Reynald Bur - Profile on Academia.edu (original) (raw)

Papers by Reynald Bur

The Shock/Boundary Layer Interaction (SBLI) over a rigid plate with an upstream 1.35 Mach number ... more The Shock/Boundary Layer Interaction (SBLI) over a rigid plate with an upstream 1.35 Mach number is characterized experimentally by unsteady pressure measurements and schlieren visualizations. Spectral Proper Orthogonal Decomposition (SPOD) is used on the schlieren videos to characterize the flow. The shock displacement spectrum is then used to chose a compliant wall. The interaction of the SBLI the compliant wall is analysed with schlieren imagery. The interaction consists on a lock-in of the flow at the structure's vibration frequency.

AIAA Journal, Jan 4, 2025

Transition measurements have been obtained through two experimental campaigns conducted independe... more Transition measurements have been obtained through two experimental campaigns conducted independently by the German AerospaceCenter and the French Aerospace Lab with the French Alternative Energies and Atomic Energy Commission on subscale models of the BOLT-1 flight experiment geometry. This paper details a crossfacility
comparison of measurements obtained at Mach 7, as well as subsequent computational analysis. Infrared thermography measurements obtained by both campaigns have facilitated a global comparison of the transition front across facilities at analogous conditions, which are found to be in good agreement. High-frequency surface pressure fluctuation data demonstrate significant amplification of instabilities with Mack-mode characteristics in the outboard regions of the acreage. These measurements are compared to stability analyses of varying fidelity. The computational methods employed to characterize the boundary-layer transition phenomena include the traditional line-marching implementation of the parabolized stability equations (PSEs), 2D eigenvalue analysis coupled with PSE. Although the 2D eigenvalue analysis is found to predict instabilities, which correlate in terms of
frequency and acreage location to the experimental measurements, the predicted amplification for these instabilities is lower than would typically be expected for transition. Line-marching results for traveling crossflow produce the best match to the experimental transition front, with a consistent transition N factor of approximately 3–3.5.

In this paper, several existing porous bleed models are implemented into the in-house RANS-solver... more In this paper, several existing porous bleed models are implemented into the in-house RANS-solver elsA, and their performance are evaluated on two different flow cases. Reference simulations are performed to evaluate the accuracy of the applied bleed models and to show the lack of modeling different plate geometries. The models significantly differ in predicting the bleed mass flux along the plate. For the turbulent supersonic boundary layer bleeding, the reference simulations demonstrate a hole diameter influence on the flow, but none of the models considers this effect. The model of Slater fits well with the reference simulation by applying it to its extracted data. However, applying the bleed models as a boundary condition results in more significant deviations from the reference simulation, leading to an overestimation of the wall shear stress and fuller boundary layer profiles downstream of the bleed region. Additionally, in the second flow case, including the shock-boundary la...

HAL (Le Centre pour la Communication Scientifique Directe), Mar 28, 2022

Porous bleed systems are widely used to mitigate the shock-induced boundary layer separation, e.g... more Porous bleed systems are widely used to mitigate the shock-induced boundary layer separation, e.g., in supersonic air intakes. However, the complex geometry makes simulations expensive and motivates the application of suitable models. In this paper, seven porous bleed models are implemented as boundary conditions in the in-house compressible RANS solver elsA. The models are compared to a three-dimensional reference simulation, including the porous bleed geometry. Different options are introduced to compare the model outcomes on different levels. None of the models is found to be suitable for the application in the shock-boundary layer interaction control. No model can accurately estimate the mass flow rate for sub-and supersonic conditions. Moreover, the approach based on a uniform suction leads to an overestimation of the porous bleed performance. Thus, the shock-induced boundary layer separation is suppressed.

AIAA AVIATION 2022 Forum

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific r... more HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

In order to be able to judge the effectiveness of transition induction in WP-2, reference flow ca... more In order to be able to judge the effectiveness of transition induction in WP-2, reference flow cases were planned in WP-1. There are two obvious reference cases—a fully laminar interaction and a fully turbulent interaction. Here it should be explained that the terms “laminar” and “turbulent” interaction refer to the boundary layer state at the beginning of interaction only. There are two basic configurations of shock wave boundary layer interaction and these are a part of the TFAST project. One is the normal shock wave, which typically appears at the transonic wing and on the turbine cascade. The characteristic incipient separation Mach number range is about M = 1.2 in the case of a laminar boundary layer and about M = 1.32 in the case of turbulent boundary layer. The second typical flow case is the oblique shock wave reflection. The most characteristic case in European research is connected to the 6th FP IP HISAC project concerning a supersonic business jet. The design speed of thi...

Experiments in Fluids, Feb 1, 2022

An important goal of the TFAST project was to study the effect of the location of transition in r... more An important goal of the TFAST project was to study the effect of the location of transition in relation to the shock wave on the separation size, shock structure and unsteadiness of the interaction area. Boundary layer tripping (by wire or roughness) and flow control devices (Vortex Generators and cold plasma) were used for boundary layer transition induction. As flow control devices were used here in the laminar boundary layer for the first time, their effectiveness in transition induction was an important outcome. It was intended to determine in what way the application of these techniques induces transition. These methods should have a significantly different effect on boundary layer receptivity, i.e. the transition location. Apart from an improved understanding of operation control methods, the main objective was to localize the transition as far downstream as possible while ensuring a turbulent character of interaction. The final objective, involving all the partners, was to b...

Experiments in Fluids, 2022

Transitional shockwave/boundary layer interactions (SBLI) are studied experimentally. Experiments... more Transitional shockwave/boundary layer interactions (SBLI) are studied experimentally. Experiments are conducted on a hollow-cylinder flare model in the R2Ch blowdown facility at a Mach number of 5 for three different Reynolds numbers in the transitional regime. Unsteady wall pressure measurements are conducted along with mean and unsteady heat flux measurements and high-speed Schlieren imaging. The images are then processed using Proper Orthogonal Decomposition (POD) and Spectral Proper Orthogonal Decomposition (SPOD) to extract relevant information. Two main phenomena are identified and documented: the oblique modes traveling in the shear layer above the recirculation region and the streaks appearing in the reattachment region. New results illustrating the multiple physical origins of the streaks, either linked with globally unstable modes and convectively unstable mechanisms, are discussed.

Theor. Comput. Fluid Dyn., 2021

A high-fidelity simulation of the massively separated shock/transitional boundary layer interacti... more A high-fidelity simulation of the massively separated shock/transitional boundary layer interaction caused by a 15-degrees axisymmetrical compression ramp is performed at a free stream Mach number of 6 and a transitional Reynolds number. The chosen configuration yields a strongly multiscale dynamics of the flow as the separated region oscillates at low-frequency, and high-frequency transitional instabilities are triggered by the injection of a generic noise at the inlet of the simulation. The simulation is post-processed using Proper Orthogonal Decomposition to extract the large scale low-frequency dynamics of the recirculation region. The bubble dynamics from the simulation is then compared to the results of a global linear stability analysis about the mean flow. A critical interpretation of the eigenspectrum of the linearized Navier-Stokes operator is presented. The recirculation region dynamics is found to be dominated by two coexisting modes, a quasi-steady one that expresses itself mainly in the reattachment region and that is caused by the interaction of two self-sustained instabilities, and an unsteady one linked with the separation shock-wave and the mixing layer. The unsteady mode is driven by a feedback loop in the recirculation region, which may also be relevant for other unsteady shock-motion already documented for shock-wave/turbulent boundary layer interaction. The impact of the large-scale dynamics on the transitional one is then assessed through the numerical filtering of those low wavenumber modes; they are found to have no impact on the transitional dynamics.

The present study is aimed to analyse the effect of passive vortex generators in a transonic inte... more The present study is aimed to analyse the effect of passive vortex generators in a transonic interaction between a shock-wave and a turbulent boundary layer in a channel flow at Mach number M = 1.45. Control of the boundary layer detachment downstream of the shock is obtained thanks to momentum transfer given by passive control devices, mechanical vortex generators (VG), located upstream of the shock and distributed in the spanwise direction. The channels lower wall is equipped with a contour profile - a bump - allowing flow separation. Two-component PIV velocity measurements are performed using the iterative gradient-based cross-correlation algorithm FOLKI-SPIV developed at ONERA. The evolution of the bulk flow and of the separated bubble due to the shock-wave boundary layer interaction is accurately quantified. Changes in the turbulent behaviour are also analysed thanks to the fluctuating fields. Comparisons with the already known flow without control give an appraisal of the eff...

Experimental Investigations on the Control of Buffet Phenomenon on a Swept Wing

40th Fluid Dynamics Conference and Exhibit, 2010

Forced Oscillation of a Shock-Wave in a Transonic Channel Flow

The purpose of the present study is to investigate two-dimensional unsteady transonic flows in a ... more The purpose of the present study is to investigate two-dimensional unsteady transonic flows in a channel with a sonic throat and a moderately strong normal shock downstream of the throat. The aim of the present work is to obtain a precise description of the unsteady flow in order to characterize the evolution of the boundary layer and the shock in space and time. Shock oscillations whose amplitudes are of about 10 times the order of the boundary layer thickness and frequencies much lower than turbulence frequencies (Strouhal number of about 3×10-4) are investigated. Two optical diagnostic methods were used. The first one is a spark light system coupled with a rotating camera. The second one is an acquisition method using a two-component laser Doppler velocimeter synchronized with a reference signal. Continuous and unsteady pressure measurements were performed.

Journal of Spacecraft and Rockets, 2001

This paper gives an extensive presentation of the accessible experimental data bank of the ONERA ... more This paper gives an extensive presentation of the accessible experimental data bank of the ONERA Fundamental/Experimental Aerodynamics Department concerning high speed flows. Sophisticated non-intrusive measurements (3-component Laser Velocimetry, Particle Image Velocimetry, Coherent Anti-Stokes Raman Scattering, Pressure Sensitive Paint), flow visualisations (Electron Beam Fluorescence, Schlieren photography, Shadowgraphy) and more classical measurements have been used to the investigation of complex aerodynamic phenomena involved in jets, nozzle and base flows, air intakes and wing profiles. These experimental data contribute to the physical analysis of high speed flow interactions and they constitute “computable” test cases with perfectly defined limit conditions on typical geometries. The presented test cases are accessible under authorisation request with the ONERA-DAFE department. The motivation of this paper is to give rise to new numerical contributions and to favour Eastern...

This paper has the objective to present an overview of recent experimental studies conducted in t... more This paper has the objective to present an overview of recent experimental studies conducted in the S3Ch transonic wind tunnel of the ONERA Meudon centre. Experimental investigations have been carried out on a civil transport aircraft power plant configuration to point out the complex wing / pylon / nacelle interference. Control of turbulent buffet phenomenon was performed on a swept wing by means of mechanical and fluidic vortex generators actuators. As a follow up study, the problem of laminar flow over wings in transonic flow conditions was tackled by an in-depth analysis of the shock dynamics in laminar conditions.

27th AIAA Aerodynamic Measurement Technology and Ground Testing Conference, 2010

This paper presents an application of the Pressure Sensitive Paint (PSP) technique to investigate... more This paper presents an application of the Pressure Sensitive Paint (PSP) technique to investigate two-dimensional unsteady flow in a transonic channel. This work takes place in the study of the transonic interaction between an oscillating shock-wave and a separated boundary layer in a channel flow. Oscillation of the shock-wave is forced thanks to a periodic variation of the downstream throat section given by a rotating elliptical shaft located near this throat inducing pressure perturbations moving upstream. The channel's lower wall is equipped with a contour profile-or a bump-allowing for flow separation. In order to achieve reduced response time, we use Anodized-Aluminum coating as PSP (AA-PSP) instead of usual paint. Thus, an aluminum insert including the bump has been manufactured in the contour profile and coated with AA-PSP. Images are acquired by using a fast frame rate camera and PSP results are compared with pressure tap and Kulite sensor measurements implemented in the insert. Spectral analysis have been carried out to assess the ability of AA-PSP for understanding unsteady aspects of the flow against unsteady pressure sensors.

Experimental and numerical study of the Mars Pathfinder vehicle

Aerospace Science and Technology, 2003

... b Aerothermodynamics Branch, NASA Langley Research Center, Hampton, VA, 23681-2199, USA. ... ... more ... b Aerothermodynamics Branch, NASA Langley Research Center, Hampton, VA, 23681-2199, USA. ... [7]. BR Hollis, Experimental and computational aerothermodynamics of a Mars Entry vehicle, Ph.D., North Carolina State University, Raleigh (USA), Dec. ...

Aerospace Science and Technology, 1998

Passive control applied to a turbulent shock wave/boundary layer interaction has been investigate... more Passive control applied to a turbulent shock wave/boundary layer interaction has been investigated by considering a two-dimensional channel flow. The field resulting from application of passive control has been probed in great detail by using a two-component laser Doppler velocimetry system to execute mean velocity and turbulence measurements. Four different perforated plates have been considered, as also the solid wall reference case. The performed measurements have shown that passive control deeply modifies the inviscid flowfield structure, the unique strong shock being replaced by a lambda shock system. This fractionning of the compression induces a substantial reduction of the wave drag associated with the interaction. On the other hand, the combined injection-suction effect taking place in the control region provokes an important thickening of the boundary layer. There results an increase of the friction drag which nearly outbalances the gain in wave drag. A determination of the total drag in the control region was made. It was found that passive control induced a modest decrease of this drag compared to the solid wall case. Also, the rugosity of the holes is an important source of drag (excrescence drag) which contributes to compromise the potential benefit of the passive control technique. 0 Elsevier, Paris

AIAA Journal, Jan 4, 2025

HAL (Le Centre pour la Communication Scientifique Directe), Mar 28, 2022

AIAA AVIATION 2022 Forum

Experiments in Fluids, Feb 1, 2022

Experiments in Fluids, 2022

Theor. Comput. Fluid Dyn., 2021

Experimental Investigations on the Control of Buffet Phenomenon on a Swept Wing

40th Fluid Dynamics Conference and Exhibit, 2010

Forced Oscillation of a Shock-Wave in a Transonic Channel Flow

Journal of Spacecraft and Rockets, 2001

27th AIAA Aerodynamic Measurement Technology and Ground Testing Conference, 2010

Experimental and numerical study of the Mars Pathfinder vehicle

Aerospace Science and Technology, 2003

Aerospace Science and Technology, 1998

8th EUCASS, 2019

Femtosecond lasers can form long plasma filaments over distances ranging from several centimetres... more Femtosecond lasers can form long plasma filaments over distances ranging from several centimetres to several meters which can be used advantageously for high speed flow control, in particular for drag reduction. Recently the first experimental demonstration of femtosecond energy deposition in a wind tunnel has been reported. This paper completes this report by presenting a parametric analysis of the effect of the femtosecond energy deposition in the flow. In particular, the effect stagnation pressure on the flow perturbation and the drag variation is investigated. Drag measurements show that higher reductions in drag are obtained for larger stagnation pressures.

54th 3AF International Conference on Applied Aerodynamics, 2019

In this work, flow control of transonic shock wave boundary layer interactions is investigated. A... more In this work, flow control of transonic shock wave boundary layer interactions is investigated. A wind-tunnel experiment featuring the Délery bump is considered and RANS simulations are carried out to compute the flow inside the test section. The massive separation due to shock wave / boundary layer interaction is controlled by fluidic Vortex Generators (VGs). A two steps Kriging optimization of the pitch and skew angles of twelve VGs is performed. The second step consisting in a precise optimization of the control of the corner flow separation. The goal of these optimizations is to minimize the total pressure losses through the shock wave and along both the boundary layer and the corner flows.

ECCOMAS Congress, 2016

Shock-wave/boundary layer interaction plays a major role in any circumstances where the flow beco... more Shock-wave/boundary layer interaction plays a major role in any circumstances where the flow becomes supersonic, either locally or in totality. This phenomenon is not clearly understood when the transitional regime (from laminar to turbulent) of the boundary layer appears during the interaction process, which is the case for compressor or turbine cascades configurations and for laminar transport/business aircraft wing.
An experimental investigation in the S8Ch research wind tunnel of the ONERA Meudon Centre at a moderate supersonic (Mach number equal to 1.6) regime is carried out to quantify the effect of the shock-wave intensity on the boundary layer transition. The detection of the transition region is obtained by means of Schlieren visualizations, IR (Infra-red) thermography and TSP (Temperature Sensitive Paint) measurements. LES computation is performed on this configuration by using the block-structured solver elsA of ONERA. Comparisons of results are performed on two configurations, one at a moderate shock intensity and the other for a strong shock intensity leading to a massive boundary layer separation.