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@ARTICLE{AR-CFD-21-61, author = {Malé, Q. and Vermorel, O. and Ravet, F. and Poinsot, T. }, title = {Jet Ignition Prediction in a Zero-Dimensional Pre-Chamber Engine Model}, year = {2021}, doi = {10.1177/14680874211015002}, journal = {International Journal of Engine Research}, abstract = {This paper presents a multi-chamber, multi-zone engine model to predict the ignition of a lean main chamber by a pre-chamber. The two chambers are connected by small cylindrical holes: the flame is ignited in the pre-chamber, hot gases propagate through the holes and ignite the main chamber through Turbulent Jet Ignition (TJI). The model original features are: i) separate balance equations for the pre- and main chambers, ii) a specific model for temperature and composition evolution in the holes and iii) a DNS-based model 1 to predict the ignition of the main chamber fresh gases by the burnt gases turbulent jets exiting the holes. Chemical reactions during TJI are the result of two competing mixing processes: (1) the hot jet gases mix with the fresh main chamber to produce heated zones and (2) at the same time, these hot gases cool down. (1) increases combustion and leads to ignition while (2) decreases it and can prevent ignition. The overall outcome (ignition or failure) is too complex to be modelled simply and the present model relies on recent DNSs of TJI1 which provided a method to predict the occurrence of ignition. Incorporating this DNS information into the engine model allows to predicts whether ignition will occur or not, an information which is not accessible otherwise using simple models. The resulting approach is tested on multiple cases to predict ignition limits for very lean cases, e↵ects of H2 injection into the pre-chamber and optimum size for the holes connecting the two chambers as a function of equivalence ratio.}, keywords = {turbulent jet ignition, pre-chamber ignition, internal combustion engine, multi-zone engine model}, url = {https://doi.org/10.1177/14680874211015002}}

@ARTICLE{AR-PA-21-23, author = {Bauer, M. and Kostler, H. and Ruede, U. }, title = {lbmpy: Automatic code generation for efficient parallel lattice Boltzmann methods}, year = {2021}, volume = {49}, pages = {101269}, doi = {10.1016/j.jocs.2020.101269}, journal = {Journal of Computational Science}, pdf = {https://doi.org/10.1016/j.jocs.2020.101269}}

@ARTICLE{AR-CFD-21-53, author = {Renard, F. and Feng, Y. and Boussuge, J.-F. and Sagaut, P. }, title = {Improved compressible hybrid lattice Boltzmann method on standard lattice for subsonic and supersonic flows}, year = {2021}, number = {April 2021}, volume = {219}, pages = {104867 }, issn = {0045-7930}, doi = {10.1016/j.compfluid.2021.104867}, abstract = {A D2Q9 Hybrid Lattice Boltzmann Method (HLBM) is proposed for the simulation of both compressible subsonic and supersonic flows. This HLBM is an extension of the model of Feng et al. [1], which has been found, via different test cases, to be unstable for supersonic regimes. To circumvent this limitation, we propose:: (1) a new discretization of the lattice closure correction term that makes possible the simulation of supersonic flows, (2) a corrected viscous stress tensor that takes into account polyatomic gases, and (3) a novel discretization of the viscous heat production term fitting with the regularized formalism. The result is a hybrid method that resolves the mass and momentum equations with an LBM algorithm, and resolves the entropy-based energy equation with a finite volume method. This approach fully recovers the physics of the Navier–Stokes–Fourier equations with the ideal gas equation of state, and is valid from subsonic to supersonic regimes. It is then successfully assessed with both smooth flows and flows involving shocks. The proposed model is shown to be an efficient, accurate, and robust alternative to classic Navier–Stokes methods for the simulation of compressible flows}, keywords = {LBM, Compressible High speed flow, Shock waves, Aerodynamic noise}}

@ARTICLE{AR-PA-21-45, author = {Mohanamuraly, P. and Müller, J.D. }, title = {An Adjoint‐assisted Multilevel Multifidelity Method for Uncertainty Quantification And Its Application To Turbomachinery Manufacturing Variability}, year = {2021}, number = {9}, volume = {122}, pages = {2179-2204}, doi = {10.1002/nme.6617}, journal = {International Journal for Numerical Methods in Engineering}, keywords = {Multilevel Multifidelity Monte Carlo, Uncertainty Quantification, Goalbased PCA, Adjoint Sensitivity, Manufacturing Variations}, pdf = {https://doi.org/10.1002/nme.6617}}

@ARTICLE{AR-CFD-21-38, author = {Agostinelli, P.W. and Rochette, B. and Laera, D. and Dombard, J. and Cuenot, B. and Gicquel, L.Y.M. }, title = {Static mesh adaptation for reliable large eddy simulation of turbulent reacting flows}, year = {2021}, number = {3}, volume = {33}, pages = {035141}, doi = {10.1063/5.0040719}, journal = {Physics of Fluids}, abstract = {The design challenge of reliable lean combustors needed to decrease pollutant emissions has clearly progressed with the common use of experiments as well as Large Eddy Simulation (LES) because of its ability to predict the interactions between turbulent flows, sprays, acoustics and flames. However, the accuracy of such numerical predictions depends very often on the user’s experience to choose the most appropriate flow modeling and, more importantly, the proper spatial discretization for a given computational domain. The present work focuses on the last issue and proposes a static mesh refinement strategy based on flow physical quantities. To do so, a combination of sensors based on the dissipation and production of kinetic energy coupled to the flame-position probability is proposed to detect the regions of interest where flow physics happens and grid adaptation is recommended for good LES predictions. Thanks to such measures a local mesh resolution can be achieved in these zones improving the LES overall accuracy while, eventually, coarsening everywhere else in the domain to reduce the computational cost. The proposed mesh refinement strategy is detailed and validated on two reacting-flow problems: a fully premixed bluff-body stabilized flame, i.e. the VOLVO test case, and a partially premixed swirled flame, i.e. the PRECCINSTA burner, which is closer to industrial configurations. For both cases, comparisons of the results with experimental data underline the fact that the predictions of the flame stabilization, and hence the computed velocity and temperature fields, are strongly influenced by the mesh quality and significant improvement can be obtained by applying the proposed strategy}}