Achievable efficiency of numerical methods for simulations of solar surface convection

We investigate the achievable efficiency of both the time and the space discretisation methods used in Antares for mixed parabolic–hyperbolic problems. We show that the fifth order variant of WENO combined with a second order Runge–Kutta scheme is not only more accurate than standard first and second order schemes, but also more efficient taking the computation time into account. Then, we calculate the error decay rates of WENO with several explicit Runge–Kutta schemes for advective and diffusive problemswith smooth and non-smooth initial conditions.With this data, we estimate the computational costs of three-dimensional simulations of stellar surface convection and show that SSPRK(3,2) is the most efficient scheme considered in this comparison. © 2014 Elsevier B.V. All rights reserved. The simulation code Antares [1] was developed for the simulation of solar and stellar surface convection. Recently it has also been applied to many other astrophysical problems (e.g. [2,3]). In this code, the Navier–Stokes equations usually without magnetic field and with radiative transfer (radiation hydrodynamics, RHD) are solved in the form