References of "Terrapon, Vincent"
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See detailUnsteady pressure distributions on a 4:1 rectangular cylinder: comparison of numerical and experimental results using decomposition methods.
Guissart, Amandine ULiege; Andrianne, Thomas ULiege; Dimitriadis, Grigorios ULiege et al

Conference (2017, July 04)

Detached flows around bluff bodies are ubiquitous in civil engineering applications. In this work, the flow around a static 4:1 rectangular cylinder at moderate Reynolds number and at different angles of ... [more ▼]

Detached flows around bluff bodies are ubiquitous in civil engineering applications. In this work, the flow around a static 4:1 rectangular cylinder at moderate Reynolds number and at different angles of incidence is studied using both Experimental Fluid Dynamics (EFD) and Computational Fluid Dynamics (CFD). Typically, the integration of EFD and CFD allows a better understanding of the flow of interest by leveraging the complementary of their respective outputs. However, the comparison of computational and experimental results is an important but difficult step of this integration, particularly in the case of local quantities related to unsteady flows. In this work, decomposition methods are used to compare unsteady loads and pressure distributions coming from EFD and CFD. In particular, Proper Orthogonal Decomposition (POD) and Dynamic Mode Decomposition (DMD) are used to extract the dominant structures of the aerodynamic coefficients. The experimental data are obtained from dynamic pressure measurements in wind tunnel while numerical data come from two-dimensional unsteady Reynolds-Averaged Navier-Stokes (uRANS) simulations and tri-dimensional Delayed-Detached Eddy Simulations (DDES). This work shows that the decomposition methods represent a powerful tool enabling the analysis and the quantitative comparison of the main spatial and temporal characteristics of unsteady flows. Moreover, the accuracy of uRANS and DDES results is analyzed in light of the capacity of both CFD techniques to capture the reattachment occurring on the upper part of the rectangular cylinder. [less ▲]

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See detailResearch on Fast Aeroelastic Modeling Methods for the Transonic Regime
Güner, Hüseyin ULiege; Dimitriadis, Grigorios ULiege; Terrapon, Vincent ULiege

in Proceedings of the International Forum on Aeroelasticity and Structural Dynamics, IFASD 2017 (2017, June 27)

Two methods for modeling unsteady transonic flows at low computational cost are presented as a first step towards a fast and accurate aeroelastic calculation methodology for the preliminary design stage ... [more ▼]

Two methods for modeling unsteady transonic flows at low computational cost are presented as a first step towards a fast and accurate aeroelastic calculation methodology for the preliminary design stage in the transonic flow regime. The first approach corresponds to a quasi-steady approximation based on few steady simulations that is improved through the use of an unsteady filter. The second approach is based on the interpolation of dynamic modes between solutions at different frequencies that are obtained either from Dynamic Mode Decomposition (DMD) of unsteady simulations or directly from Harmonic Balance (HB) simulations. The two methods are illustrated in the case of a pitching airfoil in the transonic regime. Results show that the first method is fast and provides a first approximation of the unsteady dynamics. The computational cost of the second approach is higher, but the method provides better results in predicting aerodynamic forces and shock motion for a large range of reduced frequencies. [less ▲]

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See detailStaggered strong coupling between existing fluid and solid solvers through a Python interface for fluid-structure interaction problems
Thomas, David ULiege; Variyar, Anil; Boman, Romain ULiege et al

in Proceedings of the VII International Conference on Coupled Problems in Science and Engineering (2017, June)

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See detailPIV-based estimation of unsteady loads on a flat plate at high angle of attack using momentum equation approaches
Guissart, Amandine ULiege; Bernal, Luis; Dimitriadis, Grigorios ULiege et al

in Experiments in Fluids (2017), 58(5), 53

This work presents, compares and discusses results obtained with two indirect methods for the cal culation of aerodynamic forces and pitching moment from 2D Particle Image Velocimetry (PIV) measurements ... [more ▼]

This work presents, compares and discusses results obtained with two indirect methods for the cal culation of aerodynamic forces and pitching moment from 2D Particle Image Velocimetry (PIV) measurements. Both methodologies are based on formulations of the momentum balance: the integral Navier-Stokes equations and the “flux equation” proposed by Noca et al. (1999), which has been extended to the computation of moments. The indirect methods are applied to spatio-temporal data for different separated flows around a plate with a 16:1 chord-to-thickness ratio. Experimental data are obtained in a water channel for both a plate undergoing a large amplitude imposed pitching motion and a static plate at high angle of attack. In addition to PIV data, direct measurements of aerodynamic loads are carried out to assess the quality of the indirect calculations. It is found that indirect methods are able to compute the mean and the temporal evolution of the loads for two-dimensional flows with a reasonable accuracy. Nonetheless, both methodologies are noise sensitive and, the parameters impacting the computation should thus be chosen carefully. It is also shown that results can be improved through the use of Dynamic Mode Decomposition (DMD) as a pre-processing step. [less ▲]

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See detailAssessment of the fluid-structure interaction capabilities for aeronautical applications of the open-source solver SU2.
Sanchez, Ruben; Kline, Heather; Thomas, David ULiege et al

in Proceedings of the VII European Congress on Computational Methods in Applied Science and Engineering (2016, September)

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See detailFree-slip boundary conditions for simulating free-surface incompressible flows through the Particle Finite Element Method
Cerquaglia, Marco Lucio ULiege; Deliège, Geoffrey ULiege; Boman, Romain ULiege et al

in International Journal for Numerical Methods in Engineering (2016)

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See detailNumerical and experimental study of the glass flow and heat transfer in the continuous glass fiber drawing process
Chouffart, Quentin ULiege; Simon, Philippe; Terrapon, Vincent ULiege

in Journal of Materials Processing Technology (2016)

The manufacturing process of glass fibers used for the reinforcement of composite materials consistsin drawing a free jet of a molten glass at high temperature into fibers using a winder. This process is ... [more ▼]

The manufacturing process of glass fibers used for the reinforcement of composite materials consistsin drawing a free jet of a molten glass at high temperature into fibers using a winder. This process is sensitive to numerous disturbances that can cause the fiber to break during the drawing process, and thus reduce the process efficiency. The underlying physics of the forming of a single fiber is investigated here through numerical simulations, and results are validated with measurements obtained on a dedicated experimental unit. Both a two-dimensional axisymmetric and a simplified one-dimensional model are used to simulate the high-temperature region before glass transition. The influence of key parameters and physical mechanisms on the internal stress is investigated through a sensitivity analysis. The simplified model is then used to identify the optimal operating window and to assess the impact of temperature inhomogeneities at the bushing plate. Results show that the initial region close to the tip is critical, and that a low cooling rate reduces the stress. Operating at high tip temperature, large drawing velocity and small tip radius is then found to be the best strategy to minimize the stress. Finally, it is shown 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 detailPIV-based estimation of unsteady loads on a flat plate at high angle of attack using momentum equation approaches
Guissart, Amandine ULiege; Bernal, Luis; Dimitriadis, Grigorios ULiege et al

Conference (2015, November 23)

The direct measurement of loads with force balance can become challenging when the forces are small or when the body is moving. An alternative is the use of Particle Image Velocimetry (PIV) velocity ... [more ▼]

The direct measurement of loads with force balance can become challenging when the forces are small or when the body is moving. An alternative is the use of Particle Image Velocimetry (PIV) velocity fields to indirectly obtain the aerodynamic coefficients. This can be done by the use of control volume approaches which lead to the integration of velocities, and other fields deriving from them, on a contour surrounding the studied body and its supporting surface. This work exposes and discusses results obtained with two different methods: the direct use of the integral formulation of the Navier-Stokes equations and the so-called Noca's method. The latter is a reformulation of the integral Navier-Stokes equations in order to get rid of the pressure. Results obtained using the two methods are compared and the influence of different parameters is discussed. The methods are applied to PIV data obtained from water channel testing for the flow around a 16:1 plate. Two cases are considered: a static plate at high angle of attack and a large amplitude imposed pitching motion. Two-dimensional PIV velocity fields are used to compute the aerodynamic forces. Direct measurements of dynamic loads are also carried out in order to assess the quality of the indirectly calculated coefficients. [less ▲]

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See detailUsing 2D-PIV measurements to compute unsteady aerodynamic loads on a flat plate at high angle of attack
Guissart, Amandine ULiege; Bernal, Luis; Dimitriadis, Grigorios ULiege et al

in Proceedings of the 16th International Forum on Aeroelasticity and Structural Dynamics, IFASD 2015 (2015, June 30)

This work exposes and discusses results obtained for aerodynamic forces using an indirect calculation based on Particle Image Velocimetry (PIV) measurements. The methodology used is based on the integral ... [more ▼]

This work exposes and discusses results obtained for aerodynamic forces using an indirect calculation based on Particle Image Velocimetry (PIV) measurements. The methodology used is based on the integral formulation of the Navier-Stokes equations and is applied to spatio-temporal data for different flows around a plate with a 16:1 chord-to-thickness ratio at high angle of attack. Experimental data are obtained in a water channel for both a static and a pitching plate. In addition to PIV data, direct measurements of aerodynamic loads are carried out to assess the quality of the indirect calculation. It is demonstrated that this indirect method is able to compute the mean and the temporal evolution of the lift and drag coefficients with a reasonable accuracy. It is also shown that the noise sensitivity of the method can be partly alleviated through the use of Dynamic Mode Decomposition (DMD) as a pre-processing step to smooth the spatio-temporal data. [less ▲]

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See detailDirect Numerical Simulation of Mixed Convection in Turbulent Channel Flow: On the Reynolds number dependency of momentum and heat transfer under unstable stratification
Sid, Samir ULiege; Dubief, Yves; Terrapon, Vincent ULiege

in Proceedings of the 8th International Conference on Computational Heat and Mass Transfer, ICCHMT 2015 (2015, May 27)

Direct numerical simulations of unstably stratified turbulent channel flow have been performed in order to investigate the Reynolds number effect on mixed convection. Six different cases are considered ... [more ▼]

Direct numerical simulations of unstably stratified turbulent channel flow have been performed in order to investigate the Reynolds number effect on mixed convection. Six different cases are considered with friction Reynolds number Re_\tau =180 and 395 and friction Richardson number Ri_\tau = 0, 100 and 1000. It is shown that both friction coefficient and Nusselt number increase under unstable stratification for a sufficiently large Richardson number. At low Richardson number, the friction coefficient can either increase or decrease depending on the Reynolds number. The drag reduction is associated with an increase of mean velocity due to an enhanced dissipation of Reynolds shear stress by pressure strain in the buffer region. The breakdown of the Reynolds analogy is demonstrated as the turbulent Prandtl number exhibits a non-constant behavior due to buoyancy. [less ▲]

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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)

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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)

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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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