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,
...     numerical_dissipation_factor=0.01,
...     linear_solver=LinearSolver(max_iterations=50),
...     low_mach_preconditioner=True,
... )

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

equation_evaluation_frequency: int

Frequency at which to solve the equation.

Default:

1

linear_solver: LinearSolver

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

numerical_dissipation_factor: float

A factor in the range [0.01, 1.0] which exponentially reduces the dissipation of the numerical flux. The recommended starting value for most low-dissipation runs is 0.2.

Default:

1

limit_velocity: bool

Limiter for velocity

Default:

False

limit_pressure_density: bool

Limiter for pressure and density.

Default:

False

low_mach_preconditioner: bool

Use preconditioning for accelerating low Mach number flows.

Default:

False

low_mach_preconditioner_threshold: float, optional

For flow regions with Mach numbers smaller than threshold, the input Mach number to the preconditioner is assumed to be the threshold value if it is smaller than the threshold. The default value for the threshold is the freestream Mach number.

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

Additional Constructors

classmethod from_file(filename)

Loads a Flow360BaseModel from .json, or .yaml file.

Parameters:

filename (str) – Full path to the .yaml or .json file to load the Flow360BaseModel from.

Returns:

An instance of the component class calling load.

Return type:

Flow360BaseModel

Example

>>> params = Flow360BaseModel.from_file(filename='folder/sim.json') 

Methods

help(methods=False)

Prints message describing the fields and methods of a Flow360BaseModel.

Parameters:

methods (bool = False) – Whether to also print out information about object’s methods.

Return type:

None

Example

>>> params.help(methods=True) 

to_file(filename, **kwargs)

Exports Flow360BaseModel instance to .json or .yaml file

Parameters:

filename (str) – Full path to the .json or .yaml or file to save the Flow360BaseModel to.

Return type:

None

Example

>>> params.to_file(filename='folder/flow360.json')