gh-k-dense-ai-claude-scientific-skills-scientific-skills/skills/fluidsim/references/solvers.md

FluidSim Solvers

FluidSim provides multiple solvers for different fluid dynamics equations. All solvers work on periodic domains using pseudospectral methods with FFT.

Available Solvers

2D Incompressible Navier-Stokes

Solver key: ns2d

Import:

from fluidsim.solvers.ns2d.solver import Simul
# or dynamically
Simul = fluidsim.import_simul_class_from_key("ns2d")

Use for: 2D turbulence studies, vortex dynamics, fundamental fluid flow simulations

Key features: Energy and enstrophy cascades, vorticity dynamics

3D Incompressible Navier-Stokes

Solver key: ns3d

Import:

from fluidsim.solvers.ns3d.solver import Simul

Use for: 3D turbulence, realistic fluid flow simulations, high-resolution DNS

Key features: Full 3D turbulence dynamics, parallel computing support

Stratified Flows (2D/3D)

Solver keys: ns2d.strat, ns3d.strat

Import:

from fluidsim.solvers.ns2d.strat.solver import Simul  # 2D
from fluidsim.solvers.ns3d.strat.solver import Simul  # 3D

Use for: Oceanic and atmospheric flows, density-driven flows

Key features: Boussinesq approximation, buoyancy effects, constant Brunt-Väisälä frequency

Parameters: Set stratification via params.N (Brunt-Väisälä frequency)

Shallow Water Equations

Solver key: sw1l (one-layer)

Import:

from fluidsim.solvers.sw1l.solver import Simul

Use for: Geophysical flows, tsunami modeling, rotating flows

Key features: Rotating frame support, geostrophic balance

Parameters: Set rotation via params.f (Coriolis parameter)

Föppl-von Kármán Equations

Solver key: fvk (elastic plate equations)

Import:

from fluidsim.solvers.fvk.solver import Simul

Use for: Elastic plate dynamics, fluid-structure interaction studies

Solver Selection Guide

Choose a solver based on the physical problem:

1. 2D turbulence, quick testing: Use ns2d
2. 3D flows, realistic simulations: Use ns3d
3. Density-stratified flows: Use ns2d.strat or ns3d.strat
4. Geophysical flows, rotating systems: Use sw1l
5. Elastic plates: Use fvk

Modified Versions

Many solvers have modified versions with additional physics:

• Forcing terms
• Different boundary conditions
• Additional scalar fields

Check fluidsim.solvers module for complete list.