Ara es mostren els items 1-20 de 44

    • 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
      Accés obert
      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 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
      Accés obert
      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
      Accés restringit per política de l'editorial
      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 ...
    • An OpenCL-based parallel CFD code for simulations on hybrid systems with massively-parallel accelerators 

      Gorobets, Andrei; Trias Miquel, Francesc Xavier; Oliva Llena, Asensio (Elsevier, 2013)
      Text en actes de congrés
      Accés obert
      A parallel finite-volume CFD algorithm for modeling of incompressible flows on hybrid supercomputers is presented. It is based on a symmetry-preserving high-order numerical scheme for structured meshes. A multilevel ...
    • 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)
      Comunicació de congrés
      Accés restringit per política de l'editorial
      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 ...
    • 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)
      Text en actes de congrés
      Accés restringit per política de l'editorial
      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
      Accés obert
      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. ...
    • Building proper invariants for large eddy simulation 

      Trias Miquel, Francesc Xavier; Folch, David; Gorobets, Andrei; Oliva Llena, Asensio (Springer, 2015)
      Text en actes de congrés
      Accés restringit per política de l'editorial
    • Building proper invariants for subgrid-scale eddy-viscosity models 

      Trias Miquel, Francesc Xavier; Folch, David; Gorobets, Andrei; Oliva Llena, Asensio (2015)
      Text en actes de congrés
      Accés restringit per política de l'editorial
      Since direct simulations of the incompressible Navier-Stokes equations are limited to relatively low-Reynolds numbers, dynamically less complex mathematical formulations are necessary for coarse-grain simulations. ...
    • Direct numerical simulation of a differentially heated cavity of aspect ratio 4 with Rayleigh numbers up to 10(11) - Part I: Numerical methods and time-averaged flow 

      Trias Miquel, Francesc Xavier; Gorobets, Andrei; Soria Guerrero, Manel; Oliva Llena, Asensio (2010-01-31)
      Article
      Accés restringit per política de l'editorial
      A set of direct numerical simulations of a differentially heated cavity of aspect ratio 4 with adiabatic horizontal walls is presented. The five configurations selected here (Rayleigh numbers based on the cavity height ...
    • Direct numerical simulation of a differentially heated cavity of aspect ratio 4 with Rayleigh numbers up to 10(11) - Part II: Heat transfer and flow dynamics 

      Trias Miquel, Francesc Xavier; Gorobets, Andrei; Soria Guerrero, Manel; Oliva Llena, Asensio (2010-01-31)
      Article
      Accés restringit per política de l'editorial
      This is the second of a two-part paper on five direct numerical simulations of a differentially heated cavity of aspect ratio 4 with adiabatic horizontal walls (Rayleigh numbers based on the cavity height. The numerical ...
    • Direct numerical simulation of turbulent flows with parallel algorithms for various computing architectures 

      Gorobets, Andrei; Trias Miquel, Francesc Xavier; Borrell Pol, Ricard; Oyarzun Altamirano, Guillermo; Oliva Llena, Asensio (International Association for Computational Mechanics (IACM), 2014)
      Text en actes de congrés
      Accés restringit per política de l'editorial
      The purpose of the work is twofold. Firstly, it is devoted to the development of efficient parallel algorithms for large-scale simulations of turbulent flows on different supercomputer architectures. It reports experience ...
    • DNS and regularization modeling of a turbulent differentially heated cavity of aspect ratio 5 

      Trias Miquel, Francesc Xavier; Gorobets, Andrei; Oliva Llena, Asensio; Pérez Segarra, Carlos David (2013-01-15)
      Article
      Accés obert
      This work is devoted to the study of turbulent natural convection flows in differentially heated cavities. The adopted configuration corresponds to an airfilled (Pr = 0.7) cavity of aspect ratio 5 and Rayleigh number Ra ...
    • DNS of turbulent natural convection flows on the MareNostrum supercomputer 

      Trias Miquel, Francesc Xavier; Gorobets, Andrei; Soria Guerrero, Manel; Oliva Llena, Asensio (2009)
      Article
      Accés restringit per política de l'editorial
      A code for the direct numerical simulation (DNS) of incompressible turbulent flows that provides a fairly good scalability for a wide range of computer architectures has been developed. The spatial discretization of the ...
    • Efficiency of large-scale CFD simulations on modern supercomputers using thousands of CPUS and hybrid MPI+OPENMP parallelization 

      Gorobets, Andrei; Borrell Pol, Ricard; Trias Miquel, Francesc Xavier; Kozubskaya, T.K.; Oliva Llena, Asensio (2010)
      Comunicació de congrés
      Accés restringit per política de l'editorial
      This work represents an experience in using the hybrid parallel model to perform large-scale DNS. Advantages of the hybrid approach compared to the MPI-only approach are presented and discussed. The use of OpenMP in addition ...
    • Efficient CFD code implementation for the ARM-based Mont-Blanc architecture 

      Oyarzun Altamirano, Guillermo; Borrell Pol, Ricard; Gorobets, Andrei; Mantovani, Filippo; Oliva Llena, Asensio (Elsevier, 2017-09-20)
      Article
      Accés obert
      Since 2011, the European project Mont-Blanc has been focused on enabling ARM-based technology for HPC, developing both hardware platforms and system software. The latest Mont-Blanc prototypes use system-on-chip (SoC) devices ...
    • Fine-scale dynamics in turbulent Rayleigh-Bénard convection 

      Dabbagh, Firas; Trias Miquel, Francesc Xavier; Gorobets, Andrei; Oliva Llena, Asensio (Begell House, 2015)
      Text en actes de congrés
      Accés restringit per política de l'editorial
      Small-scale universal features captured normally in many turbulent flows have been reviewed in Rayleigh-Bénard convection. Namely, dynamical Lagrangian representations of the velocity gradient tensor invariants have displayed ...
    • From extruded-2D to fully-3D geometries for DNS: a multigrid-based extension of the Poisson solver 

      Gorobets, Andrei; Trias Miquel, Francesc Xavier; Soria Guerrero, Manel; Pérez Segarra, Carlos David; Oliva Llena, Asensio (2010)
      Article
      Accés restringit per política de l'editorial
      Direct numerical simulation (DNS) of incompressible flows is an essential tool for improving the understanding of the physics of turbulence and for the development of better turbulence models. The Poisson equation, the ...
    • Hybrid MPI+OpenMP parallelization of a Navier-Stokes solver for large-scale DNS 

      Gorobets, Andrei; Trias Miquel, Francesc Xavier; Borrell Pol, Ricard; Soria Guerrero, Manel; Oliva Llena, Asensio (2011)
      Comunicació de congrés
      Accés restringit per política de l'editorial
      This work presents a parallel Navier-Stokes solver for the large-scale direct numerical simulation (DNS) of incompressible flows with one periodic direction. It is based on a scalable Poisson solver that combines an FFT ...
    • Hybrid MPI+OpenMP parallelization of an FFT-based 3D Poisson solver that can reach 100000 CPU cores 

      Gorobets, Andrei; Trias Miquel, Francesc Xavier; Borrell Pol, Ricard; Soria Guerrero, Manel; Oliva Llena, Asensio (2011)
      Text en actes de congrés
      Accés obert
      This work is devoted to the development of efficient parallel algorithms for the direct numerical simulation (DNS) of incompressible flows on modern supercomputers. A Poisson solver for problems with one uniform periodic ...