文档介绍：Boundary and Initial Conditions
Introduction
Boundary conditions are required to set on all external domain boundaries
Initial values/guess are required to set for all calculations
Boundary conditions and initial values/guess can be either constants or expressions
Boundary Conditions
Default external boundary condition: adiabatic, no-slip wall
Available boundary conditions:
Inlets
Outlets
Openings
Walls
Symmetry Planes
Periodic Pairs (GGI Periodic not support with Multi-phase flows)
It is generally possible to specify different type options for different fluids on the same boundary condition with the same general boundary condition type
Boundary Condition Forms (single-phase)
Specify name (will be referred to in post-processor)
Select boundary condition type
Select surfaces on which to apply the boundary condition
Specify boundary condition values
Boundary Conditions
A sample values form
Values change according to BC type
Inlet - speed/velocity, pressure, mass flow
Wall - No slip, free slip, moving, counter rotating, wall roughness
Opening - velocity, pressure
Also specify additional variables and MCF/2-Phase settings
Some options governed by domain settings
Boundary Conditions (multi-phase)
Inlet/Outlet
Inlets/Outlets
Flow is allowed into domain for inlet or out of domain for outlet
Artificial walls are built to prevent reverse flow
Need to specify some of the following quantities at the inlet: velocity, total/static pressure, mass flow rate, temperature, turbulent quantities, additional scalars, mass fractions and volume fractions
For rotating frame of reference all velocities are in rotating frame (except for the case when total pressure in stationary frame is specified along with ponent direction)
Degassing Outlet for Multi-phase
Mixed boundary conditions are required to account for simulations where one fluid may flow out of or into the domain through the boundary but other fluids may not
This is a typical requirement of bubble column applica