Aeroacoustic power generated by multiple compact axisymmetric cavities: Effect of hydrodynamic interference on the sound production

Nakiboglu, G Günes; Hirschberg, Avraham

doi:10.1063/1.4718726

Cited by 22 publications

(7 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In most practical situations, the self-sustained oscillations, tuned by the cavity volume or depth, exhibit maximum amplitudes in the low Mach number range. The third type acoustic resonance has been recently investigated by Nakiboglu et al [27][28][29] They explored the whistling of corrugated pipes and compact axisymmetric cavities, where the acoustic feedback is provided possibly by the longitudinal standing waves inside the coaxial pipes.…”

Section: Introductionmentioning

confidence: 99%

Flow-excited acoustic resonance of a Helmholtz resonator: Discrete vortex model compared to experiments

Dai

Sun

2015

Physics of Fluids

View full text Add to dashboard Cite

The acoustic resonance in a Helmholtz resonator excited by a low Mach number grazing flow is studied theoretically. The nonlinear numerical model is established by coupling the vortical motion at the cavity opening with the cavity acoustic mode through an explicit force balancing relation between the two sides of the opening. The vortical motion is modeled in the potential flow framework, in which the oscillating motion of the thin shear layer is described by an array of convected point vortices, and the unsteady vortex shedding is determined by the Kutta condition. The cavity acoustic mode is obtained from the one-dimensional acoustic propagation model, the time-domain equivalent of which is given by means of a broadband time-domain impedance model. The acoustic resistances due to radiation and viscous loss at the opening are also taken into account. The physical processes of the self-excited oscillations, at both resonance and off-resonance states, are simulated directly in the time domain. Results show that the shear layer exhibits a weak flapping motion at the off-resonance state, whereas it rolls up into large-scale vortex cores when resonances occur. Single and dual-vortex patterns are observed corresponding to the first and second hydrodynamic modes. The simulation also reveals different trajectories of the two vortices across the opening when the first and second hydrodynamic modes co-exist. The strong modulation of the shed vorticity by the acoustic feedback at the resonance state is demonstrated. The model overestimates the pressure pulsation amplitude by a factor 2, which is expected to be due to the turbulence of the flow which is not taken into account. The model neglects vortex shedding at the downstream and side edges of the cavity. This will also result in an overestimation of the pulsation amplitude.

show abstract

Section: Introductionmentioning

confidence: 99%

Flow-excited acoustic resonance of a Helmholtz resonator: Discrete vortex model compared to experiments

Dai

Sun

2015

Physics of Fluids

View full text Add to dashboard Cite

show abstract

“…There are two possible ways of determining this function of Sr.. The first way is the numerical approach described in Refs., 11,13,15 which predicts A(Sr) with a factor of 2 accuracy. The second way, used here, is a simpler engineering approach: we estimate the shape of A(Sr) empirically.…”

Section: Model For A(sr)mentioning

confidence: 98%

“…11,13,15 The low-amplitude asymptotic behavior demonstrates that the time averaged power, P src , is proportional to ρ 0 |u ′ | 2 U cp S cp at low amplitudes |u ′ |/U cp ≪ 1.…”

Section: Introductionmentioning

confidence: 95%

“…2,3,4,5,6,7,8,9,10,11,12,13,14,15,16 The vortex shedding at the upstream edge of the corrugations is triggered by the grazing oscillating velocity, u ′ , associated with plane acoustic waves traveling along the pipe. The unsteadiness of the flow at each corrugation results into a fluctuating hydrodynamic force in the direction of the pipe axis on the pipe walls.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Corrugated pipe segment with anechoic termination: critical Mach number for whistling

Rudenko

Nakiboglu²,

Holten³

et al. 2013

19th AIAA/CEAS Aeroacoustics Conference

Self Cite

View full text Add to dashboard Cite

Corrugated pipes combine local stiffness with global flexibility, which makes them very useful. A drawback of corrugated pipes is the whistling, which results from coupling of vortex shedding with acoustic plane waves due to the flow through the pipe. We consider the possibility to reduce whistling by placing a short corrugated pipe segment along a long smooth pipe. A linear model is proposed in which the magnitude of the dipolar sound source is determined empirically. The model allows to estimate the critical Mach number of the flow through the pipe above which the whistling will always occur even for anechoic pipe terminations.

show abstract

“…Thus, they proposed a mathematical model for predicting the whistling noise; the results showed that the sound generation mainly occurred in an area around pressure nodes of standing waves, and this outcome contradicts the experimental results obtained by Kristiansen and Wiik. 6 Furthermore, Nakibog˘lu and colleagues [7][8][9][10] carried out a set of numerical and experimental investigations to understand the effect of geometry parameters on aero-acoustical interaction of the corrugated pipe. Recently, Lacombe et al 11 carried out a numerical study on the linear response of a single orifice by using computational fluid dynamics (CFD) software.…”

Section: Introductionmentioning

confidence: 99%

Numerical studies on the acoustic characteristics of the U-shaped corrugated pipes and application investigations

Xue

Sun

Jiao

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part D:

View full text Add to dashboard Cite

This paper presents a numerical study on the effect of structural parameters on acoustical transmission loss of U-shaped corrugated pipe using the control variable method. Then, the interactions between the cutoff frequencies and structural parameters are modeled based on the dimension analysis method using the numerical results. An investigation into the application of the U-shaped corrugated pipe into a simple expansion chamber muffler is carried out using both numerical and experimental methods. The results show that the U-shaped corrugated pipes have unique acoustic characteristics in noise attenuation, which resembles a resonant muffler. Furthermore, the numerical results of the transmission loss of U-shaped corrugated pipes are in good agreement with experimental results, which indicates that the transmission loss results obtained by acoustic finite element method is accurate. In addition, the corrugation height, corrugation length, and corrugation internal diameter are the factors that affect the acoustical behavior of the corrugated pipe most significantly. Moreover, the proposed empirical formulas for predicting the cutoff frequencies of U-shaped corrugated pipes are verified with high accuracy and with a prediction error within ±3.0%. What is more, the application of U-shaped corrugated pipes in expansion chamber muffler can effectively reduce the noise in the mid- to high-frequency band, which is useful to reduce the muffler volume and the amount of sound-absorbing material. Hence, automobile mufflers can be designed in a much more environmentally friendly way. In conclusion, this work could provide a theoretical basis for the acoustical design of U-shaped corrugated pipes, and it initiates a new research and application field for corrugated pipes as well.

show abstract

Aeroacoustic power generated by multiple compact axisymmetric cavities: Effect of hydrodynamic interference on the sound production

Cited by 22 publications

References 37 publications

Flow-excited acoustic resonance of a Helmholtz resonator: Discrete vortex model compared to experiments

Flow-excited acoustic resonance of a Helmholtz resonator: Discrete vortex model compared to experiments

Corrugated pipe segment with anechoic termination: critical Mach number for whistling

Numerical studies on the acoustic characteristics of the U-shaped corrugated pipes and application investigations

Contact Info

Product

Resources

About