NavierStokesSolver

class NavierStokesSolver

Bases: GenericSolverSettings

NavierStokesSolver class for setting up the compressible Navier-Stokes solver. For more information on setting up the numerical parameters for the Navier-Stokes solver, refer to Navier-Stokes solver knowledge base.

Example

>>> fl.NavierStokesSolver(
...     absolute_tolerance=1e-10,
...     riemann_solver=fl.RoeFlux(numerical_dissipation_factor=0.01, low_mach_preconditioner=True),
...     linear_solver=LinearSolver(max_iterations=50),
... )

Attributes

absolute_tolerance: float

Tolerance for the NS residual, below which the solver goes to the next physical step.

Default:

1e-10

relative_tolerance: float

Tolerance to the relative residual, below which the solver goes to the next physical step. Relative residual is defined as the ratio of the current pseudoStep’s residual to the maximum residual present in the first 10 pseudoSteps within the current physicalStep. NOTE: relativeTolerance is ignored in steady simulations and only absoluteTolerance is used as the convergence criterion.

Default:

0

order_of_accuracy: Literal[1, 2]

Order of accuracy in space.

Default:

2

equation_evaluation_frequency: int

Frequency at which to solve the equation.

Default:

1

linear_solver: LinearSolver | KrylovLinearSolver

Linear solver configuration. Use KrylovLinearSolver for Newton-Krylov.

Default:

LinearSolver()

CFL_multiplier: float

Factor to the CFL definitions defined in the Time Stepping section.

Default:

1.0

kappa_MUSCL: float

Kappa for the MUSCL scheme, range from [-1, 1], with 1 being unstable. The default value of -1 leads to a 2nd order upwind scheme and is the most stable. A value of 0.33 leads to a blended upwind/central scheme and is recommended for low subsonic flows leading to reduced dissipation.

Default:

-1

limit_velocity: bool

Limiter for velocity

Default:

False

limit_pressure_density: bool

Limiter for pressure and density.

Default:

False

type_name: Literal['Compressible', 'CompressibleIsentropic']

The type of Navier-Stokes equations to solve. The default is the compressible conservation laws. CompressibleIsentropic is recommended for low mach number applications to speed up the solver. It will apply mass and momentum conservation along with the isentropic assumption for low-speed flow.CompressibleIsentropic is applied automatically for LiquidOperatingCondition regardless of the value of this field.

Default:

'Compressible'

line_search: LineSearch, optional

Line search parameters for the Newton-Krylov solver. Only valid when linear_solver is a KrylovLinearSolver.

Default:

None

update_jacobian_frequency: int

Frequency at which the jacobian is updated.

Default:

4

max_force_jac_update_physical_steps: int

When physical step is less than this value, the jacobian matrix is updated every pseudo step.

Default:

0

riemann_solver: RoeFlux | SLAU2Flux

Riemann solver used for the inviscid flux. Defaults to RoeFlux.

Default:

RoeFlux()