Added example elixir for the multicomponent Euler equations on struct…

…ured meshes.

examples/structured_2d_dgsem/elixir_eulermulti_convergence_ec.jl

@@ -0,0 +1,58 @@
+
+using OrdinaryDiffEq
+using Trixi
+
+###############################################################################
+# semidiscretization of the compressible Euler multicomponent equations
+equations = CompressibleEulerMulticomponentEquations2D(gammas        = (1.4, 1.4),
+                                                       gas_constants = (0.4, 0.4))
+
+initial_condition = initial_condition_convergence_test
+
+volume_flux = flux_ranocha
+solver = DGSEM(polydeg=3, surface_flux=flux_ranocha,
+               volume_integral=VolumeIntegralFluxDifferencing(volume_flux))
+
+cells_per_dimension = (32, 32)
+coordinates_min = (-1.0, -1.0)
+coordinates_max = ( 1.0,  1.0)
+mesh = StructuredMesh(cells_per_dimension, coordinates_min, coordinates_max)
+
+
+semi = SemidiscretizationHyperbolic(mesh, equations, initial_condition, solver,
+                                    source_terms=source_terms_convergence_test)
+
+
+###############################################################################
+# ODE solvers, callbacks etc.
+
+tspan = (0.0, 0.4)
+ode = semidiscretize(semi, tspan)
+
+summary_callback = SummaryCallback()
+
+analysis_interval = 100
+analysis_callback = AnalysisCallback(semi, interval=analysis_interval)
+
+alive_callback = AliveCallback(analysis_interval=analysis_interval)
+
+save_solution = SaveSolutionCallback(interval=100,
+                                     save_initial_solution=true,
+                                     save_final_solution=true,
+                                     solution_variables=cons2prim)
+
+stepsize_callback = StepsizeCallback(cfl=0.5)
+
+callbacks = CallbackSet(summary_callback,
+                        analysis_callback, alive_callback,
+                        save_solution,
+                        stepsize_callback)
+
+
+###############################################################################
+# run the simulation
+
+sol = solve(ode, CarpenterKennedy2N54(williamson_condition=false),
+            dt=1.0, # solve needs some value here but it will be overwritten by the stepsize_callback
+            save_everystep=false, callback=callbacks);
+summary_callback() # print the timer summary