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Peer Reviewed
See detailNumerical and experimental evaluation of lateral torsional buckling of beams at elevated temperatures
Piloto, Paulo; Vila Real, Paulo; Franssen, Jean-Marc ULg

in Proc. Computational Meth. and Experimental Measurements (2001)

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See detailNumerical and experimental investigation of fiber drawing process
Chouffart, Quentin ULg; Simon, Philippe; Terrapon, Vincent ULg

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 detailNumerical and Experimental Investigation of Slot-Blowing Air Over a Cylinder
Runge, William; Buysschaert, Frank; Hayez, Jules et al

in Proceedings of the 5th European Conference for Aeronautics and Space Sciences (2013, July)

Tangential slot blowing around a cylinder in the Coanda effect has been proposed as a mechanism for yaw control in a novel coaxial helicopter. The proposed design has been investigated computationally ... [more ▼]

Tangential slot blowing around a cylinder in the Coanda effect has been proposed as a mechanism for yaw control in a novel coaxial helicopter. The proposed design has been investigated computationally, using the unsteady k-ω SST solver in NUMECA, as well as experimentally in the wind tunnel at the Université de Liège. While the concept in general is promising, it has been shown that there are some potential problems, including pitch-yaw coupling and some unsteady flow conditions. These problems exist under varied circumstances, and, exist at least in part due to the complicated flow-field in this problem, even in 2-dimensions. [less ▲]

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See detailNumerical and Experimental Investigations of Simple 2-D Geometries in Slamming
Constantinescu, A.; El Malki Alaoui, A.; Neme, A. et al

in IMDC’2009, 10th Inter Marine Design Conference, 26-29 May 2009, Trondheim, Norway (2009, May)

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See detailNumerical and experimental research in river hydrodynamics and hydraulic engineering
Dewals, Benjamin ULg

Conference (2006, September 29)

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See detailNumerical and Experimental Studies of Simple Geometries in Slamming
Constantinescu, A.; Aboulghit, El Malki Aloui; Nême, Alain et al

in International Journal of Offshore and Polar engineering (2011, September)

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See detailNumerical and nonnumerical estimation in children with and without mathematical learning disabilities
Mejias Vanslype, Sandrine ULg; Mussolin, Christophe; Rousselle, Laurence ULg et al

in Child Neuropsychology (2011), 18(6), 550-575

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See detailNumerical and physical hydraulic modelling of Piano Key Weirs
Erpicum, Sébastien ULg; Machiels, Olivier ULg; Dewals, Benjamin ULg et al

in Proceedings of the 4th Int. Conf. on Water Resources and Renewable Energy Development in Asia (2012, March)

During the last few years, several piano key weirs (PKWs) have been built in France by Electricité de France (EDF). Thanks to the reduced footprint and high release capacities of this new type of weir ... [more ▼]

During the last few years, several piano key weirs (PKWs) have been built in France by Electricité de France (EDF). Thanks to the reduced footprint and high release capacities of this new type of weir, making it particularly suited for concrete dams rehabilitation, lots of other projects in varied countries are under construction or study. The prototype use of PKW requires knowledge about its structural behaviour, hydraulic capacities as well as integration into dams’ environment. This paper aims at presenting numerical and physical modelling works performed at the University of Liege to address the last two points. In particular, large scale physical modelling and parametric scale models enabled to understand the hydraulic behaviour of the structure and to highlight its main geometric parameters as well as their best variation interval depending on various criteria related to the weir design (discharge efficiency, cost…). A 1D numerical model has also been developed based on these experimental investigations. It enables to predict in a few minutes, with 10% accuracy, the discharge capacity of a given PKW geometry on its usual operation head range. This model, available as a freeware on http://www.pk-weirs.ulg.ac.be, constitutes a key tool for the first design of such weirs. Finally, the scale model studies of major projects such as Raviège dam (France) for EDF and Ouldjet Mellegue Project (Algeria) for Coyne et Bellier – Tractebel Engineering enable to confront theoretical predictions with experimental results and to address the problem of PKW integration on dam crests. [less ▲]

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See detailNumerical applications to radiative transfer in expanding envelopes - The two-level atom model
Surdej, Jean ULg

in Astronomy and Astrophysics (1978), 66

The escape probability method developed by Sobolev (1947) is applied to the case of a two-level atom. The numerical applications are based on a previous work concerning a general theory of spectral-line ... [more ▼]

The escape probability method developed by Sobolev (1947) is applied to the case of a two-level atom. The numerical applications are based on a previous work concerning a general theory of spectral-line formation in outward-accelerating and outward-decelerating stellar envelopes. Only the radiative exchanges occurring between the atomic levels are considered, and the statistical-equilibrium equations are solved rigorously in the cases of a transparent medium at rest, an outward-accelerating envelope, and an outward-decelerating envelope. The population of the atomic levels are compared for different physical conditions in each case. It is shown numerically that in the case of an outward-decelerating envelope the contribution of distant atoms to the mean intensity of line radiation appreciably enhances the degree of excitation throughout the envelope. [less ▲]

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See detailNumerical approach of contact using an augmented lagrangian method
Bille, J.Ph.; Habraken, Anne ULg; Charlier, Robert ULg

in Congrès National Belge de Mécanique Théorique et Appliquée (1994)

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See detailNumerical approach of contact using an augmented lagrangian method
Bille, J.Ph.; Cescotto, Serge ULg; Habraken, Anne ULg et al

in 2nd Contact Mechanics Int. Symp., CMIS (1994, September)

Detailed reference viewed: 12 (6 ULg)
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See detailNumerical approach of contact with friction between two bodies in large deformations
Habraken, Anne ULg; Radu, Jean-Pol ULg; Charlier, Robert ULg

in Proc. of the Contact Mechanics Int. Symp. (1992, October)

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See detailNumerical assessment of concrete damage: procedures and pitfalls
Stroeven, Piet; He, Huan ULg

in Heron (2011), 56(3), 123-140

The paper focuses on the quality of predicting the damage characteristics of the loaded engineering structure by subjecting section images of cores supposedly drawn from the concrete of the structure to ... [more ▼]

The paper focuses on the quality of predicting the damage characteristics of the loaded engineering structure by subjecting section images of cores supposedly drawn from the concrete of the structure to quantitative image analysis by sweeping test lines. Automation of this data acquisition stage is shown, generally leading to information that is biased to an unknown degree. This is accomplished mathematically and graphically according to Underwood. When the Stroeven/Saltikov (S/S)-concept of a partially linear-planar model for damage is accepted and (four-connexity) digitization is accomplished in a direction adjusted to the prevailing orientation direction of the cracks, the paper shows that orthogonal observations in vertical sections are sufficient for the unbiased assessment of total crack length per unit of area (2D), or specific crack surface area (3D), also when digitized images are employed. This is possible in situations where (uniaxial) compressive or tensile stresses dominate. The crack orientation distribution is however always biased when determined on digitized images in an automated set up when pixel directions are not compensated for, such as by the quantified S/S-concept of damage. [less ▲]

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See detailA numerical comparison of control strategies applied to an existing ice storage system
Lemort, Vincent ULg

in Energy Conversion and Management (2006), 47(20), 3619-3631

While ice storage systems are designed according to a defined strategy for warm day loads, it is interesting to consider other conventional control strategies for mid-season day loads. Three different ... [more ▼]

While ice storage systems are designed according to a defined strategy for warm day loads, it is interesting to consider other conventional control strategies for mid-season day loads. Three different charging-discharging control strategies are applied to an existing cooling plant and compared in terms of operating costs and energy consumption. A cooling plant model is built. A time stage equal to 15 min is considered to simulate numerically a whole charging-discharging process and compare the different control strategies. These simulations take into account existing technical constraints and set points. EES software is used. The operating costs of the cooling plant are evaluated by taking into account both the energy and the demand cost rate. It is shown that an ice storage system can allow savings of operating costs. However, they can increase energy consumption. (c) 2006 Elsevier Ltd. All rights reserved. [less ▲]

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See detailNumerical computation of nonlinear normal modes of nonconservative systems
Renson, Ludovic ULg; Kerschen, Gaëtan ULg

in Proceedings of the ASME IDETC/CIE 2013 (2013, August)

Since linear modal analysis fails in the presence of nonlinear dynamical phenomena, the concept of nonlinear normal modes (NNMs) was introduced with the aim of providing a rigorous generalization of ... [more ▼]

Since linear modal analysis fails in the presence of nonlinear dynamical phenomena, the concept of nonlinear normal modes (NNMs) was introduced with the aim of providing a rigorous generalization of linear normal modes to nonlinear systems. Initially defined as periodic solutions, numerical techniques such as the continuation of periodic solutions were used to compute NNMs. Because these methods are limited to conservative systems, the present study targets the computation of NNMs for nonconservative systems. Their definition as invariant manifolds in phase space is considered. Specifically, the partial differential equations governing the manifold geometry are considered as transport equations and an adequate finite element technique is proposed to solve them. The method is first demonstrated on a conservative nonlinear beam and the results are compared to standard continuation techniques. Then, linear damping is introduced in the system and the applicability of the method is demonstrated. [less ▲]

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See detailNumerical computation of one-photon mazer resonances for arbitrary field modes
Bastin, Thierry ULg; Solano, E.

in Computer Physics Communications (2000), 124

We present a novel approach for solving numerically one-dimensional scattering problems and apply it for computing the emission probability of an ultracold atom interacting with an arbitrary field mode of ... [more ▼]

We present a novel approach for solving numerically one-dimensional scattering problems and apply it for computing the emission probability of an ultracold atom interacting with an arbitrary field mode of a high-Q cavity. Our method is efficient, stable and succeeds when other numerical integration methods fail. It also replaces and improves advantageously the WKB approximation. The cases of sinusoidal, sech2 and Gaussian field modes are studied and compared. Divergences with previous works, where WKB was used, are found. [less ▲]

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See detailNumerical computation of the electrostatic interaction energy between methanol and the dyad water-imidazole
Dehareng, Dominique ULg; Dive, Georges ULg; Lamotte-Brasseur, Josette ULg et al

in Theoretica Chimica Acta (1989), 76(2), 85-94

The electrostatic interaction energy between methanol and the dyad water-imidazole has been computed numerically at three levels of approximation from 3D grids of the charge density of one partner and the ... [more ▼]

The electrostatic interaction energy between methanol and the dyad water-imidazole has been computed numerically at three levels of approximation from 3D grids of the charge density of one partner and the electrostatic potential of the other. The minimum positions and energy values thus obtained compare well with those calculated analytically. The numerical procedure is especially interesting for the prediction of the stable conformers. [less ▲]

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See detailNumerical computations of hypersonic boundary layer roughness induced transition on a at plate
Serino, Gennaro ULg; Pinna, Fabio; Rambaud, Patrick et al

Scientific conference (2012, January)

The work is focused on numerical simulations of roughness induced transition for hypersonic ow on a at plate wall mounted roughness element. Numerical simulations are compared to experimental results in ... [more ▼]

The work is focused on numerical simulations of roughness induced transition for hypersonic ow on a at plate wall mounted roughness element. Numerical simulations are compared to experimental results in order to resemble the physics highlighted in the tests. In particular, stress has been placed on the detection of the vortices in the wake behind the roughness element and on the onset of transition. [less ▲]

Detailed reference viewed: 64 (7 ULg)