Now showing items 1-20 of 85

    • 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 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 Projected Ghost Fluid Method for a mimetic approach for extreme contrast interfaces in multiphase flows 

      Valle Marchante, Nicolás; Trias Miquel, Francesc Xavier; Castro González, Jesús; Oliva Llena, Asensio (2018)
      Conference report
      Restricted access - publisher's policy
      In the context of a multimaterial domain, the GFM for the Laplacian operator is reformulated from an algebraic perspective, where operators are represented by matrices. From this perspective, a whole new level of analysis ...
    • A pure virtual approach for managing platform portability on hybrid supercomputers 

      Álvarez Farré, Xavier; Gorobets, Andrey; Alsati Baldellou, Àdel; Trias Miquel, Francesc Xavier (2019)
      Conference report
      Restricted access - publisher's policy
      Commonly, the development of scientific computing software follows a stencilbased approach: the numerical methods and algorithms are introduced into computing systems through stencil data structures and sweeps (i.e. ...
    • A self-adaptive strategy for the time integration of navier-stokes equations 

      Trias Miquel, Francesc Xavier; Lehmkuhl Barba, Oriol (2011-08)
      Article
      Restricted access - publisher's policy
      An efficient self-adaptive strategy for the explicit time integration of Navier-Stokes equations is presented. Unlike the conventional explicit integration schemes, it is not based on a standard CFL condition. Instead, the ...
    • 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 ...
    • A simple optimization approach for the insulation thickness distribution in household refrigerators 

      Trias Miquel, Francesc Xavier; Oliet Casasayas, Carles; Rigola Serrano, Joaquim; Pérez Segarra, Carlos David (Elsevier, 2018-09)
      Article
      Open Access
      Determination of the optimal insulation thickness is of great relevance in many thermal engineering applications. In this paper, a simple optimization strategy based on the Lagrange multipliers is presented. The optimal ...
    • A time-average filtering technique to improve the efficiency of two-layer wall models for large eddy simulation in complex geometries 

      Calafell Sandiumenge, Joan; Trias Miquel, Francesc Xavier; Lehmkuhl Barba, Oriol; Oliva Llena, Asensio (Elsevier, 2019-06-30)
      Article
      Restricted access - publisher's policy
      Two-Layer wall models have been recurrently studied since they represent a good physical model for Large Eddy Simulations with underresolved wall regions. Specifically, those based on the Reynolds Averaged Navier-Stokes ...
    • Algebraic implementation of a flux limiter for heterogeneous computing 

      Valle Marchante, Nicolás; Álvarez Farré, Xavier; Trias Miquel, Francesc Xavier; Castro González, Jesús; Oliva Llena, Asensio (2018)
      Conference report
      Restricted access - publisher's policy
    • An efficient Two-Layer wall model for accurate numerical simulations of aeronautical applications 

      Calafell Sandiumenge, Joan; Trias Miquel, Francesc Xavier; Oliva Llena, Asensio (2019)
      Conference report
      Open Access
      Two-Layer wall models have been widely studied since they allow wall modeled Large Eddy Simulationsof general non-equilibrium flows. However, they are plagued by two persistent problems, the "log-layermismatch" and the ...
    • An efficient two-layer wall model for high Reynolds number large eddy simulation 

      Calafell Sandiumenge, Joan; Trias Miquel, Francesc Xavier; Oliva Llena, Asensio (International Centre for Numerical Methods in Engineering (CIMNE), 2018)
      Conference report
      Restricted access - publisher's policy
      Wall-bounded flows at high Reynolds number are an important research field given that they are present in many important industrial applications. Nonetheless, the use of accurate numerical methodologies such as Large Eddy ...
    • An energy-preserving level set method for multiphase flows 

      Valle Marchante, Nicolás; Trias Miquel, Francesc Xavier; Castro González, Jesús (2020-01-01)
      Article
      Restricted access - publisher's policy
      The computation of multiphase flows presents a subtle energetic equilibrium between potential (i.e., surface) and kinetic energies. The use of traditional interface-capturing schemes provides no control over such a dynamic ...
    • An eulerian-lagrangian modeling of fluidized bed 

      Zhang, Hao; Yuan-Qiang, Tan; Dong-Min, Yang; Trias Miquel, Francesc Xavier; Sheng, Yong; Oliva Llena, Asensio (2013)
      Conference report
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      The particle motions in a fluidized bed were numerically simulated using a Eulerian-Lagrangian model. The solid phase was modelled via the Discrete Element Method (DEM) while the hydrodynamic model of the fluid phase was ...
    • 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)
      Conference report
      Open Access
      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 ...
    • Assessment and comparison of a recent kinematic sensitive subgrid length scale in Hybrid RANS-LES 

      Pont Vilchez, Arnau; Trias Miquel, Francesc Xavier; Revell, Alistair; Oliva Llena, Asensio (Springer Nature, 2020)
      Conference report
      Restricted access - publisher's policy
      A recent kinematic sensitive subgrid length scale, Δlsq, initially developed for LES applications, is now considered for DES. Even though it is presented as a subgrid length scale, instead of a grey area mitigation (GAM) ...
    • Assessment of LES techniques for mitigating the Grey Area in DDES models 

      Pont Vilchez, Arnau; Santos Serrano, Daniel; Trias Miquel, Francesc Xavier; Duben, Alexey; Revell, Alistair; Oliva Llena, Asensio (2019)
      Conference report
      Open Access
      The slow RANS-LES transition is a well-known shortcoming in hybrid turbulence models such as DelayedDetached Eddy Simulation (DDES). The present work assesses the feasibility of 2D sensitive LES models for naturally ...
    • 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 ...
    • Building a new subgrid characteristic length for LES 

      Trias Miquel, Francesc Xavier; Gorobets, Andrey; Duben, Alexey; Oliva Llena, Asensio (Keldysh Institute of Applied Mathematics, 2016)
      Conference report
      Restricted access - publisher's policy
    • 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. ...