Now showing items 1-20 of 107

  • Algoritmos de punto de cambio aplicados a la detección de estructuras vorticosas en flujos turbulentos 

    Marañón Di Leo, J.; Calandra, M.V.; Delnero, J.S. (Universitat Politècnica de Catalunya. CIMNE, 2017)
    Article
    Open Access
    En este trabajo se presenta el análisis de la aplicación del modelo de un algoritmo de punto de cambio (Change Point Model, CPM), basado en tests no paramétricos, para la detección de estructuras turbulentas en un flujo ...
  • A measure of flow vorticity with twisted beams of light 

    Belmonte Molina, Aniceto; Rosales Guzmán, Carmelo; Pérez Torres, Juan (Curran, 2016)
    Conference report
    Restricted access - publisher's policy
    The measurement of vorticity, a parameter providing local measurements of rotation at every point in a flow, would greatly assist research fields as diverse as biology microfluidics, complex motions in the oceanic and ...
  • Análisis multifractal de procesos autosimilares : imágenes de satélite e inestabilidades baroclinas 

    Redondo Apraiz, José Manuel; Busquets Grau, Joan; Platónov, Alexéi Konstantínovich; Garzón Bedoya, Germán (2008-05-05)
    Article
    Open Access
  • Analysis of sedimentation and resuspension processes of aquaculture biosolids using an oscillating grid 

    Masaló Llorà, Ingrid; Guadayol, Oscar; Peters, Francesc; Oca Baradad, Joan (2008-01)
    Article
    Restricted access - publisher's policy
    Sedimentation and resuspension processes of aquaculture biosolids (non-ingested feed and faeces) are analysed using vertically oscillating grids as a source of turbulence in fluid tanks. An oscillating grid system consists ...
  • Analysis of turbulence in fog episodes 

    Terradellas, Enric; Ferreres Soler, Enriqueta; Soler, M. R. (Copernicus Publications, 2008-04-24)
    Article / Conference report
    Open Access
    Many processes interact in a complex and highly non-linear way during the life cycle of fog, the turbulent transport being among them. Observations and analysis of urbulence are, then, fundamental to our understanding of ...
  • A new subgrid characteristic length for turbulence simulations on anisotropic grids 

    Trias Miquel, Francesc Xavier; Gorobets, Andrei; Silvis, Maurits; Verstappen, Roel; Oliva Llena, Asensio (2017-11-29)
    Article
    Open Access
    Direct numerical simulations of the incompressible Navier-Stokes equations are not feasible yet for most practical turbulent flows. Therefore, dynamically less complex mathematical formulations are necessary for coarse-grained ...
  • A numerical strategy to compute optical parameters in turbulent flow: application to telescopes 

    Codina, Ramon; Baiges Aznar, Joan; Pérez Sánchez, Daniel; Collados, Manuel (2008-07-29)
    Article
    Open Access
    We present a numerical formulation to compute optical parameters in a turbulent air flow. The basic numerical formulation is a large eddy simulation (LES) of the incompressible Navier-Stokes equations, which are approximated ...
  • A priori study of subgrid-scale features in turbulent Rayleigh-Bénard convection 

    Dabbagh, Firas; Trias Miquel, Francesc Xavier; Gorobets, Andrei; Oliva Llena, Asensio (2017-10-06)
    Article
    Open Access
    At the crossroad between flow topology analysis and turbulence modeling, a priori studies are a reliable tool to understand the underlying physics of the subgrid-scale (SGS) motions in turbulent flows. In this paper, ...
  • A simple approach to discretize the viscous term with spatially varying (eddy-)viscosity 

    Trias Miquel, Francesc Xavier; Gorobets, Andrei; Oliva Llena, Asensio (2013-11-15)
    Article
    Restricted access - publisher's policy
    A simple approach to discretize the viscous dissipation term in the incompressible Navier–Stokes equations with spatially varying viscosity is presented. Unlike the case where the viscosity remains constant, its discretization ...
  • Assessment of variational multiscale models for the large eddy simulation of turbulent incompressible flows 

    Colomés Gené, Oriol; Badia, Santiago; Codina, Ramon; Principe, Ricardo Javier (2015-03)
    Article
    Open Access
    In this work we study the performance of some variational multiscale models (VMS) in the large eddy simulation (LES) of turbulent flows. We consider VMS models obtained by different subgrid scale approximations which include ...
  • Atmospheric-turbulence-induced power-fade statistics for a multiaperture optical receiver 

    Belmonte Molina, Aniceto; Comerón Tejero, Adolfo; Rubio, Juan Antonio; Fernández (OPTICAL SOC AMER, 1997-01-31)
    Article
    Open Access
    To estimate the probability distributions of power fades, we consider two basic types of disturbance in electromagnetic wave propagation through atmospheric turbulence: wave-front intensity fluctuations and wave-front ...
  • Blending regularization and large-eddy simulation. From homogeneous isotropic turbulence to wind farm boundary layers 

    Folch Flórez, David; Trias Miquel, Francesc Xavier; Gorobets, Andrei; Oliva Llena, Asensio (2013)
    Conference lecture
    Restricted access - publisher's policy
    The incompressible Navier-Stokes equations form an excellent mathematical model for turbulent flows. However, direct simulations at high Reynolds numbers are not feasible because the convective term produces far too many ...
  • Bubble dynamics in turbulent duct flows: Lattice-Boltzmann simulations and drop tower experiments 

    Bitlloch, Pau; Ruiz Martí, Xavier; Ramírez de la Piscina Millán, Laureano; Casademunt Viader, Jaume (2018-06-23)
    Article
    Open Access
    Lattice-Boltzmann simulations of a turbulent duct flow have been carried out to obtain trajectories of passive tracers in the conditions of a series of microgravity experiments of turbulent bubble suspensions. The statistics ...
  • Building a proper tensor-diffusivity model for large-eddy simulation of buoyancy-driven flows 

    Trias Miquel, Francesc Xavier; Dabbagh, Firas; Gorobets, Andrei; Oliva Llena, Asensio (International Centre for Numerical Methods in Engineering (CIMNE), 2018)
    Conference report
    Restricted access - publisher's policy
    In this work, we plan to shed light on the following research question: can we ¿nd a nonlinear tensorial subgrid-scale (SGS) heat ¿ux model with good physical and numerical properties, such that we can obtain satisfactory ...
  • Building proper invariants for eddy-viscosity subgrid-scale models 

    Trias Miquel, Francesc Xavier; Folch, David; Gorobets, Andrei; Oliva Llena, Asensio (2015-06-23)
    Article
    Open Access
    Direct simulations of the incompressible Navier-Stokes equations are limited to relatively low-Reynolds numbers. Hence, dynamically less complex mathematical formulations are necessary for coarse-grain simulations. ...
  • Chaotic advection, transport and patchiness in clouds of pollution in an estuarine flow 

    Stirling, James Robert (American Institute of Mathematical Sciences, 2001)
    Article
    Open Access
    We present an application of the transport theory developed for area preserving dynamical systems, to the problem of pollution and in particular patchiness in clouds of pollution in partially stratified estuaries. We ...
  • Coherent structures and feedback control of wall turbulence 

    Vicenza, Fabio (Universitat Politècnica de Catalunya, 2010-09)
    Master thesis (pre-Bologna period)
    Restricted access - author's decision
    Turbulencia y fenómenos concomitantes como transferencia de calor, difusión, resistencia de fricción y ruido juegan un papel importante en los problemas industriales y ambientales. Desde el punto de vista de ahorro de ...
  • Cold-air pool evolution in a wide Pyrenean valley 

    Conangla Triviño, Laura; Cuxart Rodamillans, Joan; Jiménez Cortés, M. Antònia; Martínez Villagrasa, Daniel; Miró Cubells, Josep Ramon; Tabarelli, Davidde; Zardi, Dino (Wiley, 2018-03-13)
    Article
    Restricted access - publisher's policy
    This study on cold-air pool formation in the wide Cerdanya Valley in the Pyrenees mountain range was conducted using available observational information from September 2010 to August 2014. Cold-air pools occur during almost ...
  • Computational fluid dynamics modeling of impinging gas-jet systems: I. Assessment of eddy viscosity models 

    Coussirat Núñez, Miguel Gustavo; van Beeck, J; Mestres Ridge, Marc; Egusquiza Estévez, Eduard; Buchlin, J-M; Escaler Puigoriol, Francesc Xavier (2005-07-15)
    Article
    Restricted access - publisher's policy
    Computational fluid dynamics plays an important role in engineering design. To gain insight into solving problems involving complex industrial flows, such as impinging gas-jet systems (IJS), an evaluation of several eddy ...
  • Computational fluid dynamics modeling of impinging gas-jet systems: II. Application to an industrial cooling system device 

    Coussirat Núñez, Miguel Gustavo; van Beeck, J; Mestres Ridge, Marc; Egusquiza Estévez, Eduard; Buchlin, J-M; Valero Ferrando, Ma. del Carmen (2005-07-15)
    Article
    Restricted access - publisher's policy
    A numerical analysis of the flow behavior in industrial cooling systems based on arrays of impinging jets has been performed, using several eddy viscosity models to determine their modeling capabilities. For the cooling ...