References of "Guissart, Amandine"
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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 detailNumerical and Experimental Study of Bluff Body Aerodynamics
Guissart, Amandine ULiege

Doctoral thesis (2017)

This thesis investigates the dynamics of detached flows around bluff bodies and the resulting aerodynamic loads, which are of primary importance in wind engineering. Two canonical geometries are ... [more ▼]

This thesis investigates the dynamics of detached flows around bluff bodies and the resulting aerodynamic loads, which are of primary importance in wind engineering. Two canonical geometries are considered: a 4:1 rectangular cylinder and a flat plate that is either fixed at large incidence or undergoing a large pitching motion. The different studies are conducted through both experimental measurements and numerical simulations. Their results are compared by using Proper Orthogonal Decomposition and Dynamic Mode Decomposition. The flow around the 4:1 rectangular cylinder is studied through dynamic pressure measurements along a cross-section combined with Unsteady Reynolds-Averaged Navier-Stokes (RANS) and Delayed-Detached Eddy Simulation (DDES) results. The main objectives are two-fold: i) to improve the general knowledge about the spatio-temporal flow features, the resulting aerodynamic loads, and their variations with the incidence angle and the freestream velocity, and ii) to assess the capabilities of RANS and DDES approaches to provide a sufficiently accurate estimation of the flow and aerodynamic loads at several incidences. It is shown that the rectangular cylinder involves complex separation-reattachment phenomena that are highly sensitive to the Reynolds number (Re). Consequently, the mean lift slope increases rapidly in the investigated range of Re numbers. Additionally, it is shown that both RANS and DDES simulations fail to accurately approximate the flow at the different incidence angles considered. Only the RANS approach is able to qualitatively estimate the spatio-temporal variations of vortices for incidences below the stall angle. Nonetheless, this stall angle is only captured by DDES. The flows around a flat plate with different configurations are selected as test cases to assess an indirect load measurement technique that uses Particle Image Velocimetry (PIV) velocity fields. This technique is well suited to analyze phenomena involving moving bodies where direct load measurements could be contaminated by the structural response. The capabilities of two formulations based on the momentum balance are tested. The first method uses the integral form of the Navier-Stokes equation (INSE), and the second is based on the flux equation derived by Noca et al (1999) (NOCA). This second method is extended to the indirect estimation of aerodynamic moments that is not provided by the original formulation. The user-defined parameters required by the INSE and NOCA methods are studied to evaluate their effects on the indirect estimation. Additionally, numerical results are used to better understand the limitations of the indirect approaches. It is shown that the INSE and the NOCA methods perform similarly for the detached flows considered. They are able to accurately estimate the mean loads, and the phase-averaged time responses are also estimated with a reasonable accuracy as long as the corresponding PIV phase-averaged fields are sufficiently converged. The unsteady results are generally negatively impacted by three-dimensional effects and the lack of a clear single shedding frequency. The user-defined parameters that have the most significant effects on the accuracy of the indirect load estimations are identified and guidelines for their setting are proposed. Overall, this thesis demonstrates the added-value of integrating numerical and experimental studies, especially in the context of wind engineering where the aerodynamics of bluff civil engineering structures is very challenging to study numerically. The two approaches are complementary and enable a deeper understanding of the physics. [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

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 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 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: 84 (27 ULiège)
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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: 75 (22 ULiège)
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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 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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See detailUsing Proper Orthogonal Decomposition Methods for Comparing CFD Results to Experimental Measurements
Andrianne, Thomas ULiege; Guissart, Amandine ULiege; Terrapon, Vincent ULiege et al

Scientific conference (2012, December 07)

This work presents a method for quantitative comparison of numerical results to experimental measurements. It is based on the concept of Proper Orthogonal Decomposition. This technique is selected in ... [more ▼]

This work presents a method for quantitative comparison of numerical results to experimental measurements. It is based on the concept of Proper Orthogonal Decomposition. This technique is selected in order to compare the unsteady aerodynamic flows around static and oscillating bodies obtained from wind tunnel testing and numerical simulations. Two dimensional Time-resolved Particle Image Velocimetry measurements are carried out on the upper surface a 4:1 rectangular cylinder. Simulations are performed using unsteady Reynolds-Averaged Navier-Stokes and an unsteady Discrete Vortex Method. It is demonstrated that the proposed technique is a good preliminary step for comparing the main characteristics of unsteady aerodynamic data. [less ▲]

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See detailUsing Proper Orthogonal Decomposition Methods for Comparing CFD Results to Experimental Measurements
Andrianne, Thomas ULiege; Guissart, Amandine ULiege; Terrapon, Vincent ULiege et al

in Proceedings of the 5th Symposium on Integrating CFD and Experiments in Aerodynamics (Integration 2012) (2012, October 03)

This work presents a method for quantitative comparison of numerical results to experimental measurements. It is based on the concept of Proper Orthogonal Decomposition. This technique is selected in ... [more ▼]

This work presents a method for quantitative comparison of numerical results to experimental measurements. It is based on the concept of Proper Orthogonal Decomposition. This technique is selected in order to compare the unsteady aerodynamic flows around static and oscillating bodies obtained from wind tunnel testing and numerical simulations. Two dimensional Time-resolved Particle Image Velocimetry measurements are carried out on the upper surface a 4:1 rectangular cylinder. Simulations are performed using unsteady Reynolds-Averaged Navier-Stokes and an unsteady Discrete Vortex Method. It is demonstrated that the proposed technique is a good preliminary step for comparing the main characteristics of unsteady aerodynamic data. [less ▲]

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See detailPré-dimensionnement d’un UAV : Partie aérodynamique
Guissart, Amandine ULiege

Master's dissertation (2011)

Detailed reference viewed: 112 (7 ULiège)