Daniel Blacodon

Daniel Blacodon
The French Aerospace Lab ONERA | ONERA · DSNA - Department of Computational Fluid Dynamics and Aeroacoustics

About

29
Publications
3,816
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432
Citations
Citations since 2017
2 Research Items
302 Citations
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2017201820192020202120222023020406080
2017201820192020202120222023020406080

Publications

Publications (29)
Article
Active research is ongoing to improve the design of different patterns of aircrafts including innovative devices of noise reduction often assessed during experiments conducted with scaled models in wind tunnels or in situ with real aircrafts. Source localization methods play a fundamental role to identify the source locations which are at the origi...
Article
Full-text available
Phased microphone arrays have become a well-established tool for performing aeroacoustic measurements in wind tunnels (both open-jet and closed-section), flying aircraft, and engine test beds. This paper provides a review of the most well-known and state-of-the-art acoustic imaging methods and recommendations on when to use them. Several exemplary...
Article
Full-text available
Turboshaft engines can become the main source of helicopter noise at takeoff. Inlet radiation mainly comes from the compressor tones, but aft radiation is more intricate: turbine tones usually are above the audible frequency range and do not contribute to the weighted sound levels; jet is secondary and radiates low noise levels. A broadband compone...
Article
Nowadays, although aerodynamic data are still primarily sought after during wind tunnel tests, reliable acoustic measurements also become a priority for aircraft designers. In order to gather both kinds of data, aerodynamic and acoustic tests are carried out simultaneously under the same closed test section. This solution has two major drawbacks: t...
Article
Full-text available
Today, the manufacturers of aircraft want to perform at the same time aeroacoustic and classical aerodynamic tests in the wind tunnels with closed test sections in order to reduce test duration and costs involved in new aircraft developments. However, this kind of wind tunnels is not optimal for acoustics testing because the measurements are often...
Article
The development of array processing methods to extract the useful characteristics of acoustic sources such as their locations and absolute levels, starting from the measured sound field is one of the main issues in aero-acoustics. The conventional beamforming method is a very popular technique investigated to solve the power level estimation proble...
Article
Array processing represents an extremely important area in aeroacoustics: in particular, in the development of methods to extract the useful characteristics of acoustic sources, such as their locations and absolute levels, starting from the received sound field. Generally, the methods are based on a deconvolution operation to remove the undesirable...
Conference Paper
The development of array processing methods to extract the useful characteristics of acoustic sources such as their locations and absolute levels, starting from the measured sound field is one of the main issues in aero-acoustics. Generally, the methods are based on a deconvolution operation to remove the undesirable effects of smearing produced by...
Article
The TEENI project is a FP7 1st Call EU-funded project. It focuses on Helicopter Engine Exhaust Broadband Noise, and tries to identify the origin of this noise from external measurements only. Several innovative techniques are being developed to achieve this goal, but they need to be validated through comparison with internal data: several innovativ...
Article
A full-scale test on a turbofan engine has been carried out in the framework of a European project to assess the acoustic benefits of new exhausts and novel hot-stream streamliners in the reduction of the overall jet noise level radiated in the far field. The purpose of the tests is also to provide a better understanding of combustion noise, which...
Conference Paper
A full-scale test on a turbofan engine has been carried out in the framework of the European SILENCE(R) project. In the present work, it is investigated the use the so-called Spectral Estimation Method (SEM) to separate the combustion noise from others noise sources measured with a near field phased array. The comparisons between the estimated spec...
Article
Full-text available
A spectral estimation method based on measurements by a phased array was developed to estimate absolute power levels radiated by compact or extended sources. After a brief recall of its principle, numerical simulations involving several source regions are presented to illustrate the accuracy and the high-resolution performances of this new method....
Conference Paper
Full-text available
A Spectral Estimation Method (SEM) has been developed in a previous study to estimate absolute power levels radiated by point or extended sources. This new technique has the advantage to make possible an immediate comparison of various numerical results obtained during a test campaign carried out in a wind tunnel. In this article, one applies the m...
Article
Array processing is a powerful toot to extract the noise source characteristics from the acoustic signals measured during wind-tunnels tests. For many years, this measurement technology is commonly being used to study airframe noise. Conventional beam forming methods have proven their efficiency in source localization, but it is well known that the...
Article
Full-text available
A flight test campaign with a Dauphin helicopter has been conducted by ONERA, in cooperation with Istres Flight Test Center (CEV). The objective was to investigate the possibility of localizing the noise sources radiated by the helicopter from measurements performed with an array of ground fixed microphones. This study is based on a method that wor...
Conference Paper
Full-text available
Array Processing ( AP ) is a powerful tool to extract the noise source characteristics from the signals that are measured during tests performed in wind tunnel facility. This kind of means of investigation has been intensively used to study the airframe noise generated by a 1/11th scaled model Airbus A320/A321 during an experiment conducted in the...
Article
Full-text available
Prediction methods of noise radiated by vibrating structures are of great interest in many applications. Normal acceleration measurements at the radiator surface can be used in combination with a method based on the Rayleigh integral to deduce the far-field radiation corresponding to the excitation sources. This method is very attractive because it...
Article
Spinning-mode analysis methods are commonly used for studying the spatial structure of the acoustic field inside ducts. In some applications, the background noise is very high, so that the acoustic modes may be overwhelmed by spurious modes in the modal spectra. The problem may be solved by methods that greatly reduce the background noise. Four met...
Article
The spinning mode analysis of a ducted acoustic field is a powerful means for advancing the understanding of noise sources in turbofan or turboshaft engines, and it is also the main information needed to predict the far-field directivity radiated by the inlet or the nozzle. Tests were made with a circular array of fixed microphones in a nozzle cros...
Article
Full-text available
Les méthodes de prévision du bruit rayonné par les structures vibrantes ont un grand intérêt dans de nombreuses applications pratiques. Quand une mesure de l'accélération pariétale est effectuée, elle peut être utilisée avec une méthode qui s'appuie sur le calcul de l'intégrale de Rayleigh, pour estimer le niveau sonore émis en champ lointain. On d...
Article
Low-wavenumber components of the wall pressure fluctuation spectrum beneath a turbulent boundary layer are often measured by using wall-pressure microphone arrays. The microphone array acts as a wavenumber filter and its efficiency depends on the accuracy with which the relative sensitivity of the microphones is determined. A methodology is offered...
Article
Full-text available
An improved multimicrophone array technique for the localization of helicopter rotor impulsive noise sources is described and validated by experiment. Two types of data processing are presented: a linear beam forming method and a multiplicative method. For a single source, both techniques give good results, but in the case of multiple-point sources...
Article
A multimicrophone array technique for the localization of helicopter rotor impulsive noise sources is developed and applied here to the acoustic radiation of blade-vortex interaction. To isolate correctly the phenomenon, the analysis is made in the time domain rather than in the frequency one. Two kinds of array processing are presented: a linear b...
Article
Wave extrapolation methods are commonly used to evaluate the farfield radiation pattern of a complex source from nearfield measurements. The nearfield data are usually collected with transducer arrays or matrices. This standard procedure poses problems of signal conditioning, calibration, and recording that may be avoided by performing a synthetic...
Article
Far-field sound prediction may be performed from measurements of structure acceleration, associated with a method based on the Rayleigh integral. A formulation of this method is given. In practice, the acceleration distribution is sampled by an array of accelerometers. It is shown that the method works up to a frequency dependent on the spatial sam...

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