Browsing by Subject "Eddies"

Now showing items 1-20 of 30

    • A low-dissipation finite element scheme for scale resolving simulations of turbulent flows 

      Lehmkuhl Barba, Oriol; Houzeaux, Guillaume; Owen, Herbert; Chrysokentis, Giorgios; Rodríguez Pérez, Ivette María (2019-08-01)
      Article
      Open Access
      The present work extends the conservative convective scheme proposed by Charnyi et al. (2017) [13], originally formulated for mixed finite elements and tested in laminar flows, to equal order finite elements. A non-incremental ...

    • 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
      Open Access
      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 ...

    • 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 ...

    • 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 ...

    • 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 ...

    • Data-driven prediction of flow parameters in a ventilated cavity using high-fidelity CFD simulations 

      Morozova, Nina; Trias Miquel, Francesc Xavier; Capdevila Paramio, Roser; Oliva Llena, Asensio (International Building Performance Simulation Association (IBPSA), 2021)
      Conference report
      Restricted access - publisher's policy
      In this study, we develop a machine-learning-based data-driven model, which predicts comfort-related flow parameters in a ventilated room. The model is based on the results of high-fidelity computational fluid dynamics ...

    • Discovering new scaling laws in turbulent boundary layers via multi-expression programming 

      Simó Muñoz, Irene (Universitat Politècnica de Catalunya, 2022-07-18)
      Bachelor thesis
      Open Access
      Flow turbulence modeling is an expensive computational operation that is often run with simulations using physical simplifications to reduce the cost. Large-eddy simulations (LES) of turbulent flow often make use of wall ...

    • DNS and LES on unstructured grids: playing with matrices to preserve symmetries using a minimal set of algebraic kernels 

      Trias Miquel, Francesc Xavier; Álvarez Farré, Xavier; Alsalti Baldellou, Àdel; Gorobets, Andrei; Oliva Llena, Asensio (Scipedia, 2022)
      Conference report
      Open Access
      The essence of turbulence are the smallest scales of motion. They result from asubtle balance between two differential operators differing in symmetry: The convective operator is skew-symmetric, whereas the diffusive is ...

    • DNS/LES using a minimal set of algebraic Kernels: challenges and opportunities 

      Trias Miquel, Francesc Xavier; Álvarez Farré, Xavier; Alsalti Baldellou, Àdel; Gorobets, Andrei; Oliva Llena, Asensio (Parallel Computational Fluid Dynamics (ParCFD), 2022)
      Conference report
      Restricted access - publisher's policy
      In the last decades, CFD has become a standard design tool in many fields such as automotive, aeronautical and wind power industries. The driven force behind this is the development of numerical techniques in conjunction ...

    • Effects of Rotation on the Flow Structure in a Compressor Cascade 

      Ventosa Molina, Jordi; Koppe, Björn; Lange, Martin; Mailach, Ronald; Fröhlich, Jochen (2022-08-01)
      Article
      Restricted access - publisher's policy
      In turbomachines, rotors and stators differ by the rotation of the former. Hence, half of each stage is directly influenced by rotation effects. The influence of rotation on the flow structure and its impact on the performance ...

    • Effects of Rotation on the Flow Structure in a Compressor Cascade 

      Ventosa Molina, Jordi; Koppe, Björn; Lange, Martin; Mailach, Ronald; Fröhlich, Jochen (American Society of Mechanical Engineers (ASME), 2021)
      Conference report
      Restricted access - publisher's policy
      In turbomachines, rotors and stators differ by the rotation of the former. Hence, half of each stage is directly influenced by rotation effects. The influence of rotation on the flow structure and its impact on the performance ...

    • Evaluation of enhanced gray area mitigation approaches based on jet aeroacoustics 

      Duben, Alexey; Ruano Pérez, Jesús; Gorobets, Andrei; Rigola Serrano, Joaquim; Trias Miquel, Francesc Xavier (2023-02)
      Article
      Open Access
      An investigation of various eddy viscosity models for accurate scale-resolving simulation of aerodynamics and aeroacoustics of a turbulent jet is presented. The models are considered from the perspective of solving the ...

    • Formulation of the Dutch Atmospheric Large-Eddy Simulation (DALES) and overview of its applications 

      Vilà-Guerau de Arellano, Jordi; De Roode, Stephan; Pino González, David; Heus, Thijs; Van Heerwaarden, Chiel C.; Jonker, Harm J.J.; Siebesma, Pier; Axelsen, Simon; Van den Dries, Kees; Geoffroy, Oliver; Moene, Arnold F. (2010-09-30)
      Article
      Open Access
      The current version of the Dutch Atmospheric Large-Eddy Simulation (DALES) is presented. DALES is a large-eddy simulation code designed for studies of the physics of the atmospheric boundary layer, including convective and ...

    • Large eddy simulation of optimal synthetic jet actuation on a SD7003 airfoil in post-stall conditions 

      Monshi Tousi, Navid; Bergadà Granyó, Josep Maria; Mellibovsky Elstein, Fernando (2022-08)
      Article
      Open Access
      Aerodynamic performances may be optimised by the appropriate tuning of Active Flow Control (AFC) parameters. For the first time, we couple Genetic Algorithms (GA) with an unsteady Reynolds-Averaged Navier-Stokes (RANS) ...

    • Large-eddy simulation of cavitating tip leakage vortex structures and dynamics around a NACA0009 hydrofoil 

      Geng, Linlin; Zhang, Desheng; Chen, Jian; Escaler Puigoriol, Francesc Xavier (MDPI, 2021-11-01)
      Article
      Open Access
      The tip leakage vortex (TLV) has aroused great concern for turbomachine performance, stability and noise generation as well as cavitation erosion. To better understand structures and dynamics of the TLV, large-eddy simulation ...

    • Near-Wall Flow in Turbomachinery Cascades—Results of a German Collaborative Project 

      Engelmann, David; Sinkwitz, Martin; di Mare, Francesca; Koppe, Björn; Mailach, Ronald; Ventosa Molina, Jordi; Fröhlich, Jochen; Schubert, Tobias; Niehuis, Reinhard (Multidisciplinary Digital Publishing Institute (MDPI), 2021-05-08)
      Article
      Open Access
      This article provides a summarizing account of the results obtained in the current collabora-tive work of four research institutes concerning near-wall flow in turbomachinery. Specific questions regarding the influences ...

    • New Strategies for Mitigating the Gray Area in Delayed-Detached Eddy Simulation Models 

      Pont Vilchez, Arnau; Duben, Alexey; Gorobets, Andrei; Revell, Alistair; Oliva Llena, Asensio; Trias Miquel, Francesc Xavier (2021-09)
      Article
      Open Access
      This paper presents a new approach for mitigating the unphysical delay in the Reynolds-averaged Navier–Stokes (RANS) to large-eddy simulation (LES) transition, often referred to as the gray area, which is a common issue ...

    • On a Proper Tensor-Diffusivity Model for Large-Eddy Simulation of Buoyancy-Driven Turbulence 

      Trias Miquel, Francesc Xavier; Dabbagh, Firas; Gorobets, Andrei; Oliet Casasayas, Carles (Springer, 2020-03-26)
      Article
      Open Access
      In this work, we aim to shed light to the following research question: can we find a nonlinear tensorial subgrid-scale (SGS) heat flux model with good physical and numerical properties, such that we can obtain satisfactory ...

    • On a proper tensor-diffusivity model for large-eddy simulations of buoyancy driven flows 

      Trias Miquel, Francesc Xavier; Dabbagh, Firas; Gorobets, Andrei; Oliva Llena, Asensio (2019)
      Conference report
      Restricted access - publisher's policy