Why and How 'To Do Science'? On the Often Ambiguous Relationship between Architecture and the Social Sciences in France in the Wake of May '68

Around the time of the ‘events’ of May ’68, ‘architectural research’ in France posited itself as a direct challenge to the education of the ‘Beaux-Arts’, to the school’s insulation from academic disciplines and to its common lack of a critical dimension required by any ‘scientific’ approach. In this context, the sociologists’ contribution to architecture was long awaited but soon proved to be disappointing, undoubtedly disappointing because the expectations were unreasonably high. In the early 1970s, the contributions of sociologists were perceived as a way to respond to doubts about the professional status of the architect; increasingly, sociologists discerned a desire to escape from the responsibilities and risks of the architectural project, into the sociological discourse. At the same time, following numerous disappointments, even the formerly zealous partisans of the arrival of sociologists finally returned to more skeptical positions towards the role of sociologists in architectural education. This uneasiness is marked by the silence, not to say the omerta, that veils today in France the adhesion of a number of architects of that generation to an ‘architectural postmodernism’ as it was defined during the 1970s, a moment embodied by the contribution of sociologists to the recent history of architecture. Nevertheless, it is the inheritance that makes the heir, as Pierre Bourdieu used to say

On the maximum time step in weakly compressible SPH

International audienceIn the SPH method for viscous fluids, the time step is subject to empirical stability criteria. We proceed to a stability analysis of the Weakly Compressible SPH equations using the von Neumann approach in arbitrary space dimension for unbounded flow. Considering the continuous SPH interpolant based on integrals, we obtain a theoretical stability criterion for the time step, depending on the kernel standard deviation, the speed of sound and the viscosity. The stability domain appears to be almost independent of the kernel choice for a given space discretisation. Numerical tests show that the theory is very accurate, despite the approximations made. We then extend the theory in order to study the influence of the method used to compute the density, of the gradient and divergence SPH operators, of background pressure, of the model used for viscous forces and of a constant velocity gradient. The influence of time integration scheme is also studied, and proved to be prominent. All of the above theoretical developments give excellent agreement against numerical results. It is found that velocity gradients almost do not affect stability, provided some background pressure is used. Finally, the case of bounded flows is briefly addressed from numerical tests in three cases: a laminar Poiseuille flow in a pipe, a lid-driven cavity and the collapse of a water column on a wedge

Micromodel-based simulations for laminated composites

International audienceWe develop a calculation strategy for the simulation of a complete microscopic model. This strategy enables one to account for damage mechanisms in laminated composites. The model mixes discrete and continuous approaches by introducing potential rupture surfaces and a damageable continuous medium. This approach requires suitable calculation tools unavailable in industrial analysis codes. The strategy presented is multiscale in space and is based on a decomposition of the domain into substructures and interfaces. This strategy enables one to simulate complex problems with multiple cracks. In practice, to use such a model, the strategy must be improved in order to handle very large numbers of substructures and interfaces and to estimate the rupture criteria for the surfaces introduced into the model. We provide simple examples which demonstrate the capabilities of the microscopic model

Eco-neighbourhoods: the last frustrated outline of the great history of Utopia?

[EN] Utopia today draws a critical horizon rather than a promising future. Too often, this promise may have been a tool to plea for patience and justify the immediate sacrifices in the name of a nebulous future. For a long time the construction of the city was an integral part of a larger project to build a new society. But under the contemporary aegis of "sustainable development", the new sentence is yet to take an original form. In eco-neighbourhoods, the plot is still despotic, and it only re-emerges from its box under the spectre of heliotropism, under the aegis of thermal performance and of neighbourhood plans dictated by the housing orientation. As for the "smart city" -a discovery of the field of marketing-, it will always draw a smile in our faces. Whereas sustainable development emerged in the 2000s as a soft and unanimous slogan, degrowth took over in the 2010s, turning into a hard cleaving slogan. But how to envision the "project" within this horizon without adopting a regressive posture?[FR] L’utopie aujourd’hui dessinerait un horizon critique plutôt que des «lendemains qui chantent»: ces derniers n’auront trop souvent été qu’une arme de patience justifiant les sacrifices immédiats au nom d’un futur nébuleux. Longtemps la construction de la ville a pourtant fait partie intégrante d’un projet plus vaste d’édification d’une société nouvelle. Mais sous l’égide contemporaine du «développement durable», le nouveau peine encore à prendre une forme originale. Dans les écoquartiers, le parcellaire est toujours aussi despotique, et il n’est pas jusqu’au spectre de l’héliotropisme qui ne surgisse à nouveau de sa boîte sous l’égide de la performance thermique et des plans de quartier dictés par l’orientation des logements. Quant à la «ville intelligente», encore une trouvaille du marketing, cette smart city nous fera toujours sourire un peu, que voulez-vous, créative et durable! Là où le développement durable a émergé au fil des années 2000 comme un slogan mou et unanimiste, c’est plutôt la décroissance qui l’a supplanté au fil des années 2010 comme un slogan cette fois-ci dur et clivant. Mais comment donc penser le «projet» à l’aune de cet horizon sans adopter une posture régressive ?Violeau, J. (2018). Eco-neighbourhoods: the last frustrated outline of the great history of Utopia?. VLC arquitectura. Research Journal. 5(2):1-28. doi:10.4995/vlc.2018.10619SWORD12852Abensour, Miguel. Entretien avec Sonia Dayan-Herzbrun, Anne Kupiec et Numa Murard. «L'homme est un animal utopique». Mouvements, n°45-46 dossier «Le nouvel esprit utopique» (mai-août 2006): 83.Ariès, Paul et al. Non au capitalisme vert. Lyon: Parangon/Vs, 2009.Benoist, Alain de. Décroissance ou toujours plus?: penser l'écologie jusqu'au bout. Paris: Pierre-Guillaume de Roux, 2018.Charmes, Eric. La ville émiettée. Paris: PUF, 2011. https://doi.org/10.3917/puf.catal.2011.01Druot, Frédéric, Anne Lacaton et Jean-Philippe Vassal. Plus: la vivienda colectiva, territorio de excepción = les grands ensembles de logement, territoire d'exception = large-scale housing developments, an exceptional case. Barcelona: Gustavo Gili, 2007.Gorz, André. Écologie et Politique. Paris: Seuil coll. «Points Politique», 1978. Ed. orig.: Paris: Galilée, 1975.Guattari, Félix. les Trois Écologies. Paris: Galilée, 1989.Mantziaras, Panos. La Ville-Paysage. Rudolf Schwarz et la dissolution des villes. Genève: MetisPresses, 2008.Secchi, Bernardo. La ville du vingtième siècle. Paris: Recherches éd., 2009. Ed. orig.: Bari: Laterza, 2005

An overview on the capabilities of the TELEMACMASCARET system to deal with tsunamis: feedbacks from TANDEM project

Water Qualit

Unified semi-analytical wall boundary conditions applied to 2-D incompressible SPH

International audienceThis work aims at improving the 2-D incompressible SPH model (ISPH) by adapting it to the unified semi-analytical wall boundary conditions proposed by Ferrand et al. [10]. The ISPH algorithm considered is as proposed by Lind et al. [25], based on the projection method with a divergence-free velocity field and using a stabilising procedure based on particle shifting. However, we consider an extension of this model to Reynolds-Averaged Navier-Stokes equations based on the k- turbulent closure model, as done in [10]. The discrete SPH operators are modified by the new description of the wall boundary conditions. In particular, a boundary term appears in the Laplacian operator, which makes it possible to accurately impose a von Neumann pressure wall boundary condition that corresponds to impermeability. The shifting and free-surface detection algorithms have also been adapted to the new boundary conditions. Moreover, a new way to compute the wall renormalisation factor in the frame of the unified semi-analytical boundary conditions is proposed in order to decrease the computational time. We present several verifications to the present approach, including a lid-driven cavity, a water column collapsing on a wedge and a periodic schematic fish-pass. Our results are compared to Finite Volumes methods, using Volume of Fluids in the case of free-surface flows. We briefly investigate the convergence of the method and prove its ability to model complex free-surface and turbulent flows. The results are generally improved when compared to a weakly compressible SPH model with the same boundary conditions, especially in terms of pressure prediction

Diffusion in grid turbulence of isotropic macro-particles using a Lagrangian stochastic method: theory and validation.

The prediction of solid bodies transport (such as algae, debris, sediment grains, or corrosion deposits) is a necessary requirement in many industrial or environmental processes. The physical processes involved cover a wide range of processes, from tidal flow to turbulent eddies and particle drag. A stochastic model was therefore developed to link the different scales of the physical processes where it was assumed that the particles are dilute enough that they do not affect the flow or the motion of other particles while being large enough that each particle does not follow exactly the fluid motions (i.e., macro-particles). The stochastic model is built in such a way that it uses Reynolds-averaged fluid properties to predict trajectories of individual particles. This model was then tested using experimental measurements obtained for isotropic particles released in semi-homogeneous turbulence. The turbulent flow was generated using a pair of oscillating grids and was characterized using particle image velocimetry measurements. The trajectories of the particles were measured using a pair of high resolution cameras. The comparison between the experimental data and different numerical models gives satisfactory results