https://hal-univ-pau.archives-ouvertes.fr/hal-02359072Moguen, YannYannMoguenDepartment of Flow, Heat and Combustion Mechanics - UGENT - Universiteit Gent = Ghent UniversityDick, ErikErikDickDepartment of Flow, Heat and Combustion Mechanics - UGENT - Universiteit Gent = Ghent UniversityBruel, PascalPascalBruelCAGIRE - Computational Approximation with discontinous Galerkin methods and compaRison with Experiments - LMAP - Laboratoire de MathÃ©matiques et de leurs Applications [Pau] - UPPA - UniversitÃ© de Pau et des Pays de l'Adour - CNRS - Centre National de la Recherche Scientifique - Inria Bordeaux - Sud-Ouest - Inria - Institut National de Recherche en Informatique et en AutomatiqueSemi-implicit characteristic-based boundary treatment for acoustics in low Mach number flowsHAL CCSD2013Characteristic-based boundary conditionsLow Mach number flowSemi-implicit algorithmAcoustics[PHYS.MECA.MEFL] Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph]Moguen, Yann2019-11-13 15:01:492023-03-24 14:53:132019-11-13 18:15:47enJournal articleshttps://hal-univ-pau.archives-ouvertes.fr/hal-02359072/document10.1016/j.jcp.2013.08.019application/pdf1For low Mach number flow calculation, when acoustic waves have to be captured, semi-implicit methods allow to avoid the time-step limitation that arises when explicit schemes are used. A method is suggested to solve the boundary equations so that the semi-implicitness of the algorithm is maintained, as well as its pressure-velocity coupling. This method is studied theoretically and numerically, in the low Mach number regime. Partially non-reflective characteristic-based boundary conditions, with the linear relaxation form suggested by Rudy and Strikwerda, [J. Comput. Phys. 36 (1980) 55-70], are considered. It is shown that their properties, well known in the framework of explicit schemes, are recovered with the proposed semi-implicit treatment and an acoustic CFL number significantly larger than unity.