# FIELD_BOUNDARY_CONDITION

Specifies field element and nodal boundary conditions on a set of element faces referred to in SIMPLE_BOUNDARY_CONDITION.

## Type

AcuSolve Command

## Syntax

FIELD_BOUNDARY_CONDITION("name") {parameters...}

## Qualifier

User-given name.

## Parameters

- type (enumerated) [=value]
- Type of the boundary condition imposition.
- value
- Field nodal values.
- flux
- Field volume fraction flux values. Valid only for multi_field= eulerian_eulerian.

- value (real) [=0.0]
- Field nodal values to be imposed on nodes associated with surface elements referred to in SIMPLE_BOUNDARY_CONDITION. For multi_field=levelset, algebraic_eulerian, eulerian_eulerian, field volume fraction should be provided. However, for multi_field=advective_diffusive, the mass fraction value of the field should be given.
- flux (real) [=0.0]
- Field volume fraction flux to be imposed on surface elements referred to in SIMPLE_BOUNDARY_CONDITION. Valid only for multi_field= eulerian_eulerian and needed for dispersed field. For fluidization type problems, the flux value for solid phase should be set to zero in the inlet.
- field (string) [no default]
- Name of the field that value or flux is associated with. Field should be an active field in the problem. This should be given for all multi_field types.
- multiplier_function (string) [=none]
- User-given name of the multiplier function for scaling the boundary condition values. If none, no scaling is performed.
- phasic_inflow_type (enumerated) [=cartesian_velocity]
- Type of the inflow phasic velocity boundary conditions. Used with
multi_field= eulerian_eulerian
only.
- cartesian_velocity
- Velocity in cartesian coordinates. Requires x_velocity, y_velocity, and z_velocity.
- cylindrical_velocity
- Velocity in cylindrical coordinates. Requires cylinder_axis, axial_velocity, radial_velocity, and tangential_velocity.
- spherical_velocity
- Radial velocity component in spherical coordinates. The other two components are zero. Requires sphere_center and radial_velocity.
- normal_velocity
- Velocity component normal to surface. The other two components are zero. Requires normal_velocity.
- mass_flux or mass
- Integrated mass flux (equivalent to mass flow rate) and nodal scalars (except eddy viscosity).
- flow_rate or flow
- Integrated volume flux (equivalent to volumetric flow rate) and nodal scalars (except eddy viscosity).

- cylinder_axis (array) [={0,0,0; 0,1,0}]
- Coordinates of two points that define the axis of the cylinder. Used with phasic_inflow_type= cylindrical_velocity type.
- sphere_center (array) [={0,0,0}]
- Coordinates of the center of the sphere. Used with phasic_inflow_type= spherical_velocity.
- x_velocity or xvel (real) [=0]
- Value of the x-velocity. Used with phasic_inflow_type= cartesian_velocity.
- x_velocity_multiplier_function (string) [=none]
- User-given name of the multiplier function for scaling the x-velocity boundary condition value. If none, no scaling is performed. Used with phasic_inflow_type= cartesian_velocity.
- y_velocity or yvel (real) [=0]
- Value of the y-velocity. Used with phasic_inflow_type= cartesian_velocity.
- y_velocity_multiplier_function (string) [=none]
- User-given name of the multiplier function for scaling the y-velocity boundary condition value. If none, no scaling is performed. Used with phasic_inflow_type= cartesian_velocity.
- z_velocity or zvel (real) [=0]
- Value of the z-velocity. Used with phasic_inflow_type= cartesian_velocity.
- z_velocity_multiplier_function (string) [=none]
- User-given name of the multiplier function for scaling the z-velocity boundary condition value. If none, no scaling is performed. Used with phasic_inflow_type= cartesian_velocity.
- axial_velocity (real) [=0]
- Value of the axial velocity. Used with phasic_inflow_type=cylindrical_velocity.
- axial_velocity_multiplier_function (string) [=none]
- User-given name of the multiplier function for scaling the axial velocity boundary condition value. If none, no scaling is performed. Used with axial_velocity.
- radial_velocity (real) [=0]
- Value of the radial velocity. Used with phasic_inflow_type= cylindrical_velocity.
- radial_velocity_multiplier_function (string) [=none]
- User-given name of the multiplier function for scaling the radial velocity boundary condition value. If none, no scaling is performed. Used with radial_velocity.
- tangential_velocity (real) [=0]
- Value of the tangential velocity. Used with phasic_inflow_type= cylindrical_velocity.
- tangential_velocity_multiplier_function (string) [=none]
- User-given name of the multiplier function for scaling the tangential velocity boundary condition value. If none, no scaling is performed. Used with tangential_velocity.
- normal_velocity (real) [=0]
- Value of the normal velocity. Used with phasic_inflow_type= normal_velocity.
- normal_velocity_multiplier_function (string) [=none]
- User-given name of the multiplier function for scaling the normal velocity boundary condition value. If none, no scaling is performed. Used with normal_velocity.
- mass_flux or mass (real) >0 [=1]
- Value of the integrated mass flux. Used with phasic_inflow_type= mass_flux.
- mass_flux_multiplier_function (string) [=none]
- User-given name of the multiplier function for scaling the integrated mass flux value. If none, no scaling is performed. Used with inflow type and mass_flux inflow type.
- flow_rate or flow (real) >0 [=1]
- Value of the integrated flow rate. Used with phasic_inflow_type= flow_rate.
- flow_rate_multiplier_function (string) [=none]
- User-given name of the multiplier function for scaling the integrated flow rate value. If none, no scaling is performed. Used with inflow type and flow_rate inflow type.
- average_velocity or ave_vel (real) >0 [=1]
- Value of the average velocity. Used with inflow type and average_velocity inflow type.
- average_velocity_multiplier_function (string) [=none]
- User-given name of the multiplier function for scaling the average velocity value. If none, no scaling is performed. Used with inflow type and average_velocity inflow type.