Implicit explicit Runge-Kutta (IMEX-RK) time discretization methods are very popular when solving stiff kinetic equations. In the work of Hu and Zhang in [J. Sci. Comput. 73 (2017) 797-818], an asymptotic analysis shows that a specific class of high-order IMEX-RK schemes can accurately capture the Navier-Stokes limit without needing to resolve the small scales dictated by the Knudsen number. In this work, we extend the asymptotic analysis to general IMEX-RK schemes, known in literature as Type I and Type II. We further introduce some IMEX-RK methods developed by Boscarino and Pareschi [J. Comput. Appl. Math. 316 (2017) 60-73 to attain uniform accuracy in the wide range of Knudsen numbers. Several numerical examples are presented to verify the validity of the obtained theoretical results and the effectiveness of the methods.
Asymptotic analysis of high order IMEX-RK methods for ES-BGK model at Navier-Stokes level
Boscarino S.;Cho S. Y.
2026-01-01
Abstract
Implicit explicit Runge-Kutta (IMEX-RK) time discretization methods are very popular when solving stiff kinetic equations. In the work of Hu and Zhang in [J. Sci. Comput. 73 (2017) 797-818], an asymptotic analysis shows that a specific class of high-order IMEX-RK schemes can accurately capture the Navier-Stokes limit without needing to resolve the small scales dictated by the Knudsen number. In this work, we extend the asymptotic analysis to general IMEX-RK schemes, known in literature as Type I and Type II. We further introduce some IMEX-RK methods developed by Boscarino and Pareschi [J. Comput. Appl. Math. 316 (2017) 60-73 to attain uniform accuracy in the wide range of Knudsen numbers. Several numerical examples are presented to verify the validity of the obtained theoretical results and the effectiveness of the methods.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
