Finite Volume vs.vs. Streaming-based Lattice Boltzmann algorithm for fluid-dynamics simulations: a one-to-one accuracy and performance study

A new finite volume (FV) discretisation method for the Lattice Boltzmann (LB) equation which combines high accuracy with limited computational cost is presented. In order to assess the performance of the FV method we carry out a systematic comparison, focused on accuracy and computational performances, with the standard $streaming$ (ST) Lattice Boltzmann equation algorithm. To our knowledge such a systematic comparison has never been previously reported. In particular we aim at clarifying whether and in which conditions the proposed algorithm, and more generally any FV algorithm, can be taken as the method of choice in fluid-dynamics LB simulations. For this reason the comparative analysis is further extended to the case of realistic flows, in particular thermally driven flows in turbulent conditions. We report the first successful simulation of high-Rayleigh number convective flow performed by a Lattice Boltzmann FV based algorithm with wall grid refinement.Comment: 15 pages, 14 figures (discussion changes, improved figure readability

Particle-laden two-dimensional elastic turbulence

The aggregation properties of heavy inertial particles in the elastic turbulence regime of an Oldroyd-B fluid with periodic Kolmogorov mean flow are investigated by means of extensive numerical simulations in two dimensions. Both the small and large scale features of the resulting inhomogeneous particle distribution are examined, focusing on their connection with the properties of the advecting viscoelastic flow. We find that particles preferentially accumulate on thin highly elastic propagating waves and that this effect is largest for intermediate values of particle inertia. We provide a quantitative characterization of this phenomenon that allows to relate it to the accumulation of particles in filamentary highly strained flow regions producing clusters of correlation dimension close to 1. At larger scales, particles are found to undergo turbophoretic-like segregation. Indeed, our results indicate a close relationship between the profiles of particle density and fluid velocity fluctuations. The large-scale inhomogeneity of the particle distribution is interpreted in the framework of a model derived in the limit of small, but finite, particle inertia. The qualitative characteristics of different observables are, to a good extent, independent of the flow elasticity. When increased, the latter is found, however, to slightly reduce the globally averaged degree of turbophoretic unmixing.Comment: 12 pages, 9 figures. Submitted to EPJ

Estuary English: Revisiting the Debate on its Status as a New Accent of English and Potential EFL Pronunciation Model

This paper examines the ontological status of the supposedly new accent of England termed Estuary English by comparing its phonetics with those of Received pronunciation and Cockney, two varieties with which Estuary English is often compared. The paper also discusses some of the criteria that may be used to draw the boundaries between the three varieties and the potential status of Estuary English as a pronunciation model in the field of English language teaching

Dispositivos Analógicos Programables

Introducción a los dispositivos programables anal ógicos. Dispositivos TRAC, ispPAC y Anadigm: arquitectura,interconexiones, macros, fases de diseño, software de diseño, etc. Aplicacione

Architectures of Emergency. Sentinel operations for a rapidly changing environment

[EN] The declaration of an emergency is given by various protocols that respond to a series of interventions driven by an environmental urgency (Anderson 2017), designed by global networks of experts that mobilize advertising modes of economic development in the face of environmental collapse (Goh 2021). This research proposes a different imaginary of the Emergency. This reflection aims to resignify the Emergency from the embodied experiences of the disruptive events we live, opening the discussion on the frictions between a normative world based on human security and the modalities of militant movements dedicated to redressing social, environmental, and economic inequalities (Whyte 2018). In this sense, we develop the idea of sentinel modes of care that reflect the affective scaffolding of life-related to the environment and potential catastrophe (Wright, Plahe, and Jack 2022). A state of constant alertness characterizes sentinel care within a more-than-human register of the relationship and potentialities of the territory. This text aims to position itself on emergency protocols while exploring other imaginaries and their impact on spatial practices.Mompean Botias, E. (2023). Architectures of Emergency. Sentinel operations for a rapidly changing environment. Editorial Universitat Politècnica de València. 598-611. https://doi.org/10.4995/VIBRArch2022.2022.1527459861

Biblioteca central i estatal a la presó Model de Barcelona

La presó Model de Barcelona fou projectada pels arquitectes Salvador Vinyals i Domènech i Estepà a causa de la reforma penitenciària a finals del segle XIX. L’ojectiu principal d’aquesta reforma era privar el reu de qualsevol contacte perniciós, d’aquí el naixement de la presó cel·lular. La finalització de la seva construcció data del 1904. La presó Model, tal i com el seu nom indica, es el “model” a seguir. La seva morfologia panòptica, derivada del principi de l’utilitarisme d’en Jeremy Bentham, permet la centralització del poder en el volum central i, per tant, el control total del reu amb menor quantitat de personal funcionari. El programa actual se subdivideix en tres grans grups: L’administratiu, el de serveis i el panòptic. Els tres programes es desenvolupen concèntricament creant un gradient de llibertat. La presó Model se situa longitudinalment entre els carrers Roselló i Provença amb una diferència de nivell de 3,2m. El nivell principal del conjunt se situa en cota intermedia entre els dos nivells. El programa administratiu se situa en tot el perímetre, seguidament es desenvolupa la corona de serveis i per últim i com a element central se situa el panòptic, element sense llibertat. El projecte es compon de tres franges programàtiques concèntriques: una exterior, on se situa la zona d'acollida i promoció i la zona infantil, una intermèdia, que serveix la primera permetent que sigui totalment diàfana i l'edifici panòptic central. A la planta primera es desenvolupa el parc interior d'illa vinculat a l'edifici panòptic i connectat visualment amb els carrers dels voltants i amb les zones d'acollida i promoció infantil. Pel que fa a l'edifici panòptic, es proposa un esponjament de la seva superfície preservant les característiques principals de l'edificació. La nau central es conserva mentre que, de les naus laterals, s'enderroquen d'alguns dels murs els forjats que configuren les cel·les, creant un joc de visuals entre les zones dels diferents nivells

Nuevas aportaciones al estudio de dos estelas decoradas halladas en la cuenca sur del Duero (Beira Alta, Portugal)

En el presente trabajo hemos realizado el estudio de dos nuevas estelas decoradas del tipo II de Almagro Basch que fueron halladas en la región de Beira Alta (Portugal), y cuya valoración nos ha permitido extraer nuevas e interesantes aportaciones al confuso panorama que rodea esta manifestación cultural que caracteriza parte del bronce final peninsular

Institutionnalisation et dissémination d'une innovation à l'université

National audienceTaking the example of a multimedia learning environment (Virtual Cabinet) originally designed for the learning of English, this article explores the way a local innovation developed in a contextualised research-and-development framework can turn into an institutional learning environment adapted to other universities. Two aspects related to innovation will be particularly developed : the necessity to respect certain norms in order to permit its exportation to other contexts and the need to follow a certain number of phases that allow its normalisation. The results of a longitudinal study among users are indicators of the on-going normalisation process of the learning environment and of its appropriation by the different actors. Finally, the study of the “resemiotisation” process undergone by the original scenario when adapted to different languages by the new partners and the analysis of the dissemination process and the subsequent network created around it will be carried on taking into account semiotic and symbolic appropriation.En prenant l'exemple d'un site d'apprentissage médiatisé destiné à l'apprentissage de l'anglais (Virtual Cabinet), la présente contribution vise à montrer comment une innovation locale, développée dans le cadre d'une recherche-développement contextualisée, peut devenir un dispositif institutionnel utilisable dans d'autres universités. Deux aspects liés à l'innovation seront particulièrement explicités, à savoir le respect en amont de diverses normes qui facilitent son exportation vers d'autres contextes et le passage par un certain nombre de phases qui assurent sa normalisation. Les résultats d'une enquête longitudinale auprès des utilisateurs cibles fournissent des indications quant à la normalisation du dispositif et à son appropriation par les acteurs. Enfin, en étudiant de quelle façon les partenaires ont "resémiotisé" le scénario original pour l'adapter à une langue différente, les aspects liés à la dissémination et au travail en réseau sont analysés sur les axes de l'appropriation sémiotique et symbolique

An objective perspective for classic flow classification criteria

Four classic criteria used to the classification of complex flows are discussed here. These criteria are useful to identify regions of the flow related to shear, elongation or rigid-body motion. These usual criteria, namely $Q$, $\Delta$, $\lambda_{2}$ and $\lambda_{cr}/\lambda_{ci}$, use the fluid's rate-of-rotation tensor, which is known to vary with respect to a reference frame. The advantages of using objective (invariant with respect to a general transformation on the reference frame) criteria are discussed in the present work. In this connection, we construct versions of classic criteria replacing standard vorticity, a non-objective quantity, by effective vorticity, a rate of rotation tensor with respect to the angular velocity of the eigenvectors of the strain rate tensor. The classic criteria and their corresponding objective versions are applied to classify two complex flows: the transient ABC flow and the flow through the abrupt 4:1 contraction. It is shown that the objective versions of the criteria provide richer information on the kinematics of the flowComment: 11 pages, 4 figures (minor corrections and improvements