FIDYST – Fiber Dynamics Simulation Tool

The simulation software FIDYST is a highly efficient software in order to simulate elastic fibers in turbulent fluid flows. On the basis of the theory of Cosserat-Rods FIDYST models the dynamics of elastic, line shaped objects in a very general way.

Hence, there is a broad spectrum of different applications for FIDYST. Of particular importance are the applications of FIDYST in the production processes of technical textiles. Not till the Fraunhofer ITWM has developed a turbulent air drag model it is possible to simulate the fiber dynamics in real industrial applications.

Industrial Applications

Several industrial companies use FIDYST to optimize their nonwovens production processes.

With FIDYST they improve:

  • Spunbond processes,
  • Meltblown processes, and
  • Airlay processes.

The engineers systematic use the fiber dynamics simulation in order to design the machinery as well as the process parameters. The goal of the optimization is to increase the product quality while at the same time the production costs should decrease (lower energy costs or raw material consumption, respectively).

Software FIDYST
© Fraunhofer ITWM
FIDYST with Graphical User Interface showing a spunbond airflow and filament simulation.


  • FIDYST is patform independent and runs on Windows and Linux.
  • The CFD data is imported in the EnSight Gold Case Format. Hence any flow solver can be used. A typical example is Ansys FLUENT.
  • The geometry is detected automatically and triangulated, in order to simulate the fiber-wall contact efficiently.
  • The material parameters of the fibers are specified by a help assistant with tooltips.
  • The export format of the fiber dynamics simulation is the EnSight Gold Case Format. Hence, the simulation results can be visualized and analyzed by standard software tools.
© Fraunhofer ITWM
Simulation Spunbond Process
© Fraunhofer ITWM
Simulation Airlay Process