References of "Andrianne, Thomas"
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See detailFirst passage time as an analysis tool in experimental wind engineering [under review]
Vanvinckenroye, Hélène ULiege; Andrianne, Thomas ULiege; Denoël, Vincent ULiege

in Journal of Wind Engineering & Industrial Aerodynamics (in press)

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See detailMixture model in high-order statistics for peak factor estimation on low-rise building
Rigo, François ULiege; Andrianne, Thomas ULiege; Denoël, Vincent ULiege

Scientific conference (2018, December 10)

To design reliable structures, extreme pressures and peak factors are required. In many applications of Wind Engineering, their statistical analysis has to be performed taking into account the non ... [more ▼]

To design reliable structures, extreme pressures and peak factors are required. In many applications of Wind Engineering, their statistical analysis has to be performed taking into account the non-Gaussianity of the wind pressures. With the increasing precision and sampling frequency of pressure sensors, large short and local peak events are more usually captured. Their relevance is naturally questioned in the context of a structural design. Furthermore, the increasing computational power allows for accumulation and analysis of larger data sets revealing the detailed nature of wind flows around bluff bodies. In particular, in the shear layers and where local vortices form, it is commonly admitted that the Probability Density Function (PDF) of measured pressures might exhibit two or more significant components. These mixed flows can be modelled with mixture models [Cook (2016)]. Whenever several processes coexist, and when one of them is leading in the tail of the statistical distribution, as will be seen next in the context of corner vortices over a flat roof, it is natural to construct the extreme value model with this leading process and not with the mixed observed pressures. It is therefore important to separate the different processes that can be observed in the pressure histories. Once this is done, specific analytical formulations of non-Gaussian peak factors can be used to evaluate the statistics of extreme values [Kareem and Zhao (1994), Chen (2009)]. The separation of mixed processes is usually done by means of the PDF of the signals [Cook (2016)]. This information is of course essential to perform an accurate decomposition but it might be facilitated by considering higher rank information like auto-correlations and higher correlations like the triple or quadruple correlation. Indeed, the two phenomena that need to be separated and identified might be characterized by significantly different timescales, which are not reflected in the PDF. In this paper, the large negative pressures measured on a flat roof are analyzed and decomposed into two elementary processes, namely, the flapping corner vortex and the turbulent flow detaching from the sharp upstream edge. The full paper will finally show that an accurate decomposition of the recorded pressures into their underlying modes provides a more meaningful evaluation of the extreme pressures. [less ▲]

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See detailVIV response of a suspended sphere nearby the critical Reynolds number
Andrianne, Thomas ULiege; Rigo, François ULiege; Denoël, Vincent ULiege

Scientific conference (2018, September 10)

The Vortex-Induced Vibration of a sphere connected to a flexible beam is investigated in air for Reynolds numbers including the critical value. For this value (ReC =3e5 ), wake disorganisation is expected ... [more ▼]

The Vortex-Induced Vibration of a sphere connected to a flexible beam is investigated in air for Reynolds numbers including the critical value. For this value (ReC =3e5 ), wake disorganisation is expected in a static configuration. This fundamental fluid-structure interaction characterised by an axisymmetric configuration leads to vibrations in the lateral and longitudinal directions. Similarly to the well-known circular cylinder, a lock-in phenomenon will take place due to the effect of the motion of the body on the shedding process. An experimental aeroelastic model is designed, instrumented and tested in the wind tunnel of University of Liège. The objective is twofold: (i) solve a practical wind-engineering problem (a spherical suspended streetlight) and (ii) propose a fundamental investigation of the VIV of a smooth sphere for sub-critical and critical Reynolds numbers. [less ▲]

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See detailVortex induced vibrations of rectangular cylinders arranged on a grid
Rigo, François ULiege; Andrianne, Thomas ULiege

Scientific conference (2018, September 10)

A grid arrangement made of one hundred rectangular cylinders fixed to the facade of a house generates strong and disturbing mono-harmonic noise. The cross-flow vibration of the rectangular cylinders is ... [more ▼]

A grid arrangement made of one hundred rectangular cylinders fixed to the facade of a house generates strong and disturbing mono-harmonic noise. The cross-flow vibration of the rectangular cylinders is identified as the origin of the noise. The present article proposes a complete investigation of the Vortex Induced Vibration (VIV) combined with a grid effect. It is based on in situ measurements, numerical (finite elements and Computational Fluid Dynamics (CFD)) and extensive wind tunnel (WT) modelling. A comparison between unsteady pressure tap measurements and CFD results allows to understand the vortex shedding process and synchronisation type depending on the wind incidence and spacing of the cylinders. On the basis of this multi-approach parametric investigation, a deep understanding of the VIV-grid phenomenon enables to propose two mitigation techniques. These techniques are tested and their effectiveness is reported in terms of vibration amplitude and acoustic intensity. [less ▲]

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See detailEnergy harvesting from different aeroelastic instabilities of a square cylinder
Andrianne, Thomas ULiege; Aryoputro, Renar; Laurent, Philippe ULiege et al

in Journal of Wind Engineering & Industrial Aerodynamics (2018), 172

This paper presents an experimental and numerical investigation of the power extraction from the oscillations of a square beam due to aeroelastic instabilities. The energy harvesting is performed using a ... [more ▼]

This paper presents an experimental and numerical investigation of the power extraction from the oscillations of a square beam due to aeroelastic instabilities. The energy harvesting is performed using a coil-magnet arrangement connected to a variable resistance load with the target objective to auto-power a remote sensor. Two aeroelastic phenomena are investigated: Vortex Induced Vibration (VIV) and cross-flow galloping. The first instability (VIV) is analyzed on a free-standing vertical structure. A second experimental set-up is developed on a horizontal square cylinder supported by springs, free to oscillate vertically as a rigid body. In this case, both galloping and VIV interact, leading to interesting characteristics in order to harvest energy from the wind. The behavior of each electro-mechanical aeroelastic system is investigated for different reduced wind speeds and load resistances in a wind tunnel. Observed efficiencies are rather low, but large enough to power a remote sensor with an adapted measuring strategy. Both harvesting systems are then studied numerically using a wake oscillator model (for VIV) coupled to a quasi-steady model (for galloping) and an electric model (for the harvester). This mathematical model is used to extend the parametric space and to highlight the effectiveness of the high stable branch of the VIV-galloping curve to harvest energy. [less ▲]

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See detailImproving CFD prediction of drag on Paralympic tandem athletes: influence of grid resolution and turbulence model
Mannion, Paul; Toparlar, Yasin; Blocken, Bert et al

in Sports Engineering (2017)

Tandem cycling enables visually impaired athletes to compete in cycling in the Paralympics. Tandem aerodynamics can be analysed by track measurements, wind-tunnel experiments and numerical simulations ... [more ▼]

Tandem cycling enables visually impaired athletes to compete in cycling in the Paralympics. Tandem aerodynamics can be analysed by track measurements, wind-tunnel experiments and numerical simulations with computational fluid dynamics (CFD). However, the proximity of the pilot (front) and the stoker (rear) and the associated strong aerodynamic interactions between both athletes present substantial challenges for CFD simulations, the results of which can be very sensitive to computational parameters such as grid topology and turbulence model. To the best of our knowledge, this paper presents the first CFD and wind-tunnel investigation on tandem cycling aerodynamics. The study analyses the influence of the CFD grid topology and the turbulence model on the aerodynamic forces on pilot and stoker and compares the results with wind-tunnel measurements. It is shown that certain combinations of grid topology and turbulence model give trends that are opposite to those shown by other combinations. Indeed, some combinations provide counterintuitive drag outcomes with the stoker experiencing a drag force up to 28% greater than the pilot. Furthermore, the application of a blockage correction for two athlete bodies in close proximity is investigated. Based on a large number of CFD simulations and validation with wind-tunnel measurements, this paper provides guidelines for the accurate CFD simulation of tandem aerodynamics. [less ▲]

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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 detailEnergy harvesting from galloping of prisms: A wind tunnel experiment
Hémon, Pascal; Amandolèse, Xavier; Andrianne, Thomas ULiege

in Journal of Fluids & Structures (2017), 70

We study the energy harvesting from the galloping oscillations of rigid prisms flexibly mounted in a wind tunnel. A square section and a 2/3 rectangular section are tested and the inclination angle of the ... [more ▼]

We study the energy harvesting from the galloping oscillations of rigid prisms flexibly mounted in a wind tunnel. A square section and a 2/3 rectangular section are tested and the inclination angle of the prisms referred to the flow direction is optimally adapted. The energy harvester is based on magnets moving with the prism in the front of a coil-core at rest. Energy is dissipated in a load resistance for which an optimal value is found. Efficiency of the "prism wind turbine" is weak compared to usual wind turbine due to the physics of the galloping mechanism. However such systems remain interesting for their potential of adaptation to various situations. [less ▲]

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See detailReal-scale observations of vortex induced vibrations of stay-cables in the boundary layer
Denoël, Vincent ULiege; Andrianne, Thomas ULiege

in Procedia Engineering (2017), 199

Abstract This paper shows some records and analysis of evidences of vortex induced vibrations of very long stay cables in the atmospheric boundary layer. The considered structure is a 254-m high ... [more ▼]

Abstract This paper shows some records and analysis of evidences of vortex induced vibrations of very long stay cables in the atmospheric boundary layer. The considered structure is a 254-m high telecommunication antenna whose structural system is made of a light flexible metallic truss, approx. 10×10m square, which is stayed at five different levels by a set of 20 pairs of stay-cables. The exposure of this antenna is category I with a low-turbulence wind flow which results in a high sensitivity to vortex induced vibrations. The fundamental frequency of the longest cable is 0.3 Hz so that several dozens of regularly spaced natural frequencies could be observed with a sampling frequency of 500 Hz. Sufficiently long recordings allowed to distinctly observe the separate peaks corresponding to the various modes of the cables. Among them many are excited by the detachment of vortices, taking place at different frequencies (because of different cable diameters and the change of wind velocity along the height of the antenna) in the range 35-55 Hz. Referring to the so-called spectral model proposed by Vickery and Clark, the detachment of vortices takes place in a certain bandwidth, whose extent is not completely understood yet. This bandwidth is clearly observed with our long stay-cables because of the large density of mode shapes in the range [0, 200] Hz and because of their regular spacing in the spectral domain. To the author’s knowledge this constitutes a first attempt at identifying this parameter of the Vickery and Clark model from full-scale measurements. [less ▲]

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See detailReal-scale observations of vortex induced vibrations of stay-cables in the boundary layer
Denoël, Vincent ULiege; Andrianne, Thomas ULiege

in Proceedings of the Xth International conference on Structural Dynamics (2017)

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See detailSTOCHASTIC STABILITY OF A TOWER CRANE UNDER GUSTY WINDS
Vanvinckenroye, Hélène ULiege; Andrianne, Thomas ULiege; Denoël, Vincent ULiege

in Proceedings of the 7th European-African Conference on Wind Engineering (2017)

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See detailAssessment of extreme value overestimations with equivalent static wind loads
Blaise, Nicolas ULiege; Andrianne, Thomas ULiege; Denoël, Vincent ULiege

in Journal of Wind Engineering & Industrial Aerodynamics (2017)

The wind-resistant design using equivalent static wind loads is convenient for structural engineers. This paper studies the reliability of such an approach in the case of non-Gaussianities in both ... [more ▼]

The wind-resistant design using equivalent static wind loads is convenient for structural engineers. This paper studies the reliability of such an approach in the case of non-Gaussianities in both aerodynamic pressures and responses. These non-Gaussianities are responsible for overestimations of envelope values and may result in uneconomical designs, if not appropriately understood, assessed and addressed. In this study, it is shown that the equivalent static wind loads defined with the Conditional Expected Load method, which extends the physical meaning of the Load-Response Correlation approach in a non-Gaussian framework, improves the issue of overestimations of envelope values. Several envelopes of structural responses are considered: the mean of extremes and the 86% quantiles of extremes, together with two reference periods (10 min and 1 h). Extensive wind tunnel measurements have been collected, which correspond to 371 h full scale. This study is undertaken for quasi-static analysis of structures and is illustrated with a low-rise building. [less ▲]

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See detailMitigation of the torsional flutter phenomenon of bridge deck section during a lifting phase
Andrianne, Thomas ULiege; De Ville De Goyet, Vincent ULiege

in Mitigation of the torsional flutter phenomenon of bridge deck section during a lifting phase (2016, June)

This paper presents a complete analysis of the aeroelastic behaviour of a deck section during the construction stage of the Third Bosphorus Bridge in Istanbul, Turkey. The combination of the low torsional ... [more ▼]

This paper presents a complete analysis of the aeroelastic behaviour of a deck section during the construction stage of the Third Bosphorus Bridge in Istanbul, Turkey. The combination of the low torsional stiffness along the vertical axis and the unstable aerodynamic shape of the suspended deck section led to a torsional flutter instability for a low wind speed (9.6 m/s). This low critical wind speed was obviously very likely to occur on the site of construction, so that mitigation actions were be implemented. It was decided to cover partially the sides of the deck section in order to modify adequately its aerodynamic shape. It is demonstrated that the proposed aerodynamic counter-measures increase the critical torsional flutter wind speed up to 39.5 m/s (worst configuration), which is acceptable for the construction phase of the bridge. The proposed mitigation solution was implemented and no torsional oscillations were observed. [less ▲]

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See detailConditional expected static wind loads
Blaise, Nicolas ULiege; Andrianne, Thomas ULiege; Denoël, Vincent ULiege

in In Vento 2016 (2016)

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See detailAerodynamic benefit for a cyclist by a following motorcycle
Blocken, Bert; Toparlar, Yasin; Andrianne, Thomas ULiege

in Journal of Wind Engineering & Industrial Aerodynamics (2016)

In recent years, many accidents have occurred between cyclists and in-race motorcycles, even yielding fatal injuries. The accidents and the potential aerodynamics issues have impelled the present authors ... [more ▼]

In recent years, many accidents have occurred between cyclists and in-race motorcycles, even yielding fatal injuries. The accidents and the potential aerodynamics issues have impelled the present authors to perform dedicated wind-tunnel measurements and Computational Fluid Dynamics (CFD) simulations to assess cyclist drag reduction when followed by one, two or three motorcycles. The 3D steady-state Reynolds-Averaged Navier-Stokes simulations with the standard k-ε model are validated by the wind-tunnel tests. The cyclist drag reduction goes up to 8.7% for a single trailing motorcycle and to 13.9% for three trailing motorcycles at a distance of 0.25 m behind the cyclist. This distance is not uncommon in elite races, as evidenced by the many recent accidents. The effect by a single following motorcycle at realistic short distances d=0.25 m (8.7%), d = 0.5 m (6.4%) and d=1 m (3.8%) is larger than that by a following car at realistic short distance d=5 m (1.4%). Therefore it could be argued that in-race motorcycles are not only more dangerous but also aerodynamically more influential. This study reinforces the necessity for the International Cycling Union to change the rules concerning in-race motorcycles, not only to avoid accidents but also to avoid unwanted aerodynamic benefits. [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)

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See detailEmpirical modelling of the bifurcation behaviour of a bridge deck undergoing across-wind galloping
Andrianne, Thomas ULiege; Dimitriadis, Grigorios ULiege

in Journal of Wind Engineering & Industrial Aerodynamics (2014), 135

This work presents an empirical model capable to describe the galloping bifurcation behaviour of a bridge deck. It is based on a general polynomial form proposed by Novak, which we limit to the 5th order ... [more ▼]

This work presents an empirical model capable to describe the galloping bifurcation behaviour of a bridge deck. It is based on a general polynomial form proposed by Novak, which we limit to the 5th order. The advantage of choosing this function for modelling the vertical force coefficient is that asymmetry of the even terms is enforced in order to reproduce the sub-critical aeroelastic behaviour of the bridge deck. The coefficients of the polynomial are identified from several pairs of displacement amplitudes and the corresponding airspeeds, measured in a wind tunnel during dynamic tests on the sectional bridge model. The identification is carried out using a first order harmonic balance technique. A stability analysis is presented in order to highlight the need of such a model to catch the complete bifurcation behaviour of the system. The resulting force coefficient of this full order model is compared to the well known models of Parkinson and Novak. Finally, the concept universal curve is used in order to discuss the galloping responses of square and rectangular cylinders, in comparison with the one of the bridge deck. [less ▲]

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See detailWind Tunnel Testing of a VTOL MAV Propeller in Tilted Operating Mode
Theys, Bart; Dimitriadis, Grigorios ULiege; Andrianne, Thomas ULiege et al

in Proceedings of the 2014 International Conference on Unmanned Aircraft Systems (ICUAS 2014) (2014, May 30)

This paper presents experimental results of the full 3-axis force vector and 3-axis moment vector acting on a propeller, commonly used for a Vertical Take Off and Landing Micro Aerial Vehicle (VTOL MAV ... [more ▼]

This paper presents experimental results of the full 3-axis force vector and 3-axis moment vector acting on a propeller, commonly used for a Vertical Take Off and Landing Micro Aerial Vehicle (VTOL MAV). Measurements were carried out in a wind tunnel using a high resolution 6-axis force/moment sensor embedded in a customized test rig at several wind speeds, propeller rotational speeds and angles of the propeller shaft with respect to the air stream. Results show strong moments acting on the propeller in forward flight and unstable conditions in descending flight. Power calculations reveal a decrease in power consumption during slow forward flight and how motor efficiency can be maximized. [less ▲]

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