BGK Polyatomic Model for Rarefied Flows
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In this work we present a new model of BGK type for polyatomic gases. The model incorporates the different relaxation rates of translational, rotational and/or vibrational modes characterizing polyatomic molecules using a BGK-type equation, and additional relaxation equations for the temperatures associated to each internal energy mode. We construct an efficient numerical scheme which is implicit in the relaxation terms, and test the model and the scheme on several problems, confirming the Asymptotic Preserving properties of the scheme, and comparing the results provided by the model with experimental and DSMC simulations, carried out on the full Boltzmann polyatomic equation.
KeywordsKinetic models Polyatomic gas Multi-temperature BGK model AP schemes
Experiments presented in this paper were carried out using the PlaFRIM experimental testbed, being developed under the Inria PlaFRIM development action with support from LABRI and IMB and other entities: Conseil Régional d’Aquitaine, FeDER, Université de Bordeaux and CNRS (see https://plafrim.bordeaux.inria.fr/). This study has been carried out with financial support from the French State, managed by the French National Research Agency (ANR) in the frame of the “Investments for the future” Programme IdEx Bordeaux (ANR-10-IDEX-03-02), Cluster of excellence CPU, and partly by the Italian State under GNCS-INDAM 2015 project “Metodi numerici per la quantificazione dell’incertezza in equazioni iperboliche e cinetiche”.
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