Using the GUI to set up a coupled simulation

In this tutorial we show how to set up a coupled CFD-DEM simulation using the GUI. The case consists of a pure DEM simulation for initializing a particle bed (DEM_init) and a DEM simulation for the coupled run (DEM_run). A pure CFD setup is provided as zip file (CFD_original.zip) - it must be extracted and renamed to CFD during the case setup. This pure CFD setup can be transformed to a coupled CFD folder with the aid of the CFD-DEM Setup tab. The CFD_coupled.zip folder contains the transformed CFD case already, if you want to launch the coupled case right away please unzip this folder and rename it to CFD.

A step-by-step instruction of how to set up & run the simulation is shown in this <https://vimeo.com/649446884/80c7ddc864> screencast.

Warning

Please not that this tutorial only works if you have an installation of CFDEMcoupling on your machine! The GUI workflow can be used for setting up simulations on Windows, but running the simulation in the explained way only works for Linux!

Running the simulation

There are two possibilities to launch the simulation:

1) Split run: Aspherix and the CFDEMcoupling solver can be launched in a side-by-side mode. Please open the project in the GUI and move to the Simulation tab of the DEM_run case. At the same time open a terminal and navigate to the CFD folder (must either be converted to the coupled folder by yourself or the unzipped CFD_coupled.zip folder that was renamed to CFD). Then prepare the CFD simulation (run blockMesh & decomposePar). Then type “mpirun -np 4 cfdemSolverPiso -parallel” in the terminal and hit enter. Without loosing much time click the “Run simulation” button in the GUI. The global DEM output is visulized in the GUI while the simulation is running.

2) Combined run command: the “cfdemSimulate” command can be used to launch a coupled simulation directly within the terminal and with a single command. It does not require a separate simulation launch of the DEM part of the case within the GUI. Please type “cfdemSimulate –help” to check the options for this command. When launching the simulation this way the global DEM output in the GUI is not updated.

Visualizing the results

The output of the DEM simulation and the CFD simulation can both be loaded in Paraview. Macros are taking over the postprocessing and the time steps are synchronized automatically.