Solver Configuration

Status: Skeleton — content to be filled as the JSON schema stabilizes.

DNDSR solvers are controlled through JSON configuration files. The C++ solver reads the JSON at startup; the Python EulerP module can also construct a config programmatically.

TODO: Add a complete JSON Schema or annotated example for each solver variant (euler, eulerSA, euler2EQ, euler3D, …).

File Layout

A typical solver config lives under cases/<solver>/<case_name>.json:

{
  "meshFile": "path/to/mesh.cgns",
  "meshElevation": "",
  "meshDirectBisect": 0,
  "outputDirectory": "./output",
  "nTimeSteps": 1000,
  "dt": 1e-3,
  ...
}

TODO: Document the top-level keys common to all solvers.

Sections

Mesh Settings

Key

Type

Default

Description

meshFile

string

required

Path to CGNS or H5 mesh file

meshElevation

string

""

"" or "O2" for quadratic elevation

meshDirectBisect

int

0

Number of bisection levels

periodicTranslation

array[3]

—

Periodic translation vector

periodicTolerance

float

1e-9

Tolerance for periodic deduplication

TODO: Complete all mesh-related keys.

Physics Settings

TODO: Document keys for:

  • Equation set (NS, NS_SA, NS_2EQ, …)

  • Gas model (IdealGas, …)

  • Reynolds number, Mach number, reference conditions

  • Turbulence model parameters (SA, k-omega SST, etc.)

  • Rotation / source terms

Numerical Settings

TODO: Document keys for:

  • Spatial order (P1, P2, P3)

  • Time integrator (SSPRK3, BDF2, ESDIRK4, HM3, …)

  • CFL number and adaptivity

  • Limiter settings

  • Jacobian update frequency

  • Linear solver settings (GMRES restart, tolerance, preconditioner)

Boundary Conditions

Boundary conditions are specified as a list of objects, each matching a zone name from the CGNS file:

{
  "boundaryConditions": [
    {
      "name": "wall",
      "type": "Wall",
      "temperature": "adiabatic"
    },
    {
      "name": "farfield",
      "type": "Riemann",
      "state": "freestream"
    }
  ]
}

TODO: List all supported BC types and their parameters.

  • Wall (no-slip, adiabatic, isothermal)

  • Inlet (total pressure/temperature, mass flow)

  • Outlet (static pressure, extrapolation)

  • Symmetry

  • Periodic

  • Riemann (far-field)

Output Settings

TODO: Document keys for:

  • VTK / Tecplot output frequency and fields

  • Restart checkpointing

  • Console logging level and frequency

  • Probe / slice / force extraction

Solver-Specific Notes

Euler (Inviscid)

TODO: Keys unique to inviscid Euler solver.

EulerSA (Spalart-Allmaras)

TODO: SA-specific parameters (CB1, CB2, sigma, …).

Euler2EQ (k-omega / SST)

TODO: Two-equation model-specific parameters.

Complete Example

TODO: Provide a fully commented example config for a standard test case (e.g. NACA0012, periodic vortex, or cylinder).

See Also