CFD Solvers

pimpleFoam is a transient solver for incompressible flows using the PIMPLE algorithm (a combination of PISO and SIMPLE). SIMD Agent selects it for unsteady, single-phase, incompressible problems without heat transfer.

When the agent selects this solver

• Single-phase, incompressible fluid
• No heat transfer required
• Transient solution needed (unsteady, time-varying, oscillating, pulsating)
• Mach number well below 0.3

Typical applications include vortex shedding behind bluff bodies, pulsating flows in pipelines, moving mesh problems, and any unsteady industrial flow simulation.

Required files

Pressure field

Like simpleFoam, pimpleFoam uses kinematic pressure [0 2 -2 0 0 0 0]. It is strictly incompressible, no density field, no compressible divergence terms.

Time control

Unlike steady-state solvers, endTime and deltaT are in physical seconds, not iteration counts.

// system/controlDict
application  pimpleFoam;
startTime    0;
endTime      10;      // physical seconds
deltaT       0.001;   // physical time step
adjustTimeStep yes;
maxCo        0.9;

PIMPLE settings

The PIMPLE block in fvSolution requires three corrector settings. These control the pressure-velocity coupling iterations within each time step.

PIMPLE
{
    nOuterCorrectors    2;
    nCorrectors         1;
    nNonOrthogonalCorrectors 1;
}

Laminar mode

For laminar flows, set simulationType laminar; in turbulenceProperties and omit all turbulence fields (k, omega, epsilon, nut) and their divergence scheme entries.

Files never generated

pimpleFoam is strictly incompressible. The agent will never generate:

• 0/T, 0/rho, no energy or density fields
• constant/thermophysicalProperties, no thermodynamics
• constant/g, no buoyancy
• 0/alphat, no thermal diffusivity

The divergence schemes must not include compressible terms like div(phid,p), div(phi,K), or div(phi,Ekp).