|Preprint-No.:||< 389 >||Published in:||March 2014||PDF-File:||IGPM389.pdf|
|Title:||IMEX Large Time Step Finite Volume Methods for Low Froude Number Shallow Water Flows|
|Authors:||Georgij Bispen, Koottungal Revi Arun, Maria Lukáčová-Medviďová, Sebastian Noelle|
We present new large time step methods for the shallow water ﬂows in the low Froude number limit. In order to take into account multiscale phenomena that typically appear in geophysical ﬂows nonlinear ﬂuxes are split into a linear part governing the gravitational waves and the nonlinear advection. We propose to ap- proximate fast linear waves implicitly in time and in space by means of a genuinely multidimensional evolution operator. On the other hand, we approximate nonlinear advection part explicitly in time and in space by means of the method of charac- teristics or some standard numerical ﬂux function. Time integration is realized by the implicit-explicit (IMEX) method. We apply the IMEX Euler scheme, two step Runge Kutta Cranck Nicolson scheme, as well as the semi-implicit BDF scheme and prove their asymptotic preserving property in the low Froude number limit. Numerical experiments demonstrate stability, accuracy and robustness of these new large time step ﬁnite volume schemes with respect to small Froude number.
|Keywords:||low Froude number ﬂows, asymptotic preserving schemes, shallow water equations, large time step, semi-implicit approximation, evolution Galerkin schemes|
|Publication:||Communication in Computational Physics |
Volume 16 (2014), pp. 307-347.