location changes from unexcited to excited jets.Abstract:
Coaxial model jets, including those of high bypass ratio engine exhaust hot gas conditions, were excited internally by tone and broadband noise. Acoustic excitation in the secondary (outer) duct was found to be most effective in jet noise amplification due to the sensitivity of the outer shear layer. Jet noise amplification at the subharmonic of the excitation frequency occurred in a number of cases. An acoustic elliptic mirror was used to observe the noise sources along the jet. It revealed local noise source characteristics in different shear layer regions and noise source location changes from unexcited to excited jets.read more
Citations
More filters
Journal ArticleDOI
Active control of high-speed and high-Reynolds-number jets using plasma actuators
TL;DR: In this paper, an axisymmetric Mach 1.3 ideally expanded jet of 2.54 cm exit diameter and a Reynolds number based on the nozzle exit diameter of about 1.1×106.
Journal Article
Active Control of High Speed and High Reynolds Number Jets via Plasma Actuators$^{\ast }$
Journal ArticleDOI
Active Control of a Mach 0.9 Jet for Noise Mitigation Using Plasma Actuators
TL;DR: In this article, the authors showed that when exciting the jet's preferred-mode instability at lower azimuthal modes, the jet potential core was shortened and the turbulent kinetic energy was increased significantly.
Proceedings ArticleDOI
Active Control of High Speed and High Reynolds Number Free Jets Using Plasma Actuators
TL;DR: In this article, an axisymmetric Mach 1.3 ideally expanded jet of 2.54 cm exit diameter and a Reynolds number based on the nozzle exit diameter of about 1.1 × 10.
Journal ArticleDOI
Jet Aeroacoustic Testing: Issues and Implications
TL;DR: In this paper, a major effort for improving the quality of aeroacoustic data acquired at the Boeing Low Speed Aeroacoustic Facility has been carried out, which targeted all aspects of model-scale testing and acquisition of good quality data and covered issues of flow quality, nozzle performance and acoustics.
References
More filters
Journal ArticleDOI
The role of shear-layer instability waves in jet exhaust noise
TL;DR: In this article, large-scale structures in the form of instability waves are shown to be present in an acoustically and aerodynamically well behaved jet even at high Mach numbers.
Journal ArticleDOI
The noise from the large-scale structure of a jet
TL;DR: In this paper, the authors assess the importance of eddies as a noise source of a jet and propose two simple models of the structure: the first emphasizes those features in common with waves that initially grow on an unstable shear layer but eventually saturate and decay.
Proceedings ArticleDOI
On the amplification of broadband jet noise by a pure tone excitation
D. Bechert,E. Pfizenmaier +1 more
Related Papers (5)
The evolution of instabilities in the axisymmetric jet. I - The linear growth of disturbances near the nozzle. II - The flow resulting from the interaction between two waves
J. Cohen,Israel Wygnanski +1 more