Description🔗

The swirlFanVelocity is a boundary condition that provides a jump condition for velocity across a cyclic pressure jump condition and applies a transformation to the velocity.

The velocity jump is specified with a swirl component as follows:

\[u_{tan} = \frac{\Delta_P}{r_{eff} f_{eff} \omega_{rpm} \frac{\pi}{30}}\]

where:

Alternatively an inner and outer radii can be used instead of \(r_{eff}\). The \(u_{tan}\) is as follows for \(r > r_{inner}\) and \(r < r_{outer}\):

\[u_{tan} = \frac{\Delta_P}{r f_{eff} \frac{\omega_{rpm}}{\pi 30}}\]

with \(r = x_{f} - x_{origin}\), and \(f\) is the face center.

The radial velocity is zero in the this model.

Usage🔗

The condition requires entries in both the boundary and field files.

Boundary file🔗

<patchName>
{
    type            patch;
    ...
}

Field file🔗

<patchName>
{
    // Mandatory entries
    type            swirlFanVelocity;
    rpm             <Function1<scalar>>;

    // Optional entries
    phi             <word>;
    p               <word>;
    rho             <word>;
    origin          <vector>;
    fanEff          <scalar>;
    rEff            <scalar>;
    rInner          <scalar>;
    rOuter          <scalar>;
    useRealRadius   <bool>;

    // Inherited entries
    patchType       cyclic;
    ...
}

where:

The inherited entries are elaborated in:

• Foam::fixedJumpFvPatchField

• Foam::Function1

• Negative rpm will reverse the input tangential direction.
• This boundary condition needs to be used with a pressure-jump (e.g. fan) condition with a non-zero dp, otherwise no swirl will be applied (dp=0).
• Please ensure physical and complementary set-ups for the pressure-jump and swirlFanVelocity boundary conditions.

Further information🔗

Tutorial:

• N/A

Source code:

• $FOAM_SRC/finiteVolume/fields/fvPatchFields/derived/swirlFanVelocity

API:

• Foam::swirlFanVelocityFvPatchField

History:

• Introduced in version v1806