title: Experimental localization of an acoustic sound source in a wind-tunnel flow by using a numerical time-reversal technique.
abstract: The possibility of using the time-reversal technique to localize acoustic sources in a wind-tunnel flow is investigated. While the technique is widespread, it has scarcely been used in aeroacoustics up to now. The proposed method consists of two steps: in a first experimental step, the acoustic pressure fluctuations are recorded over a linear array of microphones; in a second numerical step, the experimental data are time-reversed and used as input data for a numerical code solving the linearized Euler equations. The simulation achieves the back-propagation of the waves from the array to the source and takes into account the effect of the mean flow on sound propagation. The ability of the method to localize a sound source in a typical wind-tunnel flow is first demonstrated using simulated data. A generic experiment is then set up in an anechoic wind tunnel to validate the proposed method with a flow at Mach number 0.11. Monopolar sources are first considered that are either monochromatic or have a narrow or wide-band frequency content. The source position estimation is well-achieved with an error inferior to the wavelength. An application to a dipolar sound source shows that this type of source is also very satisfactorily characterized.
authors.affiliation: Institut PPRIME UPR 3346, CNRS, Université de Poitiers, ENSMA, Bât. B17-6 Rue Marcel Doré, 86022 Poitiers Cedex, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Padois
authors.forename: Christian
authors.initials: C
authors.lastname: Prax
authors.forename: Vincent
authors.initials: V
authors.lastname: Valeau
authors.forename: David
authors.initials: D
authors.lastname: Marx
mesh_terms: D000162:Acoustics / Q000295:instrumentation; D003198:Computer Simulation; D004867:Equipment Design; D005583:Fourier Analysis; D008962:Models, Theoretical; D009038:Motion; D009622:Noise; D009716:Numerical Analysis, Computer-Assisted; D011312:Pressure; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted; D013997:Time Factors; D014160:Transducers, Pressure; D014919:Wind