Fabien Mery
@onera.fr
DMPE/ONERA
ONERA
EDUCATION
Engineer, ISAE-ENSMA 2004-2007
PhD, ISAE SUPAERO, 2007-2010
RESEARCH INTERESTS
Aeroacoustics, acoustic liner characterization, transition onset
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Fabien Méry and Delphine Sebbane
Springer Science and Business Media LLC
AbstractWind tunnel measurements of pressure drop and steady and unsteady velocity field of a flow through fairing samples are described. 10 samples have been tested in pressure drop among which the velocity fields of 3 samples have been characterized by means of laser Doppler velocimetry. The samples are perforated plates, wiremesh plates or complex 3D geometries resulting from additive manufacturing methods. The Reynolds number of the experiments ranges from 55 000 to 117 000.
Adrien Rouviere, Lucas Pascal, Fabien Méry, Ehouarn Simon, and Serge Gratton
Cambridge University Press (CUP)
Predicting the laminar to turbulent transition is an important aspect of computational fluid dynamics because of its impact on skin friction. Traditional transition prediction methods such as local stability theory or the parabolized stability equation method do not allow for the consideration of strongly non-parallel boundary layer flows, as in the presence of surface defects (bumps, steps, gaps, etc.). A neural network approach, based on an extensive database of two-dimensional incompressible boundary layer stability studies in the presence of gap-like surface defects, is used. These studies consist of linearized Navier–Stokes calculations and provide information on the effect of surface irregularity geometry and aerodynamic conditions on the transition to turbulence. The physical and geometrical parameters characterizing the defect and the flow are then provided to a neural network whose outputs inform about the effect of a given gap on the transition through the ${\\rm \\Delta} N$ method (where N represents the amplification of the boundary layer instabilities).
Fabien Méry, Rémi Roncen, Frank Simon, Marlon Botte, and Loïc Ostorero
American Institute of Aeronautics and Astronautics (AIAA)
Maxime Lalande, Olivier Vermeersch, Fabien Méry, Philippe Reulet, and Maxime Forte
American Institute of Aeronautics and Astronautics (AIAA)
This paper deals with the computation of heat exchange in transitional boundary layers for the prediction of the laminar–turbulent transition detection using infrared thermography. An aerothermal coupling between a heat equation solver and a boundary-layer solver is presented here. This coupling is first used to provide guidelines in the academic framework of a flat plate, to achieve an enhanced temperature gradient at the transition onset in order to improve infrared imaging, and thus the transition position detection. The method is then successfully applied on a real case, by comparing the numerical predictions to measurements obtained during transonic wind-tunnel tests on a two-dimensional wing model.
Rémi Roncen, Fabien Méry, Estelle Piot, and Patricia Klotz
Elsevier BV
J. Methel, F. Méry, M. Forte, and O. Vermeersch
CIMNE
. Reducing aircraft fuel consumption by maximising the extent of laminar flow on wings assumes that the initial flow, along the wing’s attachment line, is laminar. However, if the wing is attached to a solid wall, the wing’s attachment line can be contaminated by the turbulent boundary layer developing over the solid wall for flow conditions summarised in a critical Reynolds number ( R ) greater than 250. Since typical R values encountered in flight can be well above 400, techniques, such as wall suction along the wing’s leading edge were developed to further delay the threshold R at which contamination occurs. The present paper presents the results from an experimental investigation performed on the ONERA DTP-A model fitted with leading edge suction capabilities. The experiment was performed in the ONERA F2 wind tunnel in the framework of the EU-funded Clean Sky 2 HLFC-WIN project (LPA-IADP platform), while the suction panels were manufactured by Aernnova, an aero-component manufacturing company. Hot film measurements and infra-red thermography showed that attachment line contamination could effectively be delayed up to threshold R values of 1000 for large suction flow rates. Although panels from different manufacturing processes and with different geometric characteristics were tested, no significant difference from these parameters were observed.
Victor Lafont, Fabien Méry, and Frank Simon
American Institute of Aeronautics and Astronautics (AIAA)
Fabien Mery, Remi Roncen, Frank Simon, Loïc Ostorero, and Marlon Botte
American Institute of Aeronautics and Astronautics
Adrien Rouviere, Lucas Pascal, Fabien Méry, Ehouarn Simon, and Serge Gratton
American Institute of Aeronautics and Astronautics
Adrien Rouviere, Lucas Pascal, Fabien Méry, Ehouarn Simon, and Serge Gratton
American Institute of Aeronautics and Astronautics
Adrien Rouviere, Fabien Méry, Jeanne Methel, Olivier Vermeersch, and Maxime Forte
American Institute of Aeronautics and Astronautics (AIAA)
Baptiste Baradel, Olivier Leon, Alain Giani, Philippe Combette, and Fabien Mery
IEEE
The present work provides details on the fabrication and the characterization of a micro thermal anemometer for measuring velocity fluctuations in turbulent flows. This device is based on a freestanding thin platinum wire of 60 µm × 0.2 µm × 1.5 µm acting as sensing element, placed in the middle of a 900 µm length bridge and supported by a silicon structure. A discussion is provided on the designing steps and the manufacturing process relying on micro fabrication techniques. A series of flow velocity measurements was conducted in a turbulent boundary layer to evaluate the response of this sensor. The results are discussed and compared with conventional hot wire anemometry measurements and semi-empirical models to highlight the relevance of this new sensor for turbulence studies.
Victor Lafont, Fabien Méry, Philippe Reulet, and Frank Simon
Springer Science and Business Media LLC
Victor Lafont, Fabien Mery, and Frank Simon
American Institute of Aeronautics and Astronautics
Remi Roncen, Pierre Vuillemin, Patricia Klotz, Frank Simon, Fabien Méry, Delphine Sebbane, and Estelle Piot
Institute of Noise Control Engineering (INCE)
In the context of noise reduction in diverse applications where a shear grazing flow is present (i.e., engine nacelle, jet pump, landing gear), improved acoustic liner solutions are being sought. This is particularly true in the low-frequency regime, where space constraints currently limit the efficiency of classic liner technology. To perform the required multi-objective optimization of complex meta-surface liner candidates, a software platform called OPAL was developed. Its first goal is to allow the user to assemble a large panel of parallel/serial assembly of unit acoustic elements, including the recent concept of LEONAR materials. Then, the physical properties of this liner can be optimized, relatively to given weighted objectives (noise reduction, total size of the sample, weight), for a given configuration. Alternatively, properties such as the different impedances of liner unit surfaces can be optimized. To accelerate the process, different nested levels of optimization are considered, from 0D analytical coarse designs in order to reduce the parameter space, up to 2D plan or axisymmetric high-order Discontinuous Galerkin resolution of the Linearized Euler Equations. The presentation will focus on the different aspects of liner design considered in OPAL, and present an application on different samples made for a small scale aeroacoustic bench.
Frank Simon, R. Roncen, P. Vuillemin, P. Klotz, Fabien Méry, and E. Piot
Institute of Noise Control Engineering (INCE)
In the context of aircraft noise reduction in varied applications where a cold or hot shear grazing flow is present (i.e., engine nacelle, combustion chamber, jet pump, landing gear), improved acoustic liner solutions are being sought. This is particularly true in the low-frequency regime, where space constraints limit the efficiency of conventional liner technology. Therefore, liner design must take into account the dimensional and phenomenological characteristics of constituent materials, assembly specifications and industrial requirements involving multiphysical phenomena. To perform the single/multi-objective optimization of complex meta-surface liner candidates, a software platform coined OPAL (OPtimisation of Acoustic Liners) was developed. Its first goal is to allow the user to assemble a large panel of parallel/serial elementary acoustic layers along a given duct. Then, the physical properties of this liner can be optimized, relatively to weighted objectives, for a given flow and frequency range: impedance target, maximum absorption coefficient or transmission loss with a total sample size and weight... The presentation will focus on the different elementary bricks and assembly of a problem (from 0D analytical coarse designs in order to reduce the parameter space, up to 2D plan or axisymmetric high-order Discontinuous Galerkin simulations of the Linearized Euler Equations).
R. Roncen, E. Piot, F. Méry, F. Simon, M. G. Jones, and D. M. Nark
American Institute of Aeronautics and Astronautics (AIAA)
While intrinsic by definition, the impedance measured by impedance eduction has been shown to depend on the direction of the incident waves relative to the mean flow. The purpose of the present wor...
V. Lafont, F. Méry, R. Roncen, F. Simon, and E. Piot
American Institute of Aeronautics and Astronautics (AIAA)
This paper investigates the combined effects of high sound pressure level and grazing flow on impedance eduction for acoustical liners. Experiments are conducted in the grazing flow duct at ONERA (...
Rémi Roncen, Fabien Méry, and Estelle Piot
Acoustical Society of America (ASA)
An in-duct modal decomposition technique is described. The basis for the technique is to consider the decomposition as an inference problem. Using transfer function measurements at the duct walls, a Bayesian inference is conducted to evaluate the acoustic modal coefficients in the presence of uncertainties. These uncertainties encompass model errors, microphone measurements error, and uncertainty on the flow profile. The formalism of the direct problem of modal decomposition in a ducted shear flow is first developed. The case of a circular cross-section duct is then treated without and with a flow, using synthetic noisy signals for the inference problem.
Olivier Léon, Fabien Méry, Estelle Piot, and Claudia Conte
Springer Science and Business Media LLC
Fabien Mery, Delphine Sebbane, Remi Roncen, Estelle Piot, and Frank Simon
American Institute of Aeronautics and Astronautics
On modern aircrafts, passengers and crew breathe a mixture of fresh and recirculated air. This combination allows the regulation of temperature, pressure and humidity. The air is bled from the engines and supplied to air conditioning units. It is then ducted into the cabin, circulated and eventually drawn into the lower fuselage where it is sucked out by the pressurization outow valve for the cycle to begin again. Besides creating a safe and comfortable environment, the aircraft air conditioning systems generate noise. The noise radiated from the aircrafts' air conditioning systems is reduced thanks to acoustic liners. These liners present a major design challenge because of the need to address a wide range of conicting requirements. Acoustic liners must provide high levels of noise reduction over a wide range of operating conditions. They should also be light and exible to meet strict weight and tight space restrictions. Until now, acoustic liners for air conditioning systems are made of porous materials, very efficient for sound absorption in the high-frequency range. Locally-reacting liners made of a multiple layers of a honeycomb core topped by a perforated facesheet are classically used in turbofan engine nacelles for mitigating fan noise. These liners are denoted as SDOF (Single Degree of Freedom) or DDOF (Double Degree of Freedom) liners depending on the number of perforate-over-honeycomb layers. Mid-frequency noise attenuation (in the range of 1-5 kHz) can easily be obtained by tuning the liner acoustic impedance to a target value specific to the duct environment (geometry, ow Mach number, noise source modal content). The impedance achieved by a SDOF or DDOF liner depends on its geometry (porosity and holes diameter of the facesheets, honeycomb depth), on the grazing ow features, and on the noise source level. During the ALIAS project,5 a simulation-based design process was implemented to assess the liners concepts that were the best suited for attenuating the air pump noise in the mid-frequency range. A trade-off between acoustic efficiency, weight and cost manufacturing issues was made before selecting the liners. In the framework of the IDEAS Project funded within the European initiative CleanSky 2 SYSTEM- ITD, ONERA, the French Aerospace Lab, and the SMEs ATECA and Poly-Shape combine their research and technological capabilities to propose new ideas in the domain of acoustic liners and in-duct modal detection for air conditioning systems from Liebherr Aerospace. A compact innovative acoustic liner is designed in order to mitigate this jet pump noise source over all the frequency range, while meeting the strict weight, costs and tight space restrictions. This paper presents two concepts of liner for a large frequency range with high industrial constraints. These liner architectures need to be assessed regarding the ow effect and the incident sound pressure level. The acoustic behavior and the effect of a grazing ow on the impedance of each liner concept are assessed in this paper. This liner concept analysis enables to increase our experimental data base and to identify reliable liner models to optimize the best liner solution regarding industrial cases.
Remi Roncen, Estelle Piot, Fabien Mery, Frank Simon, Michael G. Jones, and Douglas M. Nark
American Institute of Aeronautics and Astronautics
The acoustic impedance of liners is a key parameter for their design, and depends on theflow conditions, i.e., the sound pressure level and the presence of a grazing flow. The surfaceimpedance of a locally reacting liner is defined as a local intrinsic property relating the acousticpressure to the normal acoustic particle velocity at the liner surface. Impedance eductiontechniques are now widely used to retrieve the impedance of liners in aeroacoustic facilities inthe presence of a shear grazing flow. While surface impedance is intrinsic by definition, theeduced impedance has recently been shown to depend on the direction of the incident wavesrelative to the mean flow. Different studies have investigated this issue by considering differentacoustic propagation models used in the eduction process in the hope of matching the educedvalues. The purpose of the present work is to continue the previous investigations by evaluatingthe influence of the shear flow profile on the educed impedance, while considering a Bayesianinference process in order to evaluate the uncertainty on the educed values. The identifieduncertainties were not able to totally account for the observed discrepancies between educed impedances.
Fabien Mery, Victor Lafont, Remi Roncen, Frank Simon, and Estelle Piot
American Institute of Aeronautics and Astronautics