Boundary Conditions

The table below report an overview of available boundary conditions and specifications. The description specifies the application and the restriction of the boundary conditions.

Boundary availability depends on the application you are currently using.

Boundary Description
INLET - Absolute velocity Inlet velocity - Velocity vector is specified in an absolute reference frame
  • Uabsx [m/s] - Absolute velocity X
  • Uabsy [m/s] - Absolute velocity Y
  • Uabsz [m/s] - Absolute velocity Z
  • Dₕ [m] - Hydraulic diameter
INLET - Cylindrical velocity Inlet velocity in a cylindrical reference frame
  • Centre X [m] - Centre X
  • Centre Y [m] - Centre Y
  • Centre Z [m] - Centre Z
  • Axis X - Normalized axis X
  • Axis Y - Normalized axis Y
  • Axis Z - Normalized axis Z
  • U axial [m/s] - Axial velocity
  • U radial [m/s] - Radial velocity
  • ω [rpm] - Rotational velocity
  • Dₕ [m] - Hydraulic diameter
INLET - Relative velocity Inlet velocity - Velocity vector is specified in a relative reference frame
  • Urelx [m/s] - Relative velocity X
  • Urely [m/s] - Relative velocity Y
  • Urelz [m/s] - Relative velocity Z
  • Dₕ [m] - Hydraulic diameter
INLET - Total pressure Total pressure inlet condition - valid also for outlet condition
  • p₀ [Pa] - Total Pressure
  • Dₕ [m] - Hydraulic diameter
INLET - Velocity Inlet velocity - Velocity vector normal to the surface (use negative value for outflow)
  • U [m/s] - Velocity
  • Dₕ [m] - Hydraulic diameter
  • Φ [%] - Fluid-A concentration
INLET - Velocity and particles Inlet velocity with specified inlet particles
  • U [m/s] - Fluid velocity
  • Uxp [m/s] - Particles velocity X
  • Uyp [m/s] - Particles velocity Y
  • Uzp [m/s] - Particles velocity Z
  • Mp [kg/s] - Particles mass flow
  • Dp [m] - Particles dimension
  • Dₕ [m] - Hydraulic diameter
INLET - Velocity fixed temperature Inlet velocity with specified temperature - Velocity vector normal to the surface
  • U [m/s] - Velocity
  • T [K] - Temperature
  • Dₕ [m] - Hydraulic diameter
INLET - Velocity vector Inlet velocity where the user specifies the velocity vector
  • Ux [m/s] - Velocity X
  • Uy [m/s] - Velocity Y
  • Uz [m/s] - Velocity Z
  • Dₕ [m] - Hydraulic diameter
  • Φ [%] - Fluid-A concentration
INLET - Velocity vector fixed temperature Inlet velocity where the user specifies the velocity vector and the temperature
  • Ux [m/s] - Velocity X
  • Uy [m/s] - Velocity Y
  • Uz [m/s] - Velocity Z
  • T [K] - Temperature
  • Dₕ [m] - Hydraulic diameter
INLET - Volume flow Inlet condition with prescribed volume flow (use negative value for outflow)
  • Q [m³/s] - Volume flow
  • Dₕ [m] - Hydraulic diameter
OUTLET - Pressure Outlet condition for pressure - Backscatter flow is denied
  • p [Pa] - Pressure
WALL - Adiabatic no slip No slip adiabatic wall
  • Ux [m/s] - Velocity X
  • Uy [m/s] - Velocity Y
  • Uz [m/s] - Velocity Z
WALL - Fire fixed temperature No slip wall with prescribed temperature
  • Ux [m/s] - Velocity X
  • Uy [m/s] - Velocity Y
  • Uz [m/s] - Velocity Z
  • CO [kg/(s·m²)] - CO production
  • T [K] - Temperature
WALL - Fire heat flux No slip wall with imposed temperature gradient
  • Ux [m/s] - Velocity X
  • Uy [m/s] - Velocity Y
  • Uz [m/s] - Velocity Z
  • CO [kg/(s·m²)] - CO production
  • T [K/m] - Temperature gradient
WALL - Fire location No slip wall with imposed temperature gradient
  • Ux [m/s] - Velocity X
  • Uy [m/s] - Velocity Y
  • Uz [m/s] - Velocity Z
  • CO [kg/(s·m²)] - CO production
  • q [W/m²] - Heat flux
WALL - No slip No slip adiabatic wall
  • Ux [m/s] - Velocity X
  • Uy [m/s] - Velocity Y
  • Uz [m/s] - Velocity Z
WALL - No slip fixed temperature No slip wall with imposed temperature
  • Ux [m/s] - Velocity X
  • Uy [m/s] - Velocity Y
  • Uz [m/s] - Velocity Z
  • T [K] - Temperature
WALL - No slip rough wall No slip rough wall
  • Ux [m/s] - Velocity X
  • Uy [m/s] - Velocity Y
  • Uz [m/s] - Velocity Z
  • Ks [m] - Sand-grain roughness height
  • Cs - Roughness constant
WALL - No slip with CO production No slip wall with imposed CO production
  • Ux [m/s] - Velocity X
  • Uy [m/s] - Velocity Y
  • Uz [m/s] - Velocity Z
  • CO [kg/(s·m²)] - CO production
WALL - No slip with heat flux No slip wall with imposed heat flux per surface unit
  • Ux [m/s] - Velocity X
  • Uy [m/s] - Velocity Y
  • Uz [m/s] - Velocity Z
  • q [W/m²] - Heat flux
WALL - No slip with heat power No slip wall with imposed global heat flux
  • Ux [m/s] - Velocity X
  • Uy [m/s] - Velocity Y
  • Uz [m/s] - Velocity Z
  • Q [W] - Heat power
WALL - Rotating Rotating adiabatic wall
  • Centre X [m] - Centre X
  • Centre Y [m] - Centre Y
  • Centre Z [m] - Centre Z
  • Axis X - Normalized axis X
  • Axis Y - Normalized axis Y
  • Axis Z - Normalized axis Z
  • ω [rpm] - Rotational velocity
WALL - Rotating no slip Rotating adiabatic wall
  • ω [rpm] - Relative rotational speed
WALL - Rotating no slip rough wall No slip rotating rough wall
  • ω [rpm] - Relative rotational speed
  • Ks [m] - Sand-grain roughness height
  • Cs - Roughness constant