Problem Definition

The following inputs must be preceded by “amr.”

	Description	Type	Default
n_cell	Number of cells at level 0 in each coordinate direction	Int Int Int	None
max_level	Maximum level of refinement allowed (0 when single-level)	Int	None

The following inputs must be preceded by “geometry.”

	Description	Type	Default
coord_sys	0 for Cartesian	Int	0
is_periodic	1 for true, 0 for false (one value for each coordinate direction)	Ints	0 0 0
prob_lo	Low corner of physical domain (physical not index space)	Reals	None
prob_hi	High corner of physical domain (physical not index space)	Reals	None

The following inputs must be preceded by “incflo.”

	Description	Type	Default
geometry	Which type of EB geometry are we using?	String
gravity	Gravity vector (e.g., incflo.gravity = -9.81 0.0 0.0)	Reals	(0, 0, 0)
delp	Pressure drop (Pa)	Real	(0, 0, 0)

Setting basic boundary conditions can be specified by inputs preceded by “xlo”, “xhi”, “ylo”, “yhi”, “zlo”, and “zhi”

	Description	Type	Default
type	Used to define boundary type. Available options include: ‘pi’ or ‘pressure_inflow’ ‘po’ or ‘pressure_outflow’ ‘mi’ or ‘mass_inflow’ ‘nsw’ or ‘no_slip_wall’ ‘mixed’	String	None
pressure	Sets boundary pressure for pressure inflows, outflows and mass inflows	Real	None
velocity	Sets boundary velocity for mass inflows	Reals	(0, 0, 0)
density	Sets boundary density for mass inflows	Real	1.0
tracer	Sets boundary tracer for mass inflows	Real	0.0

The ‘mixed’ boundary type allows for inflow and outflow on the same domain face. The implementation requires that there is EB separating the inflow and outflow regions, and only currently treats constant viscosity (i.e. requires the inputs file contains incflo.use_tensor_solve = false). It does allow for non-constant scalar diffusivity. To create a new problem setup with mixed BCs, one must additionally specify the Dirchlet and Neumann areas in prob/prob_bc.cpp In this file there are functions to set the needed BC info for the diffusion solver, the MAC projection, and with the same function, the nodal projection and advection. Comments in the code provide a detailed explaination for each instance. For addditional details on mixed BCs, also see AMReX-Hydro’s documentation (Boundary conditions).