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Flux
Flux is a finite element software for low-frequency electromagnetic and thermal simulations. Both, 2D and 3D solutions are available...
Construction of a Flux project
The construction of a Flux project consists of several stages: Geometry → Mesh → Physics → Resolution → Postprocessing; with the possibility to import a CAD file, a mesh, materials...
Materials: principles
k(T) law: models
Thermal conductivity, exponential function of T

Welcome
User guide
The user guide gives information about principles and how to use Altair® Flux® 2026.
What's New
See the release notes of the last and previous versions, with the necessary information on new features.
"How to" Documents
See a list of documents to understand how to use certain features.
Altair Flux Videos
Several youtube videos about how to use Altair Flux and several tip and tricks
Flux Supervisor
The Flux supervisor allows to run projects, examples, pythons scripts; to configure user preferences; to access tools...
Flux
Flux is a finite element software for low-frequency electromagnetic and thermal simulations. Both, 2D and 3D solutions are available...
- General operation
  Here is a presentation of the Flux environment; the project management, the data management, the command language, the formulas and mathematical functions.
- Construction of a Flux project
  The construction of a Flux project consists of several stages: Geometry → Mesh → Physics → Resolution → Postprocessing; with the possibility to import a CAD file, a mesh, materials...
- Physical applications
  Flux allows to model different physical phenomena, and includes various applications (magnetic, electrical, thermal and thermal coupled).
- Circuit and Kinematic Couplings
  Flux is coupled to a circuit context allowing to model the sources of the devices.Flux also allow to model the movement via a kinematic coupling.
- Co-simulation between Flux and another software
  Flux is able to couple with several software programs allowing to model mutliphysics phenomena.
- Dedicated couplings
  Several dedicated couplings are implemented in Flux to, carry out vibro-acoustic studies, magneto-thermal studies and more.
- 3D Overlay
  Flux has predefined models for rotating machines via Overlays allowing to describe a geometry, a mesh and a physics adapted to the wished machine.
- Flux API
- How to Configure the Memory in Flux?
Flux Skew
Flux Skew is a module dedicated to the analysis of rotating electric machines with skewing, allowing a straightforward geometric and physical description in 2D and the consideration of continuous or step skewing effects.
Material Identification
The Material Identification tool is based on the Altair Compose environment and allows determining from measurements the parameters and coefficients required to create a material in Flux.
Altair Material Datacenter (AMDC)
AMDC is a comprehensive material database maintained by Altair and partner suppliers of engineering materials. Ready-to-use, Flux-compatible models may be obtained directly from this database for a growing number of materials.
Material Manager
Flux has a material manager with its own material base.The user can create his own material base and import them into the Flux models to be studied.
Flux e-Machine Toolbox
FeMt is a application in Flux dedicated for Electric Machine which permits to compute and postprocess results like efficiency maps.
Flux Examples
See the lists of examples 2D and SKEW with all available documents, as well as all project and python files.
Flux in SimLab Examples
See the list of SimLab examples using the Flux and Mipse solvers, with all available documents, *.slb databases, and all script files.
Mementos
See a list of Memento documents to understand certain Flux features.
Macros
Flux proposes several macros enabling doing actions that are not yet implemented in Flux.
PyFlux Documentation (Beta version)
This documentation deals with the Jython script used in Flux and allows to understand the various structures of entities and functions, and use it in user scripts for example.
Flux installation guide
This document provides instructions for Flux installation on supported platforms.
Flux Starting Guide
Several short videos to start with Flux.

Since version 2026, Flux 3D and Flux PEEC are no longer available.

Please use SimLab to create a new 3D project or to import an existing Flux 3D project.

Please use SimLab to create a new PEEC project (not possible to import an existing Flux PEEC project).

/!\ Documentation updates are in progress – some mentions of 3D may still appear.

Thermal conductivity, exponential function of T

Presentation

This model defines a conductivity k as an exponential function of the temperature for an isotropic or anisotropic material.

Mathematical model

The thermal conductivity is an exponential function of the temperature.

The corresponding mathematical formula is written:

where:

T₀ is the reference temperature degree
k_a + k_b is the conductivity of a material at T₀ (W/m/degree)
k_a is a constant quantity (W/m/degree)
τ is a temperature constant (positive or negative) (degree)

The shape of k(T) curve is presented in the figure below.

Anisotropic material

For an anisotropic material, this linear model consists of a group of three exponentials.