Special Issue "Large-Eddy Simulations of Turbulent Flows"

A special issue of Energies (ISSN 1996-1073).

Deadline for manuscript submissions: 20 December 2019.

Special Issue Editors

Prof. Dr. Assensi Oliva
E-Mail Website
Guest Editor
Heat and Mass Transfer Technological Center, Technical University of Catalonia, ESEIAAT, Colom 11, Terrassa (Barcelona) 08222, Spain
Interests: heat and mass transfer; CFD; large-eddy simulation; HPC; multiphase flows; numerical methods
Prof. Dr. F. Xavier Trias
E-Mail Website
Guest Editor
Heat and Mass Transfer Technological Center, Technical University of Catalonia, ESEIAAT, Colom 11, Terrassa (Barcelona) 08222, Spain
Interests: turbulence modeling; large-eddy simulation; numerical methods; CFD; parallel computing; direct numerical simulation

Special Issue Information

Dear colleagues,

The Navier-Stokes (NS) equations are an excellent mathematical model for turbulent flows. However, direct simulations at high Reynolds numbers are not feasible yet because the non-linear convective term produces far too many scales of motion. Hence, in the foreseeable future, numerical simulations of turbulent flows will have to resort to small-scale models. In this regard, large-eddy simulation (LES) equations result from filtering the NS equations in space. The effect of the under-resolved scales is then given by the subgrid stress (SGS) tensor that depends on both the filtered and the unfiltered velocity. Then, the famous closure problem in LES basically consists of approximating the SGS tensor with a tensor in terms of the (resolved) filtered velocity. In this way, the dynamical complexity of the NS equations is significantly reduced, resulting in a new set of PDE that are more amenable to being numerically solved on a coarse mesh. Over the past decades, the field of LES has drastically evolved together with the never-ending growth of computational capacity, gaining interest for a wider and wider range of applications. In this context, the objective of this Special Issue of Energies is to bring together people working on advanced, cutting-edge methods for the LES of turbulent flows but also on applications where LES techniques are allowing one to explore new frontiers. The scope includes, but is not limited to the following:

  • LES fundamentals;
  • Numerical methods for LES;
  • Wall-modeling techniques;
  • Hybrid RANS-LES methods;
  • Heat and mass transfer problems;
  • Multiphase flows;
  • Combustion;
  • Environmental and geophysical applications;
  • Industrial applications.

Prof. Dr. Assensi Oliva
Prof. Dr. F. Xavier Trias
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Energies is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Turbulence
  • Large-eddy simulation
  • Turbulence modeling
  • Subgrid-scale model
  • Computational fluid dynamics
  • Wall modeling
  • Hybrid RANS-LES

Published Papers (1 paper)

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Research

Open AccessArticle
Numerical Investigation of Flow through a Valve during Charge Intake in a DISI -Engine Using Large Eddy Simulation
Energies 2019, 12(13), 2620; https://doi.org/10.3390/en12132620 - 08 Jul 2019
Cited by 1
Abstract
Apart from electric vehicles, most internal combustion (IC) engines are powered while burning petroleum-based fossil or alternative fuels after mixing with inducted air. Thereby the operations of mixing and combustion evolve in a turbulent flow environment created during the intake phase and then [...] Read more.
Apart from electric vehicles, most internal combustion (IC) engines are powered while burning petroleum-based fossil or alternative fuels after mixing with inducted air. Thereby the operations of mixing and combustion evolve in a turbulent flow environment created during the intake phase and then intensified by the piston motion and influenced by the shape of combustion chamber. In particular, the swirl and turbulence levels existing immediately before and during combustion affect the evolution of these processes and determine engine performance, noise and pollutant emissions. Both the turbulence characteristics and the bulk flow pattern in the cylinder are strongly affected by the inlet port and valve design. In the present paper, large eddy simulation (LES) is appraised and applied to studying the turbulent fluid flow around the intake valve of a single cylinder IC-engine as represented by the so called magnetic resonance velocimetry (MRV) flow bench configuration with a relatively large Reynolds number of 45,000. To avoid an intense mesh refinement near the wall, various subgrid scale models for LES; namely the Smagorinsky, wall adapting local eddy (WALE) model, SIGMA, and dynamic one equation models, are employed in combination with an appropriate wall function. For comparison purposes, the standard RANS (Reynolds-averaged Navier–Stokes) k- ε model is also used. In terms of a global mean error index for the velocity results obtained from all the models, at first it turns out that all the subgrid models show similar predictive capability except the Smagorinsky model, while the standard k- ε model experiences a higher normalized mean absolute error (nMAE) of velocity once compared with MRV data. Secondly, based on the cost-accuracy criteria, the WALE model is used with a fine mesh of ≈39 millions control volumes, the averaged velocity results showed excellent agreement between LES and MRV measurements, revealing the high prediction capability of the suggested LES tool for valve flows. Thirdly, the turbulent flow across the valve curtain clearly featured a back flow resulting in a high speed intake jet in the middle. Comprehensive LES data are generated to carry out statistical analysis in terms of (1) evolution of the turbulent morphology across the valve passage relying on the flow anisotropy map, (2) integral turbulent scales along the intake-charge stream, (3) turbulent flow properties such as turbulent kinetic energy, turbulent velocity and its intensity within the most critical zone in intake-port and along the port length, it further transpires that the most turbulence are generated across the valve passage and these are responsible for the in-cylinder turbulence. Full article
(This article belongs to the Special Issue Large-Eddy Simulations of Turbulent Flows)
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