6

Next: Zero Gradient Family of Up: Fixed Static Pressure Family Previous: fixedMeanValue Static Pressure Boundary   Contents   Index

outletVent Boundary Condition

outletVent boundary condition computes and prescribes special static pressure value at the outlet (goes locally, face by face). The formula for static pressure is following:
$\displaystyle \color{white} p_{s_{out}}^{eachFace} = p_{0} + resistance \cdot \frac{1}{2} \rho \cdot \Vert U \Vert^2$ (2.1)
where $ \color{white} p_{0}$ is the reference static pressure, resistance is the resistance factor, $ \color{white} \rho$ is the density and $ \color{white} U$ is the velocity magnitude p:
 boundaryField
 {
 ".*_outlet"
    {
        type            outletVent;
        resistance      0.0;
        p0              uniform 100000.0;
        relax           0.1;
        pMax            150000.0;
        value           $internalField;
    }
 }
The physical meaning of outletVent boundary condition can be understood as a valve at the outlet that can be gradually opened and closed by increasing and decreasing the resistance factor. relax is relaxation factor of the static pressure to dump oscillations. pMax is maximum allowed value of the static pressure to dump oscillations .