## Chapter 14: Boundary Conditions

Boundary conditions must be applied to all the bounding regions of your domains. Boundary conditions can be inlets, outlets, openings, walls, and symmetry planes.

Unspecified external regions are automatically assigned a no-slip, adiabatic wall boundary condition. Such regions assume the name `<Domain> Default`, where `<Domain>` corresponds to the name of the domain. Unspecified internal boundaries are ignored.

You can apply boundary conditions to any bounding surface of a 3D primitive that is included in a domain (including internal surfaces). If you choose to specify a boundary condition on an internal surface (for example, to create a thin surface), then boundary conditions must be applied to both sides of the surface.

This chapter describes:

- Default Boundary Condition
- Creating and Editing a Boundary Condition
- Interface Boundary Conditions
- Symmetry Boundary Conditions
- Working with Boundary Conditions

Additional information on boundary conditions is available in:

- The Purpose of Boundary Conditions in the CFX-Solver Modeling Guide

- Available Boundary Conditions in the CFX-Solver Modeling Guide

- Using Boundary Conditions in the CFX-Solver Modeling Guide

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