The CROSSING project (Crossing Borders and Scales - an interdisciplinary approach) establishes a strategic partnership between Helmholtz-Zentrum Dresden Rossendorf (HZDR) in Germany and the Jožef Stefan Institute (JSI). The purpose of the project is to extend the existing research activities to the sustainable and long-term cooperation of the two institutions. In addition to scientific topics, the project also includes the use and development of the research infrastructure of both organizations. Three scientific sub-projects range from the fields of living matter and material research, environmental chemistry, microbiological technologies and high-performance computing systems and computer simulations. Within the scope of the project, we are dealing primarily with the simulation and development of heat and mass transfer models in the two-phase, stratified gas and liquid streams at the Reactor Engineering Department (R4). In doing so, R4 cooperates with the related computer fluid dynamics section at HZDR, with which we have been individually involved in various European projects over the last ten years.

The purpose of the one-week working visit was to get a more detailed acquaintance and start work with the simulation tools they use on HZDR. These include, among other things, their own programs and extensions developed within the OpenFOAM tool, the GitLab source management system and the virtualization system at the Docker operating system level. During the visit, we also set up some initial examples of simulated flows, which will serve as the starting point for the development of models of heat and mass transfer in the continuation of the project.