Aeroacoustics of the Edge Tone: 2D-3D Coupling Between CFD and CAA

“…Considering that in the 2-D CFD simulations of (Vaik et al. 2013) the first mode shift occurred at , the prediction of the mode shift by the model is reasonable. The calculated frequency of the second stage (mode 2) agrees exceptionally well with the measurement.…”

Section: Modelling the Feedback Mechanismmentioning

confidence: 65%

A feedback model of the edge tone, using the adjoint Orr–Sommerfeld equation

2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…The streamlines that exit from the nozzle (shown e.g. in Figure 14 of [27]) were parallel between the nozzle and the wedge, and only separated after a short distance from the tip of the wedge. The z = 0 mm plane, as well as the streamlines are coloured by the velocity magnitude.…”

Section: Verification Of the Planar Nature Of The Flowmentioning

confidence: 99%

Frequency and Phase Characteristics of the Edge Tone, Part I

Vaik

Varga²,

Paál³

2014

Period. Polytech. Mech. Eng.

Self Cite

View full text Add to dashboard Cite

This paper is the first half of a two-part publication. In these papers the well-known low Mach number edge tone configuration is investigated which is one of the canonical selfsustained flow configurations leading to simple aeroacoustic flow phenomena. The configuration consist of a planar free jet that impinges on a wedge shaped object. Under certain circumstances the jet starts to oscillate more or less periodically thereby creating an oscillating force on the wedge that acts as a dipole sound source. This first part contains a detailed literature overview and the qualitative discussion of the authors' results of a detailed parametric study. The formulae in the literature describing the dependence of the frequency on exit velocity and nozzle-wedge distance show a broad scatter, although similar in form. In this paper a systematic and thorough study is made by experimental and numerical means and remarkable agreement is found.

show abstract

“…In recent years, the edge tone has been numerically studied using several different methods. 17–24 Dougherty et al. adopted a compressible fluid simulation and partially reproduced the structure of the mode-transition region.…”

Section: Introductionmentioning

confidence: 99%

“…17 Paál and Vaik reproduced mode transitions in a laminar flow regime with an incompressible fluid simulation, but they relied on a hybrid method to reproduce acoustic waves. 21,22 A previous work 24 compared the result of compressible Large Eddy Simulation (LES) with that of compressible DNS for a 2 D edge tone model. The first and second modes reproduced by the compressible DNS with extremely small numerical grids, 26 well follow Brown’s equation.…”

Section: Introductionmentioning

confidence: 99%

Numerical study on edge tone with compressible direct numerical simulation: Sound intensity and jet motion

Iwagami

Tabata

Kobayashi

et al. 2021

International Journal of Aeroacoustics

View full text Add to dashboard Cite

A two-dimensional model of the edge tone is studied by a highly accurate and reliable method of direct numerical simulation of the compressible Navier-Stokes equations, and used to verify key features observed in previous experimental and numerical studies, and to discover new features related to the jet motion and the edge tone generation mechanism. The first and second modes of the edge tone that are numerically reproduced agree well with Brown’s equation. In the mode transition region, dynamical mode transition is observed at a fixed jet velocity. For both first and second modes, the pressure distributions are antisymmetric with respect to the edge plate, and the sound intensity is proportional to the fifth power of the jet velocity. These results are consistent with the edge tone being radiated from a dipole-like source. Spatial profiles of the velocity and the velocity variance of the oscillating jet are also investigated for each mode over a range of the jet velocity including the mode transition regime. The amplitude of the velocity oscillation becomes constant with increasing jet velocity, while a measure of the amplitude of the velocity variance profile, which is introduced to characterize the strength of the jet fluctuation and named the ’fluctuation strength’, is proportional to the third power of the jet velocity. Some properties of the fluctuation strength correspond to properties of the sound intensity, including the first mode having larger amplitude than the second mode, and the way of deviating from the power law at smaller values of jet velocity and in the mode transition region. It is proposed that the third-power law exhibited by behavior of the fluctuation strength could be related to the increase of the skewness observed in the velocity profile with increase of jet velocity, and a model calculation is used to support this proposal.

show abstract

Aeroacoustics of the Edge Tone: 2D-3D Coupling Between CFD and CAA

Cited by 6 publications

References 0 publications

A feedback model of the edge tone, using the adjoint Orr–Sommerfeld equation

A feedback model of the edge tone, using the adjoint Orr–Sommerfeld equation

Frequency and Phase Characteristics of the Edge Tone, Part I

Numerical study on edge tone with compressible direct numerical simulation: Sound intensity and jet motion

Contact Info

Product

Resources

About