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Boundary and Initial Conditions of fan-noHousing-compressible

Following table shows recommended model of boundary conditions for computed variables:

The shortcuts from the table above have following meaning:


  • pTot – totalPressure prescribes fixed total pressure
  • pDIV – pressureDirectedInletVelocity prescribes velocity angles at the inlet, but the velocity magnitude is computed from total pressure – static pressure difference
  • oV – outletVent prescribes special static pressure to imitate valve
  • fRV – flowRateVelocity prescribes fixed flow rate
  • hTP – hydrostaticTotalPressure sets the total pressure at a patch including linear distribution of hydrostatic pressure in the gravity direction with respect to a reference value pInletCenter (e.g. img277) in the center of a patch.
  • tIKEI – turbulentIntensityKineticEnergyInlet, intensity = 0.05, corresponds to turbulence intensity 5%
  • fV – fixedValue, e.g. velocity at the wall (0 0 0), or omega at inlet
  • fMV – fixedMeanValue, is the same as fixed value, e.g. for pressure, but certain freedom is allowed to keep the variable average equal to meanValue
  • zG – zeroGradient, the flux is zero in direction perpendicular to the surface
  • kWF – kqRWallFunction is a standard wall function for k for incompressible flow
  • oWF – omegaWallFunction is a standard wall function for omega for incompressible flow
  • mI – mixingInterface, averaged quantity is mapped from the neighbour patch
  • iO – inletOutlet is by default zeroGradient, but changes to fixedValue when velocity vector direction points inside the computational domain (backward flow)

See also Chapter (crossref), where the boundary conditions are described.

NOTE: In this particular tutorial case the surface model is simplified and the spiral is closed at the end of the wheel (no full housing is considered). The closing wall might have a special boundary condition for velocity. Either standard fixed wall (fixedValue), or rotatingWallVelocity.