Distributed Problem Setups

There are a number of standard problem setups that come with Castro. These can be used as a starting point toward writing your own setup. We organize these into subdirectories by broad type (radiation, hydro, gravity, etc.): The standard categories and some of the included problems are:

  • gravity_tests:

    • DustCollapse: A pressureless cloud collapse that is a standard test problem for gravity. An analytic solution that describes the radius of the sphere as a function of time is found in Colgate and White [31]. This problem is also found in the FLASH User’s Guide.

    • evrard_collapse: This is the collapse of an isothermal spherical gas cloud. This problem was originally discussed in [37]. This implementation of the test comes from section 9.1 of [64].

    • hydrostatic_adjust: Model a 1-d stellar atmosphere (plane-parallel or spherical/self-gravitating) and dump energy in via an analytic heat source and watch the atmosphere’s hydrostatic state adjust in response. This is the counterpart to the Maestro test_basestate unit test.

    • hse_convergence: This is meant to be a simple 1-d test for assessing the convergence of hydro + gravity in maintaining HSE. Convergence can be measured either by looking at the max \(|U|\) in the plotfiles.

    • hydrostatic_adjust: This is a problem that explores the change in a hydrostatic structure due to heating. This was used originally in [21].

    • StarGrav: This problem sets up a single spherical star in hydrostatic equilibrium and is used to assess the ability to maintain HSE.

    • uniform_cube_sphere: This is used to compute the gravitational potential of a perfect cube, for which there is an analytic solution. It tests our isolated boundary conditions. This was demonstrated in [50].

  • hydro_tests:

    • acoustic_pulse: The acoustic pulse problem from [6] used to measure convergence of pure hydrodynamics problems (as used for Castro in [76]).

    • acoustic_pulse_general: a general equation of state version of acoustic_pulse used for measuring convergence in [76].

    • double_bubble: Initialize 1 or 2 bubbles in a stratified atmosphere (isothermal or isentropic) and allow for the bubbles to have the same or a different \(\gamma\) from one another / the background atmosphere. This uses the multigamma EOS. An analogous problem is implemented in Maestro.

    • KH: A Kelvin-Helmholtz shear instability problem.

    • oddeven: A grid-aligned shock hitting a very small density perturbation. This demonstrates the odd-even decoupling problem discussed in [9]. This setup serves to test the castro.hybrid_riemann option to hydrodynamics.

    • RT: A single-model Rayleigh-Taylor instability problem.

    • Sedov: The standard Sedov-Taylor blast wave problem. This setup was used in the first Castro paper [19].

    • Sod: A one-dimensional shock tube setup, including the classic Sod problem. This setup was used in the original Castro paper [19].

    • Sod_stellar: A version of the Sod shock tube for the general stellar equation of state. This setup and the included inputs files was used in [75].

    • toy_convect: A simple nova-like convection problem with an external heating source. This problem shows how to use the model parser to initialize a 1-d atmosphere on the Castro grid, incorporate a custom tagging routine, sponge the fluid above the atmosphere, and write a custom diagnostics routine. A MAESTROeX version of this problem setup also exists.

  • mhd_tests:

    • Alfven: a linearized MHD wave test problem from [32] and [7].

    • BrioWu: the Brio Wu shock tube problem as described in [22]. This is a standard test problem used in many MHD code papers (e.g. [65]).

    • DaiWoodward: a shock tube problem described in [4]

    • FastRarefaction: a shock tube problem dominated by kinetic energy, as described in [7]

    • MagnetosonicWaves: the fast and slow magnetosonic wave problem from [32]

    • OrszagTang: a two-dimensional magnetized vortex problem, following [65]

    • RT: a magnetized Rayleigh-Taylor instability problem

    • species: a simple test problem to ensure that species are accurately advected.

  • radiation_tests:

    • Rad2Tshock: This sets up a radiating shock that can be compared to a semi-analytic solution described in [53].

    • RadFront: This is the optically-thin streaming of a radiation front problem demonstrated originally in Castro in [72].

    • RadShestakovBolstad: This is a linear multigroup diffusion test problem first described by [11] and demonstrated in Castro in [73].

    • RadSourceTest: Test the implementation of the source terms in the gray radiation solver. This does the “relaxation to thermal equilibrium” test as described in [66] (originally described in [69]).

    • RadSphere: This is a multigroup radiating sphere test problem with an analytic solution, described in [41] and [66] and shown in Castro in [73].

    • RadSuOlson: This is a non-equlibrium Marshak wave test described in [3] and shown in Castro in [72].

    • RadSuOlsonMG: This is a multigroup version of RadSuOlson described in [12] and shown in Castro in [73].

    • RadThermalWave: A thermal wave test adapted from [44] and shown in Castro in [72].

  • reacting_tests:

    • bubble_convergence: a reacting bubble problem designed for measuring the convergence of the reactive hydro algorithms in Castro. This was used in [76].

    • reacting_bubble: A reacting bubble in a stratified white dwarf atmosphere. This problem was featured in the Maestro reaction paper [20].

    • reacting_convergence: a simple reacting hydrodynamics problem for measuring convergence, used in [76] and [16]

  • science:

    The problems in the science directory are science problems that have appeared in papers (or will shortly). Many of these are being actively used and are shared here for reproducibility.

    • Detonation: this sets up a 1-d detonation that propagates through the domain.

    • flame: this sets up a 1-d deflagration that propagates through the domain. This setup was used for the testing in [34].

    • flame_wave: this is a model of a flame propagating across a neutron star as a model for an X-ray burst. This was presented in [34] and [5].

    • nova: this models convection at the base of an accreted layer on a white dwarf as a model of a nova.

    • planet: this is the problem setup from [61] that models shear and turbulence in a hot Jupiter atmosphere.

    • subchandra: a model of sub-Chandra Type Ia supernova that initializes a hot spot in a helium layer on a low mass carbon-oxygen white dwarf.

    • wdmerger: a problem setup for modeling white dwarf mergers. This was used in [50].

    • xrb_mixed: a compressible version of the X-ray burst convection problem from [77].

  • unit_tests:

    • diffusion_test: a test of thermal diffusion (without hydro). This was used to demonstrate convergence in both [76] and [34].

    • particles_test: a test of passive particles.