Fluent UDF 15.0 L01 Introduction

Lecture 1: Introduction 15.0 Release

User Defined Functions in ANSYS Fluent

Why use User Defined Functions (UDFs)? The Fluent solver is a general-purpose general-purp ose code. In order to customize the Fluent solver, users can use their own C-codes called user-defined functions (UDFs) to (UDFs) to accomplish: Special boundary conditions Customized or solution dependent material properties New physical models Reaction rates Source terms Customized post-processing post -processing Solving user-supplied partial differential equations More …. •

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Why use User Defined Functions (UDFs)? The Fluent solver is a general-purpose general-purp ose code. In order to customize the Fluent solver, users can use their own C-codes called user-defined functions (UDFs) to (UDFs) to accomplish: Special boundary conditions Customized or solution dependent material properties New physical models Reaction rates Source terms Customized post-processing post -processing Solving user-supplied partial differential equations More …. •

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What are User Defined Functions? Programs written in C Similar mechanism used to develop models in Fluent  – Powerful and efficient

Extends the functionality of ANSYS Fluent  – Initial and boundary conditions  – Material properties  – Material and energy transfer through source terms  – Modify solution variables  – Adding extra flow equations  – And many more …

Typically compiled to DLLs/shared object libraries  – Loaded only when required

Sinusoidal Wall Temperature Variation

Adiabatic wall inlet

outlet

Heated wall T = T(x) T(x) =  +  

 .

What Does It Take to Create a Model? Ability to access and modify  – Interact with the user through a GUI/TUI  – Field variables  – Geometrical and mesh data  – Hooks to the solver at appropriate stages of the solution cycle  – Convenience macros •

Vector macros

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Looping macros

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Parallel programming

Basics of UDFs 15.0 Release

User Defined Functions in ANSYS Fluent

C – The Foundation for UDFs UDFs when compiled create C libraries that Fluent can use Resources to learn C