User-Defined Function (UDF) Concepts in ANSYS Fluent

Introduction to UDF Concepts

This video aims to talk about User-Defined Function (UDF) Concepts. This lesson will give you a general introduction to the UDF and an overview of using UDF programming in ANSYS Fluent. This product is the first chapter of the UDF training course. We fully and comprehensively introduce you to UDF writing and its importance in Ansys Fluent software.

First, we teach how to run UDF in Fluent software. For this, you can use two methods:

• Compiling
• Interpreting

When you use UDF, there is a link between the UDF commands and the internal data of the Fluent software. So, we introduce a concept called Mesh Terminology. Therefore, we define concepts such as Mesh Components, Structure Data, Threads, Pointers, etc. To program UDF, we must use predefined Macros in Fluent Ansys. So, UDF can be classified based on the type of macros used.

In this training chapter, we introduce different types of commonly used macros. Some of them are:

• General Purpose DEFINE Macros
• Model-Specific DEFIENE Macros
• Multiphase DEFINE Macros
• Discrete Phase Model (DPM) DEFINE Macros
• Dynamic Mesh DEFINE Macros

Each category has several examples of macros, and we introduce some commonly used examples. Then, we explain the use and function of each of these macros. Each of these macros consists of several arguments. We introduce each of these arguments and explain their function.

Some examples of general purpose macros category:

• DEFINE_ADJUST
• DEFINE_DELTAT
• DEFINE_EXECUTE_AT_END
• DEFINE_INIT

Some examples of model-specific macros category:

• DEFINE_PROFILE
• DEFINE_PROPERTY
• DEFINE_SOURCE
• DEFINE_PRANDTL

Some examples of multiphase macros category:

• DEFINE_CAVITATION_RATE
• DEFINE_EXCHANGE_PROPERTY
• DEFINE_MASS_TRANSFER

Some examples of discrete phase model (DPM) macros category:

• DEFINE_DPM_BC
  
• DEFINE_DPM_DRAG
• DEFINE_DPM_EROSION

Some examples of dynamic mesh macros category:

• DEFINE_CG_MOTION
  
• DEFINE_SDOF_PROPERTIES
• DEFINE_GRID_MOTION

In the next section, we introduce some examples of additional macros:

• Data Access Macros
• Looping Macros
• Vector and Dimensions Macros
• Time-Dependent Macros

This product is the 1st chapter of the User-Defined Function (UDF) Training Course.