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CHAPTER
5 Cell Zone and

Boundary Conditions

In this Chapter
5.1 Introduction
5.2 Cell Zone Conditions
5.3 Boundary Conditions

5.1 Introduction

This chapter describes the cell zone and boundary condition options available in ANSYS FLUENT.
Details regarding the cell zone and boundary condition inputs and the internal treatment at
boundaries are provided.
The information in this chapter is divided into the following sections:
1. Overview

2. Cell Zone Conditions
3. Boundary Conditions

Cell zone and boundary conditions specify the flow and thermal variables on the boundaries of your
physical model. They are, therefore, a critical component of your ANSYS FLUENT simulations and it is
important that these are specified appropriately. Available Cell Zone and Boundary Types The
boundary types available in ANSYS FLUENT are classified as follows:

Flow inlet and exit boundaries: pressure inlet, velocity inlet, mass flow inlet, and inlet vent, intake fan,
pressure outlet, pressure far-field, outflow, outlet vent, and exhaust fan.
Wall, repeating, and pole boundaries: wall, symmetry, periodic, and axis. Internal face boundaries: fan,
radiator, porous jump, wall, and interior.
Cell zones consist of fluids and solids, with porous media treated as a type of fluid zone. (The internal
face boundary conditions are defined on cell faces, which means that they do not have a finite
thickness and they provide a means of introducing a step change in flow properties. These boundary
conditions are used to implement physical models representing fans, thin porous membranes, and
radiators. The “interior” type of internal face zone does not require any input from you.) In this
chapter, the cell zones and boundary conditions listed above will be described in detail, and an
explanation of how to set them and where they are most appropriately used will be provided.

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