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 :cite:`colgwhite`. 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 :cite:`Evrard1988`. This implementation of the test comes from section 9.1 of :cite:`springel:2010`. * ``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 :math:`|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 :cite:`maestro:II`. * ``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 :cite:`katz:2016`. * ``hydro_tests``: * ``acoustic_pulse``: The acoustic pulse problem from :cite:`mccorquodalecolella` used to measure convergence of pure hydrodynamics problems (as used for Castro in :cite:`castro-sdc`). * ``acoustic_pulse_general``: a general equation of state version of ``acoustic_pulse`` used for measuring convergence in :cite:`castro-sdc`. * ``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 :math:`\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 :cite:`quirk1997`. 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 :cite:`castro_I`. * ``Sod``: A one-dimensional shock tube setup, including the classic Sod problem. This setup was used in the original Castro paper :cite:`castro_I`. * ``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 :cite:`zingalekatz`. * ``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 :cite:`crockett:2005` and :cite:`miniati_martin`. * ``BrioWu``: the Brio Wu shock tube problem as described in :cite:`briowu`. This is a standard test problem used in many MHD code papers (e.g. :cite:`athena`). * ``DaiWoodward``: a shock tube problem described in :cite:`Dai_1998` * ``FastRarefaction``: a shock tube problem dominated by kinetic energy, as described in :cite:`miniati_martin` * ``MagnetosonicWaves``: the fast and slow magnetosonic wave problem from :cite:`crockett:2005` * ``OrszagTang``: a two-dimensional magnetized vortex problem, following :cite:`athena` * ``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 :cite:`lowrieedwards`. * ``RadFront``: This is the optically-thin streaming of a radiation front problem demonstrated originally in Castro in :cite:`CastroII`. * ``RadShestakovBolstad``: This is a linear multigroup diffusion test problem first described by :cite:`SHESTAKOV2005` and demonstrated in Castro in :cite:`CastroIII`. * ``RadSourceTest``: Test the implementation of the source terms in the gray radiation solver. This does the "relaxation to thermal equilibrium" test as described in :cite:`swestymyra:2009` (originally described in :cite:`turnerstone2001`). * ``RadSphere``: This is a multigroup radiating sphere test problem with an analytic solution, described in :cite:`graziani:2008` and :cite:`swestymyra:2009` and shown in Castro in :cite:`CastroIII`. * ``RadSuOlson``: This is a non-equlibrium Marshak wave test described in :cite:`suolson:1996` and shown in Castro in :cite:`CastroII`. * ``RadSuOlsonMG``: This is a multigroup version of ``RadSuOlson`` described in :cite:`suolson:1999` and shown in Castro in :cite:`CastroIII`. * ``RadThermalWave``: A thermal wave test adapted from :cite:`howellgreenough:2003` and shown in Castro in :cite:`CastroII`. * ``reacting_tests``: * ``bubble_convergence``: a reacting bubble problem designed for measuring the convergence of the reactive hydro algorithms in Castro. This was used in :cite:`castro-sdc`. * ``reacting_bubble``: A reacting bubble in a stratified white dwarf atmosphere. This problem was featured in the Maestro reaction paper :cite:`maestro:III`. * ``reacting_convergence``: a simple reacting hydrodynamics problem for measuring convergence, used in :cite:`castro-sdc` and :cite:`strang_rnaas` * ``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 :cite:`eiden:2020`. * ``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 :cite:`eiden:2020` and :cite:`harpole2021dynamics`. * ``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 :cite:`ryu:2018` 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 :cite:`katz:2016`. * ``xrb_mixed``: a compressible version of the X-ray burst convection problem from :cite:`zingale:2015`. * ``unit_tests``: * ``diffusion_test``: a test of thermal diffusion (without hydro). This was used to demonstrate convergence in both :cite:`castro-sdc` and :cite:`eiden:2020`. * ``particles_test``: a test of passive particles.