This folder contains files to use COMSOL as the structural solver in an FSI simulation. Since it was not possible to directly couple the C++ coded preCICE to the COMSOL API, we used FSI*ce as intermediate communication/data library. There are, hence, two important files: comsol_simulation.c, the interface with the COMSOL API, which uses FSI*ce to communicate the data to the intermediate (executable) component ComsolPrecice.c. ComsolPrecice uses FSI*ce to exchange data with comsol_simulation, and preCICE for the actual coupling.

Only 2D simulations have been done so far. For 3D, several changes to comsol_simulation.c and some to ComsolPrecice.c have to be done.

The compilation is done by SCons, check the SConstruct script for detailed information on the build variables. There is a debug and a release mode.

comsol_simulation.c is compiled and linked into a shared object (.so). For that, it needs (among others) the pathes to the COMSOL installation, and the FSI*ce libraries. These paths are hardcoded in the SConstruct file.

ComsolPrecice.c is compiled into an executable. For that, it needs (among others) the pathes to the FSI*ce libraries and the preCICE library.

There are two executables to be run (in any order). The Comsol script needs to be run as follows

$ comsol script simulation

The keyword "simulation" tells the COMSOL script to run the simulation.m file in the current directory. It can also be omitted and given in the scripting GUI. To run COMSOL script without GUI, type

$ comsol script -term

Wait until comsol started, then type

$> flreport('off') $> simulation

To run ComsolPrecice, type

./ComsolPrecice Comsol precice_config.xml

Where COMSOL gives the name of the participant to preCICE, and precice_config.xml tells preCICE where to find the coupling configuration.

HINT: Sometimes, after killing the COMSOL script, it happens that COMSOL starts, but doesn't load the simulation.m file. It suffices to close and restart it.