# Equation Syntax Articles and Tutorials

## Modeling and Simulation of Axisymmetric Swirling Flows

Fluid Flow Simulations with Swirl Effects Fluid flows with swirl effects can occur in rotationally symmetric geometries where the azimuthal or angular velocity component is non-zero. In this case one must solve the fully three-dimensional Navier-Stokes equations. However, due to the assumption that azimuthal variations …

## Euler-Bernoulli Beam - FEATool Modeling and Implementation Example

This post will discuss how to implement and model elastic deformations of simple beams with FEATool Multiphysics. Although also available as a pre-defined physics mode and GUI option, beams and truss structures can also be implemented and accurately simulated with slight extension of the available FEM Matlab functions …

## Multiphysics Modeling of Heat Induced Stress in a Brake Disk

This tutorial illustrates how to couple a heat transfer model with linear elasticity by manually defining the multiphysics equations with the FEATool PDE syntax. The custom model examines how temperature rise in a brake disk under braking results in heat induced displacements with resulting increased stresses and …

## Custom Equations and the Weak PDE Formulation Equation Syntax

The following post further examines PDE equation parsing and specifying custom equations in FEATool. Furthermore, a simple parametric heat transfer model will be shown and set up as a custom PDE equation, suitable for both the Matlab command line and m-script file modeling. Stationary heat transfer by conduction and …

## Axisymmetric Modeling Using the Custom Equation Syntax

FEATool has been designed to be able to perform Octave and Matlab multiphysics simulations in all spatial dimensions (1D, 2D, and 3D). However, running full 3D simulations often requires a significant amount of computational resources, that is memory and simulation time. It is therefore desirable to find …

## Modeling with Custom Equations in the FEATool GUI

FEATool Multiphysics features an equation parser which allows users to very easily implement and simulate custom systems of equations. The goal as always with FEATool is to make it as easy as possible, the parser can therefore interpret equations written almost as one would on paper. For example a two dimensional …

## Adding Multiphysics Equations and Using Complex Expressions

The FEATool GUI makes it easy to add and coupled multiphysics equations and complex expressions to your models. This post illustrates how to do this. After starting to work with a physics mode it is easy to add one or more other modes by going to the + tab in the Equation Settings dialog box. There you can simply …