## Chapter 14: CFX Expression Language (CEL)

CFX Expression Language (CEL) is an interpreted, declarative language that has been developed to enable CFX users to enhance their simulations without recourse to writing and linking separate external Fortran routines.

You can use CEL expressions anywhere a value is required for input in ANSYS CFX.

CEL can be used to:

- Define material properties that depend on other variables.

- Specify complex boundary conditions.

- Add terms to the solved equations.

You can also monitor the value of an expression during the solution using monitor points.

Note: CFX-Pre and CFD-Post evaluate CEL expressions with single (not double) precision.

Important: There is some CEL that works elsewhere in ANSYS CFX, but not in CFD-Post. Any expression created in CFX-Pre and used as a Design Exploration output parameter could potentially cause fatal errors during the Design Exploration run, so you should create all expressions for Design Exploration output parameters in CFD-Post.

This chapter describes:

- CEL Fundamentals
- CEL Operators, Constants, and Expressions
- CEL Examples
- CEL Technical Details

Release 18.2 - © ANSYS, Inc. All rights reserved.