API Reference

AnalysisCallback(semi; interval=0,
                       save_analysis=false,
                       output_directory="out",
                       analysis_filename="analysis.dat",
                       extra_analysis_errors=Symbol[],
                       extra_analysis_integrals=(),
                       analysis_pointwise=())

Analyze a numerical solution every interval time steps and print the results to the screen. If save_analysis, the results are also saved in joinpath(output_directory, analysis_filename).

Additional errors can be computed, e.g. by passing extra_analysis_errors = (:l2_error_primitive, :linf_error_primitive) or extra_analysis_errors = (:conservation_error,).

If you want to omit the computation (to safe compute-time) of the default_analysis_errors, specify analysis_errors = Symbol[]. Note: default_analysis_errors are :l2_error and :linf_error for all equations. If you want to compute extra_analysis_errors such as :conservation_error solely, i.e., without :l2_error, :linf_error you need to specify analysis_errors = [:conservation_error] instead of extra_analysis_errors = [:conservation_error].

Further scalar functions func in extra_analysis_integrals are applied to the numerical solution and integrated over the computational domain. Some examples for this are entropy, energy_kinetic, energy_internal, and energy_total. You can also write your own function with the same signature as the examples listed above and pass it via extra_analysis_integrals. The default analysis_integrals is (entropy_timederivative,). You can also request extra_analysis_integrals such as LiftCoefficientPressure or DragCoefficientPressure by constructing an AnalysisSurfaceIntegral with one of the previously mentioned functions.

Similarly, pointwise, i.e., per quadrature/interpolation point, quantities such at SurfacePressureCoefficient or SurfaceFrictionCoefficient can be computed. Instances of these need to be passed into AnalysisSurfacePointwise which is then in turn passed to analysis_pointwise.

See the developer comments about Trixi.analyze, Trixi.pretty_form_utf, and Trixi.pretty_form_ascii for further information on how to create custom analysis quantities.

In addition, the analysis callback records and outputs a number of quantities that are useful for evaluating the computational performance, such as the total runtime, the performance index (time/DOF/rhs!), the time spent in garbage collection (GC), or the current memory usage (alloc'd memory).

AnalysisSurfacePointwise{Variable, NBoundaries}(boundary_symbol_or_boundary_symbols,
                                                variable, output_directory = "out")

This struct is used to compute pointwise surface values of a quantity of interest variable alongside the boundary/boundaries associated with particular names given in boundary_symbols. For instance, this can be used to compute the surface pressure coefficient SurfacePressureCoefficient or surface friction coefficient SurfaceFrictionCoefficient of e.g. an 2D airfoil with the boundary names :AirfoilTop, :AirfoilBottom which would be supplied as boundary_symbols = (:AirfoilTop, :AirfoilBottom). A single boundary name can also be supplied, e.g. boundary_symbols = (:AirfoilTop,).

• boundary_symbols::NTuple{NBoundaries, Symbol}: Name(s) of the boundary/boundaries where the quantity of interest is computed
• variable::Variable: Quantity of interest, like lift or drag
• output_directory = "out": Directory where the pointwise value files are stored.

SurfaceFrictionCoefficient(rhoinf, uinf)

Compute the surface skin friction coefficient

\[C_f \coloneqq \frac{\boldsymbol \tau_w \boldsymbol n^\perp} {0.5 \rho_{\infty} U_{\infty}^2 L_{\infty}}\]

based on the wall shear stress vector $\tau_w$ along a boundary. Supposed to be used in conjunction with AnalysisSurfacePointwise which stores the boundary information and semidiscretization.

• rho_inf::Real: Free-stream density
• u_inf::Real: Free-stream velocity

SurfacePressureCoefficient(p_inf, rho_inf, u_inf)

Compute the surface pressure coefficient

\[C_p \coloneqq \frac{p - p_{\infty}} {0.5 \rho_{\infty} U_{\infty}^2}\]

based on the pressure distribution along a boundary. Supposed to be used in conjunction with AnalysisSurfacePointwise which stores the boundary information and semidiscretization.

• p_inf::Real: Free-stream pressure
• rho_inf::Real: Free-stream density
• u_inf::Real: Free-stream velocity

examples_dir()

Return the directory where the example files provided with TrixiAero.jl are located. If TrixiAero.jl is installed as a regular package (with ]add TrixiAero), these files are read-only and should not be modified. To find out which files are available, use, e.g., readdir:

Examples

readdir(examples_dir())