An OpenMI module for the groundwater flow simulation programme Feflow

The OpenMI standard defines an interface that allows time-dependent models to exchange data at runtime. The migration of a flow simulation programme to OpenMI compliance usually requires changes in the source code or even a reorganisation of the programme sequence. Users of commercial flow simulation programmes depend on the software producer if they want to couple their models according to the OpenMI standard. We describe how we made the groundwater flow simulation programme Feflow OpenMI compliant without changing the source code: an OpenMI-compliant control application communicates with Feflow via remote procedure calls. A basic prerequisite for applying this method is an entry point into the flow simulation programme that allows to modify the model data during runtime and to implement the remote procedure calls. Feflow meets this requirement as it provides the interface manager (IFM). The mode of operation is explained with a simple test case including an inundation model and a Feflow groundwater model.