Case schema · Gyre

CaseSpec — Complete, serialisable description of a steady flow analysis.

field	type	default	description
`name`	string	`case`	(max length 80, pattern ^[A-Za-z0-9_.-]+$)
`description`	string
`mesh`	MeshSpec	`required`
`flow`	FlowSpec
`discretization`	DiscretizationSpec
`solver`	SolverSpec
`reference`	ReferenceSpec

MeshSpec — Built-in mesh generator and its parameters, or a mesh file (generator: file).

field	type	default	description
`generator`	`airfoil_omesh` \| `annulus` \| `bump_channel` \| `flat_plate` \| `sphere_shell` \| `box` \| `file`	`required`	Name of the built-in mesh generator, or ‘file’ for an external mesh (params: path, optional scale; Gmsh .msh 2.2/4.1 ASCII or Gyre .npz).
`params`	mapping		Keyword arguments of the generator (e.g. n_surf, n_radial, r_far, code); unknown, missing or mistyped arguments are validation errors.
`geometry_order`	integer	`4`	Polynomial degree of the curved elements (generators only: a mesh file carries its own degree). (≥ 1, ≤ 8)

FlowSpec — Free-stream / reference flow conditions (all differentiable inputs).

field	type	default	description
`mach`	number	`0.5`	Free-stream Mach number. (> 0.0, < 5.0)
`alpha_deg`	number	`0.0`	Angle of attack in degrees. (≥ -90.0, ≤ 90.0)
`beta_deg`	number	`0.0`	Sideslip angle in degrees (3-D only; ignored in 2-D). Free-stream direction: (cos a cos b, sin a cos b, sin b). (≥ -90.0, ≤ 90.0)
`reynolds`	number or null	`None`	Reynolds number (unit reference length); null means inviscid.
`prandtl`	number	`0.72`	(> 0.0)
`gamma`	number	`1.4`	(> 1.0)
`turbulence`	`none` \| `sa`	`none`	Turbulence closure: ‘none’ (laminar or inviscid) or ‘sa’ (negative Spalart-Allmaras RANS model; requires reynolds).
`extra`	mapping		Additional boundary data: p_back, pt_in, tt_in, t_wall, suth; with turbulence ‘sa’ also chi_inf (free-stream nu_tilde/nu, default 3) and prt (turbulent Prandtl number, default 0.9).

DiscretizationSpec — Spatial discretization.

field	type	default	description
`order`	integer	`2`	Solution polynomial degree p (accuracy p+1); viscous cases need p >= 1. (≥ 0, ≤ 8)
`two_point_flux`	`ranocha` \| `chandrashekar` \| `kennedy_gruber` \| `central`	`ranocha`
`surface_flux`	`roe` \| `es_roe` \| `hllc` \| `llf`	`roe`	Interface flux: ‘roe’ and ‘hllc’ are the classical solvers; ‘es_roe’ (matrix dissipation in entropy variables) and ‘llf’ (scalar dissipation) are entropy stable with an entropy-conservative two_point_flux.
`shock_capturing`	boolean	`False`	Sensor-based artificial viscosity for flows with shocks.
`av_coef`	number	`1.0`	Artificial-viscosity scale (multiples of h/p * (\|u\|+c)). (> 0.0, ≤ 10.0)
`boundaries`	mapping		Boundary group -> condition; defaults are chosen per generator.

SolverSpec — Nonlinear and linear solver controls.

field	type	default	description
`levels`	list of integer or `auto` \| `single`	`auto`	p-multigrid degrees fine->coarse, ‘auto’ (p, p//2, …, 0) or ‘single’.
`tol_rel`	number	`1e-10`	(> 0.0, < 1.0)
`max_steps`	integer	`150`	(≥ 1, ≤ 5000)
`cfl0`	number	`5.0`	(> 0.0)
`cfl_growth`	number	`10.0`	(≥ 1.0)
`cfl_shrink`	number	`1.0`	Factor applied to the CFL number after a step that the line search shortened to a quarter or less (1: hold the CFL). (> 0.0, ≤ 1.0)
`lin_tol`	number	`0.01`	(> 0.0, < 1.0)
`krylov_dim`	integer	`40`	(≥ 5, ≤ 400)
`restarts`	integer	`2`	(≥ 1, ≤ 50)
`smoother`	`jacobi` \| `gmres` \| `line`	`jacobi`	Smoother of the p-multigrid levels: damped block Jacobi, block-Jacobi GMRES, or line Jacobi (block-tridiagonal solves along lines of strongly coupled elements of an anisotropic mesh; block Jacobi where the mesh has none).
`precond_lag`	integer	`1`	Assemble the blocks of the smoother every this many nonlinear steps (1: every step). In between, the last blocks are reused. (≥ 1, ≤ 50)
`precond_precision`	`double` \| `single`	`double`	Precision in which the blocks of the smoother are assembled, stored and applied. ‘single’ halves their memory, which is what bounds the size of a 3-D problem on one device; the residual, its Jacobian products, the Krylov vectors and the inverses stay in double precision, so the solution is unchanged and only the iteration count can differ.

ReferenceSpec — Reference quantities of the force and moment coefficients.

field	type	default	description
`area`	number or null	`None`	Reference area (length in 2-D). Default: 1 in 2-D, the span of a spanwise-extruded generator mesh in 3-D, the frontal area of the body of a sphere_shell mesh.
`length`	number	`1.0`	Reference length of the moment coefficient. (> 0.0)
`moment_center`	list of number		Point about which the moment is taken.
`groups`	list of string or null	`None`	Wall boundary groups over which the force, moment and heat-flux coefficients are integrated (the loads of one component). Default: every wall group of the mesh. The nodal load field f_surface and the surface displacement x_surface always cover all walls.
`components`	mapping or null	`None`	Named components of the walls, each a list of wall boundary groups. Every force, moment and heat-flux coefficient is then also an output per component, named _ (cd_wing, cl_tail, …), from the same solve and with its own derivatives. Names are letters and digits.

The table is generated from the model, so a field has a description here only if the model declares one. The meaning of the remaining fields — the flux choices, the solver controls, flow.prandtl, flow.gamma and the keys of flow.extra — is given under Cases, and the generator parameters under Mesh generators.

Presets#

preset	description	elements	DOF	model
`naca0012_euler`	Inviscid subsonic flow over a NACA 0012 aerofoil (M=0.5, alpha=2 deg).	256	9,216	Euler, 2-D
`naca0012_laminar`	Laminar flow over a NACA 0012 aerofoil (M=0.5, alpha=1 deg, Re=5000).	480	17,280	Navier–Stokes, 2-D
`naca2412_euler`	Inviscid flow over a cambered NACA 2412 aerofoil (M=0.4, alpha=1 deg).	256	9,216	Euler, 2-D
`naca0012_transonic`	Transonic inviscid flow over a NACA 0012 aerofoil (M=0.8, alpha=1.25 deg) with sensor-based shock capturing.	1024	36,864	Euler, 2-D
`naca0012_euler_3d`	Spanwise-periodic 3-D extrusion of the inviscid NACA 0012 case (hexahedra): exercises the 3-D operators, solver and adjoint; coefficients per unit span.	192	25,920	Euler, 3-D
`cylinder_re40`	Steady separated laminar flow past a circular cylinder (Re_D=40, M=0.2).	240	15,360	Navier–Stokes, 2-D
`sphere_euler`	Inviscid subsonic flow past a sphere (M=0.2) on a cubed-sphere mesh of curved hexahedra: a genuinely 3-D, unstructured-topology case whose exact solution has no drag and no entropy rise.	216	29,160	Euler, 3-D
`sphere_re100`	Steady laminar flow past a sphere (Re_D=100, M=0.2): 3-D Navier-Stokes with a closed recirculation bubble; drag referred to the frontal area.	576	77,760	Navier–Stokes, 3-D
`flat_plate_sa`	Turbulent flat plate at zero pressure gradient (M=0.2, Re=5e6 per unit length) with the Spalart-Allmaras model: the NASA Turbulence Modeling Resource verification case on a coarse wall-resolved mesh.	150	6,750	Navier–Stokes, 2-D
`bump_euler`	Inviscid subsonic channel flow over a smooth Gaussian bump (M=0.5): the exact solution is isentropic, so the entropy error measures accuracy.	48	3,072	Euler, 2-D