Résonances acoustiques dans un tube corrugué sous écoulement

Abstract : The problem of acoustic resonances in a corrugated pipe under flow has been studied both experimentally and numerically. Analyzes concerning the flow structure during the whistling phenomenon are performed. They aim to better understand the nature of the phenomenon and the aeroacoustic coupling involved.Laboratory experiments were carried out on three geometries of corrugated veins of short lengths(1 to 2 m). An air flow was applied for speeds between 10 and 25 m/s and a pressure close toatmospheric pressure showing the longitudinal acoustic resonances. Measurements by hotwires,microphone and laser technique (Particle Image Velocimetry) allowed to characterize the flow under conditions favoring whistling. On these different measures, we applied a spatio-temporal reconstructiontechnique, the Linear Staochastic Estimation (LSE). Numerical simulations of Lattice Boltzmann method (2D, POWERFLOW code, EXA) have made possible the prediction of this aeroacousticphenomenon with a good determination of the preferential modes according to the flow conditions in ashort corrugated pipe (1 to 2 m).Finally, high pressure tests (P < 40 bars) conducted on an industrial riser of 18 m completed thisstudy. In this case, the resonance produced became transverse. Signal processing such as the HilbertHuang transformation or Gabor wavelet has been applied, highlighting the influence of the corrugation geometry on whistling in time, frequency and amplitude.In both configurations, whether in the laboratory or in an industrial facility, the structures within the flow, whose characteristic frequency was whistling, moved at the rate of flow. In both cases, when the corrugated pipe sings, velocity and pressure measurements in the flow show a predominance of the pseudo-noise on the sound signal. The excitation observed on the risers in the whistling condition is that of a pseudo-noise of very high level of fluctuations without non-linear distortion, and this despite a level of 170 dB.
Complete list of metadatas

https://tel.archives-ouvertes.fr/tel-01864248
Contributor : Abes Star <>
Submitted on : Wednesday, August 29, 2018 - 3:32:07 PM
Last modification on : Monday, March 4, 2019 - 2:04:11 PM
Long-term archiving on : Friday, November 30, 2018 - 5:09:54 PM

File

Manuscrit_GGaleron.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-01864248, version 1

Citation

Gaëtan Galeron. Résonances acoustiques dans un tube corrugué sous écoulement. Mécanique des fluides [physics.class-ph]. Ecole Centrale Marseille, 2018. Français. ⟨NNT : 2018ECDM0004⟩. ⟨tel-01864248⟩

Share

Metrics

Record views

236

Files downloads

657