References of "Terrapon, Vincent"
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See detailAn efficient flamelet-based combustion model for compressible flows
Saghafian, Amirreza; Terrapon, Vincent ULiege; Pitsch, Heinz

in Combustion and Flame (2015), 162(3), 652-667

A combustion model based on a flamelet/progress variable approach for high-speed flows is introduced. In the proposed formulation, the temperature is computed from the transported total energy and ... [more ▼]

A combustion model based on a flamelet/progress variable approach for high-speed flows is introduced. In the proposed formulation, the temperature is computed from the transported total energy and tabulated species mass fractions. Only three additional scalar equations need to be solved for the combustion model. Additionally, a flamelet library is used that is computed in a pre-processing step. This approach is very efficient and allows for the use of complex chemical mechanisms. An approximation is also introduced to eliminate costly iterative steps during the temperature calculation. To better account for compressibility effects, the chemical source term of the progress variable is rescaled with the density and temperature. The compressibility corrections are analyzed in an a priori study. The model is also tested in both Reynolds-averaged Navier–Stokes (RANS) and large-eddy simulation (LES) computations of a hydrogen jet in a supersonic transverse flow. Comparison with experimental measurements shows good agreement, particularly for the LES case. It is found that the disagreement between RANS results and experimental data is mostly due to the mixing model deficiencies and the presumed probability density functions used in the RANS formulation. A sensitivity study of the proposed model shows the importance of the compressibility corrections especially for the source term of the progress variable. [less ▲]

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See detailOn some drawbacks and possible improvements of a Lagrangian finite element approach for simulating incompressible flows
Cerquaglia, Marco Lucio ULiege; Deliège, Geoffrey ULiege; Boman, Romain ULiege et al

in Oñate, E.; Bischoff, M.; Owen, D.R.J. (Eds.) et al Proceedings of the IV International Conference on Particle-Based Methods – Fundamentals and Applications (2015)

Detailed reference viewed: 48 (17 ULiège)
See detailImplementation of the blade element theory to investigate the aerodynamic performance of a ducted fan UAV
Guissart, Amandine ULiege; Arendt, Dimitri; Terrapon, Vincent ULiege et al

Scientific conference (2015)

Detailed reference viewed: 73 (27 ULiège)
See detailDirect numerical simulations of mixed convection in a turbulent channel flow
Sid, Samir ULiege; Terrapon, Vincent ULiege; Dubief, Yves

Conference (2014, November 23)

Wall-bounded turbulence has been extensively studied by the scientific community during the last decades. Much effort has been devoted to identify the role that coherent structures and energy exchanges ... [more ▼]

Wall-bounded turbulence has been extensively studied by the scientific community during the last decades. Much effort has been devoted to identify the role that coherent structures and energy exchanges play in turbulent channel flows. However, in many engineering applications, wall-bounded flows are subjected to additional physical phenomena. For instance, applying a temperature differential to the channel walls leads to a modified turbulent state which results from a balance between buoyancy, inertia and viscosity effects. Although, forced and natural convection have been widely studied separately, the coupling between both and its consequences on turbulence features are still not fully understood. In the present work, direct numerical simulations of a buoyant turbulent channel flow are reported for different values of the Reynolds and Richardson numbers. The energy exchanges between potential and kinetic energy and their impact on coherent structures are investigated. Macroscopic quantities (e.g.: Nusselt number) and statistics are compared with those obtained in forced convection flows. Finally, the influence of the ratio between inertia and buoyancy effects (i.e. Richardson number) is discussed. [less ▲]

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See detailSimulation of elastic and elasto-inertial turbulence in straight channel flows
Dubief, Yves; Terrapon, Vincent ULiege; Sid, Samir ULiege

Conference (2014, November 23)

Elastic turbulence (ET, Nature 410, 905, 2000) is a chaotic flow state generated and sustained by polymer additives at vanishing Reynolds numbers. It is generally accepted that elastic turbulence occurs ... [more ▼]

Elastic turbulence (ET, Nature 410, 905, 2000) is a chaotic flow state generated and sustained by polymer additives at vanishing Reynolds numbers. It is generally accepted that elastic turbulence occurs when the mean flow streamlines are curved. Elasto-inertial turbulence (EIT, PNAS 220, 10557, 2013) is a similar state of turbulence that happens in inertial flows with mean straight flow streamlines at Reynolds numbers for which the flow is laminar in the absence of polymers. A recent experiment (PRL 110, 174502, 2013) has shown that ET generated by the insertion of cylinders at the inlet of a low Reynolds number channel flow is sustained downstream of the perturbation. This experiment suggests a possible relation between ET and EIT. Our study will first confirm that sustained ET can be triggered in low-Reynolds number channel flows. ET is shown to exist in two- and three-dimensional simulations for Reynolds numbers of the order of 100 or less. Much like the aforementioned experiment, the initial conditions triggering ET cause the flow streamlines to be curved for a short duration at the beginning of the simulation. Our study will then discuss the similarities and differences between ET and EIT. [less ▲]

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See detailNumerical Investigation Of Fiber Glass Process
Chouffart, Quentin ULiege; Simon, Philippe; Terrapon, Vincent ULiege

Conference (2014, September)

The manufacturing process of glass fibers used for the reinforcement of composite material consists in drawing a glass melt at high temperature through the bushing plate into fibers using a winder. This ... [more ▼]

The manufacturing process of glass fibers used for the reinforcement of composite material consists in drawing a glass melt at high temperature through the bushing plate into fibers using a winder. This process is sensitive to numerous disturbances that can cause the fiber to break during the drawing process. In order to understand the origin of these failures and improve the process efficiency, it is important to understand the physics of the forming fiber. We investigate here the underlying physics of the forming of a single fiber through numerical simulations. In particular, we focus on the region from the hole tips at the bushing plate to the glass transition point. The influence of key parameters (e.g. operating windows, and heat transfers mechanisms) on the fiber radius attenuation and the internal stresses is investigated through a sensitivity analysis. In addition, the impact of the temperature variations at the bushing plate is investigated. Finally, we show how the forming stress is influenced by these parameters. It is found that the internal stress can be minimizing by varying the operating windows. On the other hand, results also demonstrate that the heat pattern of the bushing plate is one of the most important causes for disturbance in the process. [less ▲]

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See detailOn the role of pressure in elasto-inertial turbulence
Terrapon, Vincent ULiege; Dubief, Yves; Soria, Julio

in Journal of Turbulence (2014), 16(1), 26-43

The dynamics of elasto-inertial turbulence is investigated numerically from the perspective of the coupling between polymer dynamics and flow structures. In particular, direct numerical simulations of ... [more ▼]

The dynamics of elasto-inertial turbulence is investigated numerically from the perspective of the coupling between polymer dynamics and flow structures. In particular, direct numerical simulations of channel flow with Reynolds numbers ranging from 1000 to 6000 are used to study the formation and dynamics of elastic instabilities and their effects on the flow. Based on the splitting of the pressure into inertial and polymeric contributions, it is shown that the polymeric pressure is a non-negligible component of the total pressure fluctuations, although the rapid inertial part dominates. Unlike Newtonian flows, the slow inertial part is almost negligible in elasto-inertial turbulence. Statistics on the different terms of the Reynolds stress transport equation also illustrate the energy transfers between polymers and turbulence and the redistributive role of pressure. Finally, the trains of cylindrical structures around sheets of high polymer extension that are characteristics of elasto-inertial turbulence are shown to be correlated with the polymeric pressure fluctuations. [less ▲]

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See detailNumerical Investigation of Cooling in the Continuous Fiber Glass Drawing Process
Chouffart, Quentin ULiege; Simon, Philippe; Terrapon, Vincent ULiege

in Proceedings of the 15th International Heat Transfer Conference (2014, August)

The manufacturing process of glass fibers used for the reinforcement of composite material consists in drawing a glass melt at high temperature through an array of thousands of small orifices (i.e., the ... [more ▼]

The manufacturing process of glass fibers used for the reinforcement of composite material consists in drawing a glass melt at high temperature through an array of thousands of small orifices (i.e., the bushing plate) into fibers using a winder. This process is sensitive to numerous disturbances that can cause a fiber to break during the drawing process. This paper analyzes how the stress in the fiber depends on the controlling parameters of the process. The approach relies on numerical simulations and sensitivity analysis. Both a semi-analytical one-dimensional model and a more complex two-dimensional axisymmetric model are used. It is first found that radial variations across the fiber are small compared to changes in the axial direction and that the one-dimensional approximation is accurate enough to describe the major trends in the process. Sensitivity analyses on some physical parameters controlling the heat transfers and on process parameters are then performed to identify strategies to reduce the axial stress. In particular, it is shown that, for a given fiber diameter, the stress is minimized if the glass melt temperature and the drawing velocity are increased. This approach is then applied to quantify the effect of inhomogeneous heat patterns on a bushing plate with a large number of fibers. [less ▲]

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See detailNumerical Investigation of Continuous Fiber Glass Drawing Process
Chouffart, Quentin ULiege; Simon, Philippe; Terrapon, Vincent ULiege

Conference (2014, May 30)

The manufacturing process of glass fibers used for the reinforcement of composite material consists in drawing a glass melt at high temperature through the bushing plate into fibers using a winder. This ... [more ▼]

The manufacturing process of glass fibers used for the reinforcement of composite material consists in drawing a glass melt at high temperature through the bushing plate into fibers using a winder. This process is sensitive to numerous disturbances that can cause the fiber to break during the drawing process. In order to understand the origin of these failures and improve the process efficiency, it is important to understand the physics of the forming fiber. We investigate here the underlying physics of the forming of a single fiber through numerical simulations. In particular, we focus on the region from the hole tips at the bushing plate to the glass transition point. The influence of key parameters (e.g. operating windows, and heat transfers mechanisms) on the fiber radius attenuation and the internal stresses is investigated through a sensitivity analysis. In addition, the impact of the temperature variations at the bushing plate is investigated. Finally, we show how the forming stress is influenced by these parameters. It is found that the internal stress can be minimizing by varying the operating windows. On the other hand, results also demonstrate that the heat pattern of the bushing plate is one of the most important causes for disturbance in the process. [less ▲]

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See detailNumerical investigation of continuous fiber glass process
Chouffart, Quentin ULiege; Simon, Philippe; Terrapon, Vincent ULiege

Conference (2014, May)

The manufacturing process of glass fibers used for the reinforcement of composite material consists in drawing a glass melt at high temperature through an array of thousands of small orifices (i.e. the ... [more ▼]

The manufacturing process of glass fibers used for the reinforcement of composite material consists in drawing a glass melt at high temperature through an array of thousands of small orifices (i.e. the bushing plate) into fibers using a winder. This process is sensitive to numerous disturbances that can cause the fiber to break during the drawing process. In order to understand the origin of these failures and improve the process efficiency, it is important to understand the physics of the forming fiber. Unlike other glass forming processes, this process is characterized by a high cooling rate. As a consequence, the heat transfers have a strong influence on the fiber forming behavior. We study here the heat transfer mechanisms through numerical simulations of one single fiber. Several key parameters are presented through sensitive analysis (e.g. influence of the material emissivity, surrounding environment, process parameters). These studies are linked to measurements obtained from a dedicated experimental unit. In addition, the impact of the temperature variations at the bushing plate is investigated. Finally, we show how the forming stress is influenced by these parameters. It is found that convection by air entrainment around the fiber and thus the environment conditions represent a critical contribution to the cooling rate. On the other hand, results also demonstrate that the heat pattern of the bushing plate is one of the most important causes for disturbance in the process. [less ▲]

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See detailElasto-inertial turbulence in polymeric flows
Terrapon, Vincent ULiege; Dubief, Yves; Soria, Julio

Conference (2013, November 26)

The dynamics of elasto-inertial turbulence (EIT) is investigated numerically from the perspective of the coupling between polymer dynamics and flow structures. In particular, direct numerical simulations ... [more ▼]

The dynamics of elasto-inertial turbulence (EIT) is investigated numerically from the perspective of the coupling between polymer dynamics and flow structures. In particular, direct numerical simulations of channel flow with Reynolds numbers ranging from 1000 to 6000 are used to study the formation and dynamics of elastic instabilities and their effects on the flow. Based on the splitting of the pressure into inertial and polymeric contributions, it is shown that the trains of cylindrical structures around thin sheets of high polymer extension that are characteristics to elasto-inertial turbulence are mostly driven by polymeric contributions. [less ▲]

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See detailOn the mechanism of elasto-inertial turbulence
Dubief, Yves; Terrapon, Vincent ULiege; Soria, Julio

in Physics of Fluids (2013), 25(110817), 1-16

Elasto-inertial turbulence (EIT) is a new state of turbulence found in inertial flows with polymer additives. The dynamics of turbulence generated and controlled by such additives is investigated from the ... [more ▼]

Elasto-inertial turbulence (EIT) is a new state of turbulence found in inertial flows with polymer additives. The dynamics of turbulence generated and controlled by such additives is investigated from the perspective of the coupling between polymer dynamics and flow structures. Direct numerical simulations of channel flow with Reynolds numbers ranging from 1000 to 6000 (based on the bulk and the channel height) are used to study the formation and dynamics of elastic instabilities and their effects on the flow. The flow topology of EIT is found to differ significantly from Newtonian wall-turbulence. Structures identified by positive (rotational flow topology) and negative (extensional/compressional flow topology) second invariant Qa isosurfaces of the velocity gradient are cylindrical and aligned in the spanwise direction. Polymers are significantly stretched in sheet-like regions that extend in the streamwise direction with a small upward tilt. The Qa cylindrical structures emerge from the sheets of high polymer extension, in a mechanism of energy transfer from the fluctuations of the polymer stress work to the turbulent kinetic energy. At subcritical Reynolds numbers, EIT is observed at modest Weissenberg number (Wi, ratio polymer relaxation time to viscous time scale). For supercritical Reynolds numbers, flows approach EIT at large Wi. EIT provides new insights on the nature of the asymptotic state of polymer drag reduction (maximum drag reduction), and explains the phenomenon of early turbulence, or onset of turbulence at lower Reynolds numbers than for Newtonian flows observed in some polymeric flows. [less ▲]

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See detailDynamics of Elasto-Inertial Turbulence in Flows with Polymer Additives
Terrapon, Vincent ULiege; Dubief, Yves; Soria, Julio

in Proceedings of the 8th International Symposium on Turbulence and Shear Flow Phenomena (TSFP-8) (2013, August 30)

The dynamics of elasto-inertial turbulence is investigated numerically from the perspective of the coupling between polymer dynamics and flow structures. In particular, direct numerical simulations of ... [more ▼]

The dynamics of elasto-inertial turbulence is investigated numerically from the perspective of the coupling between polymer dynamics and flow structures. In particular, direct numerical simulations of channel flow with Reynolds numbers ranging from 1000 to 6000 are used to study the formation and dynamics of elastic instabilities and their effects on the flow. Based on the splitting of the pressure into inertial and polymeric contributions, it is shown that the trains of cylindrical structures around sheets of high polymer extension that are characteristics to elasto-inertial turbulence are mostly driven by polymeric contributions. [less ▲]

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See detailTorsional flutter of bluff bodies
Terrapon, Vincent ULiege; Guissart, Amandine ULiege; Andrianne, Thomas ULiege et al

Scientific conference (2013, July 15)

Detailed reference viewed: 68 (22 ULiège)
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See detailNumerical and experimental investigation of fiber drawing process
Chouffart, Quentin ULiege; Simon, Philippe; Terrapon, Vincent ULiege

Conference (2013, July 05)

The manufacturing process of glass fibers used for the reinforcement of composite material consists in drawing liquid glass at high temperature into fibers. This process is very complex and sensitive to ... [more ▼]

The manufacturing process of glass fibers used for the reinforcement of composite material consists in drawing liquid glass at high temperature into fibers. This process is very complex and sensitive to numerous disturbances that can cause the breaking of the forming fibers. Breaks have a strong negative impact on the process efficiency. It is thus very important to understand the mechanisms of fiber breaking in order to optimize the manufacturing process. As a first step towards elucidating the causes of these failures, we investigate here the underlying physics of the forming of a single fiber through numerical simulations. In particular, we focus on the region from the hole tips at the bushing plate to the glass transition point. The influence of key parameters (e.g., glass flow rate, drawing velocity, external environment, glass properties) on the fiber radius attenuation and the internal stresses is investigated through a sensitivity analysis. Finally, these numerical studies are compared with experimental data measurements obtained from a dedicated fiberization unit for a single fiber. These experimental results also serve as additional insight into the forming process and as validation of the physical models, such as glass rheology or heat transfers. Comparisons between numerical and experimental results show a good agreement and demonstrate that simulations can provide a useful tool to gain insight into the underlying physics and to devise new strategies for adjusting the process operating window. [less ▲]

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See detailUsing Proper Orthogonal Decomposition and Dynamic Mode Decomposition Methods for Comparing CFD Results Experimental Measurements
Guissart, Amandine ULiege; Andrianne, Thomas ULiege; Dimitriadis, Grigorios ULiege et al

in Proceedings of the 15th International Forum on Aeroelasticity and Structural Dynamics, IFASD 2013 (2013, June 26)

A method for the quantitative comparison of numerical and/or experimental data of unsteady aerodynamics around static and oscillating bodies is introduced. It is based on Proper Orthogonal Decomposition ... [more ▼]

A method for the quantitative comparison of numerical and/or experimental data of unsteady aerodynamics around static and oscillating bodies is introduced. It is based on Proper Orthogonal Decomposition (POD) and Dynamic Mode Decomposition (DMD) to extract the dominant structures of the unsteady flow. The proposed method is applied to spatio-temporal data for the flow around a 4:1 rectangular cylinder. Exper- imental data are obtained from wind tunnel testing and two dimensional Time-resolved Particle Image Velocimetry (Tr-PIV) measurements, while unsteady Reynolds Averaged Navier-Stokes (uRANS) are used to compute numerical results. It is demonstrated that the two approaches are complementary and represent a powerful tool that enables the analysis and the quantitative comparison of the main spatial (POD) and temporal (DMD) characteristics of unsteady aerodynamic data. [less ▲]

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See detailNumerical investigation of continuous fiber glass drawing
Chouffart, Quentin ULiege; Simon, Philippe; Terrapon, Vincent ULiege

in Idelsohn, Sergio R; Papadrakakis, Manolis; Schrefler, Bernhard A (Eds.) Proceedings of the V International Conference on Computational Methods for Coupled Problems in Science and Engineering (2013, June)

The physics of glass fiber drawing is studied through numerical simulations and experimental measurements, with a focus on the fluid region, from the hole tip at the bushing plate to the glass transition ... [more ▼]

The physics of glass fiber drawing is studied through numerical simulations and experimental measurements, with a focus on the fluid region, from the hole tip at the bushing plate to the glass transition point. The influence of the different heat transfer mechanisms is investigated to understand their respective impact on fiberization, such as fiber radius attenuation and internal stresses. Numerical predictions are then compared to experimental data measurements obtained from a dedicated fiberization unit. Numerical and experimental results show a good agreement. In particular, it is found that the ambient air temperature and the radiation have an important impact on the fiber cooling rate. Moreover, for a prescribed fiber diameter, internal stresses are lower when operating at a higher temperature. [less ▲]

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See detailDevelopment of advanced models for transition to turbulence in hypersonic flows and prediction of transition under uncertainties
Serino, Gennaro ULiege; Terrapon, Vincent ULiege; Magin, Thierry et al

in Serino, Gennaro (Ed.) Review of the VKI Doctoral Research 2012-2013 (2013, March)

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See detailIntegrating Experimental and Computational Fluid Dynamics approaches using Proper Orthogonal Decomposition Techniques
Andrianne, Thomas ULiege; Yasue, Kanako; Guissart, Amandine ULiege et al

in Progress in Aerospace Sciences (2013)

The concept of Proper Orthogonal Decomposition (POD) is used to integrate Experimental Fluid Dynamics (EFD) and Computational Fluid Dynamics (CFD) approaches. The key idea is to take advantage of the ... [more ▼]

The concept of Proper Orthogonal Decomposition (POD) is used to integrate Experimental Fluid Dynamics (EFD) and Computational Fluid Dynamics (CFD) approaches. The key idea is to take advantage of the optimality of the POD technique and its capability to extract the most energetic patterns of complex aerodynamic flow fields. First, the concept of Modal Assurance Criterion (MAC) is used to obtain a simple quantitative criterion to compare EFD measurements to CFD results. The comparison is based on the POD modes, extracted from each set of data. The analysis of the energy content of the modes allows to draw important conclusions about the role of the latter. The method is applied in the study of the flow field around a rectangular cylinder, which is either static or oscillating in a low-speed flow field. The second EFD/CFD integration technique deals with the reconstruction of a flow field from measured data, making use of CFD simulation results. The POD modes are first extracted from several CFD data sets, using a snapshot POD approach. Then the entire flow field of measured data can be reconstructed using a gappy POD method. The technique is applied to the transonic flow around a civil aircraft type wind tunnel model. The EFD measurements consist in pressure coefficient data from pressure ports or pressure-sensitive paint. It is shown that the complete flow field can be reconstructed from the pressure data with satisfactory accuracy and at relatively low computational cost. The work demonstrates the potential of the POD technique to integrate EFD and CFD data, leading to a combined, validated and complete analysis of the flow under consideration. [less ▲]

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