In the Initial Conditions panel you define conditions at the beginning of the simulation (usually denoted by time 0). In the case of steady state simulation values defined here will be the initial approximation of the iterative process and can greatly influence the stability and convergence rate.
There are four basic methods for defining initial conditions:
Basic – all fields are initialized using a specific value or formula
Potential – pressure and velocity can be initialized using potential flow equations
Patch – fields can be initialized to a different values inside specific geometries
Map – fields can be initialized using results from another simulation