Noise generation by a low-Mach-number jet

Laufer, John; YEN, T

doi:10.1017/s0022112083003195

Cited by 174 publications

(123 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It gave a superdirective radiation pattern, which replicated some earlier subsonic jet experiments of Laufer & Yen (1983) and has since been observed in several numerical studies of unsteady laminar shear flows, forced so as to produce vortex pairing. For example, Colonius, Lele & Moin (1997) imposed disturbances on a two-dimensional plane mixing layer at the fundamental (most unstable) frequency and two subharmonics.…”

Section: Introductionsupporting

confidence: 83%

“…The weakly nonlinear interactions studied here fall into this category since the primary instability mechanism is vortical. Quadratic nonlinearity of a similar type was also apparent in the experiments of Laufer & Yen (1983), for forced vortex pairing in a round jet. They observed that the sound intensity varied as the fourth power of the near-field mode saturation amplitude, whereas a second power would be expected for a linear relationship of the type assumed in the Huerre & Crighton (1983) model.…”

Section: Discussionmentioning

confidence: 62%

See 1 more Smart Citation

Nonlinear mechanisms of sound generation in a perturbed parallel jet flow

Sandham

Morfey

2006

J. Fluid Mech.

View full text Add to dashboard Cite

An initial value problem with relevance to jet noise is investigated. A plane parallel jet flow is subjected to a spatially localized initial disturbance and is then left to evolve according to the two-dimensional compressible Navier-Stokes equations. The hydrodynamic response is in the form of a convecting vortex packet. The Ffowcs WilliamsHawkings approach is formulated in the time domain and used to extrapolate from the simulated near field to the acoustic far field. The predominant downstream sound radiation comes from an early stage of nonlinear development of the vortex packet. Two simplified models to account for the radiation are introduced, based on nonlinear mode interactions on a prescribed base flow. The first uses two sets of linearized Euler equations, coupled via the inviscid Lilley-Goldstein acoustic analogy. This formulation separates the linear sound field from the sound field driven by nonlinear interactions; qualitative agreement of the latter with the Navier-Stokes computations demonstrates the importance of nonlinear interactions. The second model uses combinations of linear inviscid eigenmodes to drive the sound field, which allows extraction of the dominant mode interactions responsible for the observed radiation pattern. The results indicate that a difference-wavenumber nonlinear interaction mechanism dominates sound radiation from subsonic instability modes in shear flows.

show abstract

Section: Introductionsupporting

confidence: 83%

Section: Discussionmentioning

confidence: 62%

Nonlinear mechanisms of sound generation in a perturbed parallel jet flow

Sandham

Morfey

2006

J. Fluid Mech.

View full text Add to dashboard Cite

show abstract

“…17 Note also that to the best of our knowledge, no other experimental work has been published since the work of Bridges & Hussain 14 to investigate the directivity and the location of the extinction angle in excited jets. In the present work, the two radiation patterns were recovered in the same facility to avoid usual criticisms, such as a possible artefact introduced by the nozzle in the Laufer & Yen experiment.…”

Section: Motivation and Goalsmentioning

confidence: 98%

Superdirective Acoustic Radiation by Vortex Pairing in Subsonic Excited Jets

Bailly

Juvé

2006

12th AIAA/CEAS Aeroacoustics Conference (27th AIAA Aeroacoustics Conference)

View full text Add to dashboard Cite

This paper is concerned with acoustic radiation of the first subharmonic of the forcing frequency in a low-Mach-number excited jet. Two jets with laminar and transitional initial conditions are experimentally studied in the same facility. An acoustic directivity with an extinction angle in the sideline direction is observed for the laminar case (ReD = 6.7 × 10 4 ), that can be interpreted as the radiation of a compact axisymmetric quadrupolar source. A superdirective radiation is measured for the transitional jet (ReD = 1.3 × 10 5 ), that is characterized by an exponential angular variation providing a larger range of the sound pressure level. A wave extrapolation method is developed to interpret the measured near and far pressure fields of these two configurations.

show abstract

“…The documented experimental work on subsonic jets concern measurements focusing either on properties of the flow field or on properties of the acoustic far field. Turbulence characteristics of subsonic turbulent jets with a moderate to high Reynolds number (Re ≈ 10 3 −10 5 ) were reported by Panchapakesan & Lumley [24], Hussein et al [12], Zaman [40], Wygnanski & Fiedler [38], Laufer and Yen [15] and Bradshaw et al [7]. Most of the work mentioned concerned low velocity jets (Ma<0·3), and do not or briefly discuss properties of the acoustic far field.…”

Section: Introductionmentioning

confidence: 99%

Experiments on the Flow Field and Acoustic Properties of a Mach number 0·75 Turbulent Air Jet at a Low Reynolds Number

Slot

Moore

Delfos

et al. 2009

Flow Turbulence Combust

View full text Add to dashboard Cite

In this paper we present the experimental results of a detailed investigation of the flow and acoustic properties of a turbulent jet with Mach number 0·75 and Reynolds number 3·5 10 3 . We describe the methods and experimental procedures followed during the measurements, and subsequently present the flow field and acoustic field. The experiment presented here is designed to provide accurate and reliable data for validation of Direct Numerical Simulations of the same flow. Mean Mach number surveys provide detailed information on the centreline mean Mach number distribution, radial development of the mean Mach number and the evolution of the jet mixing layer thickness both downstream and in the early stages of jet development. Exit conditions are documented by measuring the mean Mach number profile immediately above the nozzle exit. The fluctuating flow field is characterised by means of a hot-wire, which produced radial profiles of axial turbulence at several stations along the jet axis and the development of flow fluctuations through the jet mixing layer. The axial growth rate of the jet instabilities are determined as function of Strouhal number, and the axial development of several spectral components is documented. The directivity of the overall sound pressure level and several spectral components were investigated. The spectral content of the acoustic far field is shown to be compatible with findings of hot-wire experiments in the mixing layer of the jet. In addition, the measured acoustic spectra agree with Tam's large-scale similarity and fine-scale similarity spectra (Tam et al., AIAA Pap 96, 1996).

show abstract

Noise generation by a low-Mach-number jet

Cited by 174 publications

References 17 publications

Nonlinear mechanisms of sound generation in a perturbed parallel jet flow

Nonlinear mechanisms of sound generation in a perturbed parallel jet flow

Superdirective Acoustic Radiation by Vortex Pairing in Subsonic Excited Jets

Experiments on the Flow Field and Acoustic Properties of a Mach number 0·75 Turbulent Air Jet at a Low Reynolds Number

Contact Info

Product

Resources

About