Editorial: IFP Energies nouvelles International Conference LES4ICE 2014 – Large-Eddy Simulation for Internal Combustion Engine Flows

Abstract

Further improving the environmental performances of Internal Combustion Engines (ICE) increasingly requires moving beyond traditional multidimensional simulation tools based on a cycle averaged approach (Reynolds-Averaged Navier–Stokes, RANS), and to reliably predict and control individual engine cycles under realistic operating conditions. Large-Eddy Simulation (LES) offers this unique potential by predicting spatially filtered flow realizations, thus opening up new perspectives for extending the scope of application of Computational Fluid Dynamics (CFD) for ICE. Since its 1 edition in 2008, the LES4ICE conference provides a forum for exchange concerning research and development of LES and related experimental techniques for their application to ICE flows. It brings together researchers and engineers working in the field of piston engine combustion to debate the state of the art in LES applied to ICE and examine advanced experimental techniques capable of supporting and validating its development. The present special issue proposes an extract from the contributions to the 2014 edition of LES4ICE, following a selection by the conference’s Scientific Committee. The selected four articles provide a view on some recent advances in the domain of LES and related experimental techniques, and on their application to ICE flows. The study of Cyclic Combustion Variability (CCV) in Spark-Ignition Engines (SIE) has become a prominent topic for LES research in the past decade. It has been demonstrated how combining advanced optical diagnostics and state-of-the-art LES can allow identifying the causes of CCV, and that the acquired understanding could efficiently be capitalized in the form of reduced models for 1D CFD simulations of complete engine systems. This on-going research opened exciting perspectives for the application of LES to other yet poorly understood and mastered non-cyclic phenomena in SIE, as in particular the link between CCV and engine knock. A longstanding issue when studying the causes of CCV in SI engines is the relative importance of the variability of large-scale coherent structures, and of small scale turbulent fluctuations. A method aiming at addressing this question was proposed by S. Buhl, F. Hartmann and C. Hasse, in their contribution “Identification of Large-Scale Structure Fluctuations in IC Engines using POD-Based Conditional Averaging” [1]. They propose a method combining POD and conditional averaging, and discuss its application to the analysis of the origins of CCV for two different LES datasets. Oil & Gas Science and Technology – Rev. IFP Energies nouvelles (2016) 71, E1 C. Angelberger and C. Mounaim-Rousselle, published by IFP Energies nouvelles, 2016 DOI: 10.2516/ogst/2015048 IFP Energies nouvelles International Conference Rencontres Scientifiques d'IFP Energies nouvelles