GASPv4 Boundary Condition Information

Fixed at Q

• Sets all the primitive variables using Q source.

1st Order Extrapolation

• Extrapolates all primitive variables.

2nd Order Extrapolation

• Extrapolates all primitive variables.

Riemann Subsonic In/Outflow

• If flow is entering domain (Inflow):
  • Rieman invariants used based on flow direction.
  • Non-equilibrium energy set using Q source.
  • K-Epsilon is set using Q source.
  • K-Omega is extrapolated.
  • Spalart-Allmaras is set to zero.
• If flow is leaving domain (Outflow):
  • Rieman invariants used based on flow direction.
  • Non-equilibrium energy extrapolated.
  • Turbulence variables are extrapolated.

Fixed Mass Flow Subsonic In

• Mass flow is taken from Q source and used to set the flow variables.
• Total temperature is held constant.
• Turbulence models are set as:
  • K-Epsilon is set to Q source.
  • K-Omega is extrapolated.
  • Spalart-Allmaras is set to zero.

PO-TO Subsonic Inflow

• Total pressure and total temperature are held constant, as specified by Q source.
• Turbulence models are set as:
  • K-Epsilon is set to Q source.
  • K-Omega is extrapolated.
  • Spalart-Allmaras is set to zero.

PBack Subsonic Outflow

• Primitive variables are extrapolated except for pressure, which is set according to Q source.

Subsonic PO-To Inflow/Outflow

• Depending on flow direction, either PO-TO Subsonic Inflow or PBack Subsonic Outflow is enforced.

Inflow-Outflow Relax P

• If flow is into domain, flow variables are set to Q source except for pressure, which is extrapolated.
• If flow is out of domain, PBack Subsonic OutFlow is enforced.
• Turbulence models are set as:
  • K-Epsilon is set to Q source for inflow and extrapolated for outflow.
  • K-Omega is extrapolated.
  • Spalart-Allmaras is set to zero for inflow, and extrapolated for outflow.

Forced Outflow

• Enforces the 1st Order Extrapolation boundary condition and forces the velocity to exit the domain (prevents backflow into domain).

Tangency

• Intended for solid wall inviscid surfaces.
• Turbulence variables are extrapolated.

Tangency: Split

• Same as Tangency, except it applies the boundary condition at the ghost cell instead of at the boundary face.

No-Slip Adiabatic

• Viscous solid wall boundary condition which assumes no heat transfer at the wall.
• Turbulence models are set as:
  • K-Epsilon is set according to which type is selected (i.e. Chien sets k and epsilon to 0, while all others set k to 0 and extrapolates epsilon).
  • K-Omega is set according to roughness parameter.
  • Spalart-Allmaras is set to zero.

No-Slip Adiabatic: Split

• Same as No-Slip Adiabatic, except it applies the boundary condition at the ghost cell instead of at the boundary face.

No-Slip T=Twall

• Viscous solid wall boundary condition which sets the wall temperature according to Q source.
• Turbulence models are set as:
  • K-Epsilon is set according to which type is selected (i.e. Chien sets k and epsilon to 0, while all others set k to 0 and extrapolates epsilon).
  • K-Omega is set according to roughness parameter.
  • Spalart-Allmaras is set to zero.

No-Slip T=Twall: Split

• Same as No-Slip T=Twall, except it applies the boundary condition at the ghost cell instead of at the boundary face.

No-Slip COIL Catalytic

• COIL = Chemical Oxygen-Iodine Lasers
• No slip, fixed wall temperature, zero pressure gradient. Valid only for the 10 species COIL chemistry model in combination with the effective diffusion model.
• Turbulence parameters set as in No-Slip Adiabatic condition.

Air Catalytic T=Twall: Partial

• Air catalytic wall boundary condition. Radiation not included. Wall temperature set by q source.
• Valid only for 5, 7, and 11 species air chemistry models
• Turbulence parameters set as in No-Slip T=Twall condition.

Air Catalytic Adiabatic: Partial

• Air catalytic wall boundary condition. Radiative equilibrium energy balance (adiabatic wall).
• Valid only for 5, 7, and 11 species air chemistry models
• Turbulence parameters set as in No-Slip Adiabatic condition.

Air Catalytic T=Twall: Full

• Air catalytic wall boundary condition. Fully catalytic. Wall temperature set by q source.
• Valid only for 5, 7, and 11 species air chemistry models Forces composition to 0.767 N2 and 0.233 O2 at wall.
• Turbulence parameters set as in No-Slip T=Twall condition.

X-Axis Axi-symmetric

• For axi-symmetric grids where the singular line is the x-axis.

Y-Axis Axi-symmetric

• For axi-symmetric grids where the singular line is the y-axis.

Z-Axis Axi-symmetric

• For axi-symmetric grids where the singular line is the z-axis.

Symmetry Plane

• Assumes the flow is symmetric across the boundary face.

Y-Z Symmetry Plane

• Assumes the flow is symmetric across the boundary face and that the entire surface has a constant x value (in the y-z plane).

Z-X Symmetry Plane

• Assumes the flow is symmetric across the boundary face and that the entire surface has a constant y value (in the z-x plane).

X-Y Symmetry Plane

• Assumes the flow is symmetric across the boundary face and that the entire surface has a constant z value (in the x-y plane).

Negative Axi-symmetric Wall

• An axi-symmetric side-wall boundary condition. Assumes that the singular line is along the x axis. The angular displacement of the side walls must be exactly -pi/80 or -2.25°. The acute angle in a cross flow pie wedge must be 4.5°.

Positive Axi-symmetric Wall

• An axi-symmetric side-wall boundary condition. Assumes that the singular line is along the x axis. The angular displacement of the side walls must be exactly +pi/80 or +2.25°. The acute angle in a cross flow pie wedge must be 4.5°.

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