Filling a candy jar with the Swedish Christmas caramel knäck – meshfree DEM particles video tutorial and contest

All of our Swedish blog readers have most probably tasted “knäck”. Knäck is a very popular Swedish Christmas toffee/caramel and the name translates into “crack” and refers to its hard consistency. But few have tried to simulate the process of filling a candy jar with knäck using DEM-particles, and probably even fewer using a mesh-free approach!

In this blog article there is an embedded video tutorial showing how to setup a meshfree DEM simulation in Simcenter STAR-CCM+, see video below. This feature was released in version 2021.3 and significantly reduces the time to set up and run particle flow simulations when fluid flow impact is neglectable.

To acknowledge the upcoming holidays and put a Swedish touch to it, the DEM-particles used in the simulation are shaped as knäck caramels, as you already might have suspected.

The geometry used to capture the shape of the knäck is created in 3D-CAD, and then injected into the simulation using concave polyhedral particles. Concave polyhedral particles were introduced in the first release of this year, Simcenter STAR-CCM+ 2021.1. They can capture any arbitrary shape, and you can specify the shape of the particle via a part, which you may create in the integrated CAD software 3D-CAD, as done in this simulation.

To read more about the meshfree DEM Workflow you are referred to the Simcenter STAR-CCM+ help, at Simcenter STAR-CCM+ -> Simulating physics -> Multiphase flow -> Using the Discrete Element Method -> Meshfree DEM workflow.


For this special Christmas blog post, we have a small contest as well. Via the form below you can submit your best guess of how many knäck DEM particles there are in the candy jar at the end of the animation in the beginning of the video tutorial (at 10 seconds into the video). One lucky (or skilled?) reader will win some Volupe merchandise presented in the picture below. Please submit your best guess and your contact information before the 10th of January, and we will contact the winner for receiving the prizes. Good luck!

Volupe merchandise


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Volupe wishes you a Merry Christmas and a Happy New Year!

knäck DEM mesh free



1 carl s high e1618396736437

Carl Stenson, M.Sc.
+46 766 336 599


Robin Viktor

Robin Victor


Christoffer Volupe

Christoffer Johansson, M.Sc.

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