Pressure-velocity systems

Incompressible

Inlet Outlet Stability
Physics OpenFOAM Physics OpenFOAM
Volume flow rate flowRateInletVelocity Static pressure fixedValue Excellent
Total pressure totalPressure Total pressure totalPressure Very good
Total pressure totalPressure Static pressure fixedValue Good
Static pressure fixedValue Static pressure fixedValue Poor

Compressible

Inlet Outlet Stability
Physics OpenFOAM Physics OpenFOAM
Mass flow rate flowRateInletVelocity Static pressure fixedValue Excellent
Total pressure totalPressure Total pressure totalPressure Very good
Total pressure totalPressure Static pressure fixedValue Good
Static pressure fixedValue Static pressure fixedValue Poor

Return flow options

Type Condition Stability
Outflow zeroGradient Unstable if flow reverses
Blocked inletOutlet Good, but unphysical
Return flow I pressureInletOutlet Good
Return flow II totalPressure Very good

Heat transfer

Walls

Type Condition
Adiabatic zeroGradient
Fixed temperature fixedValue
Fixed heat flux fixedGradient

Mesh motion

Walls

Type Condition
Moving wall movingWallVelocity