elixir_euler_flux_diff.jl

using OrdinaryDiffEqLowStorageRK
using Trixi

# Up to version 0.13.0, `max_abs_speed_naive` was used as the default wave speed estimate of
# `const flux_lax_friedrichs = FluxLaxFriedrichs(), i.e., `FluxLaxFriedrichs(max_abs_speed = max_abs_speed_naive)`.
# In the `StepsizeCallback`, though, the less diffusive `max_abs_speeds` is employed which is consistent with `max_abs_speed`.
# Thus, we exchanged in PR#2458 the default wave speed used in the LLF flux to `max_abs_speed`.
# To ensure that every example still runs we specify explicitly `FluxLaxFriedrichs(max_abs_speed_naive)`.
# We remark, however, that the now default `max_abs_speed` is in general recommended due to compliance with the 
# `StepsizeCallback` (CFL-Condition) and less diffusion.
surface_flux = FluxLaxFriedrichs(max_abs_speed_naive)
volume_flux = flux_ranocha
dg = DGMulti(polydeg = 3, element_type = Line(), approximation_type = Polynomial(),
             surface_integral = SurfaceIntegralWeakForm(surface_flux),
             volume_integral = VolumeIntegralFluxDifferencing(volume_flux))

equations = CompressibleEulerEquations1D(1.4)

initial_condition = initial_condition_convergence_test
source_terms = source_terms_convergence_test

cells_per_dimension = (8,)
mesh = DGMultiMesh(dg, cells_per_dimension,
                   coordinates_min = (-1.0,), coordinates_max = (1.0,), periodicity = true)
semi = SemidiscretizationHyperbolic(mesh, equations, initial_condition, dg;
                                    source_terms = source_terms)

tspan = (0.0, 1.1)
ode = semidiscretize(semi, tspan)

summary_callback = SummaryCallback()
alive_callback = AliveCallback(alive_interval = 10)
analysis_interval = 100
analysis_callback = AnalysisCallback(semi, interval = analysis_interval, uEltype = real(dg))
save_solution = SaveSolutionCallback(interval = 100,
                                     solution_variables = cons2prim)
callbacks = CallbackSet(summary_callback,
                        analysis_callback,
                        alive_callback, save_solution)

###############################################################################
# run the simulation

sol = solve(ode, CarpenterKennedy2N54(williamson_condition = false);
            dt = 0.5 * estimate_dt(mesh, dg),
            ode_default_options()...,
            callback = callbacks);