Hello everybody,

I am trying to model a fully discretized borehole heat exchanger (coaxial). The diameter of the outer ring changes stepwise with the depth. The outer pipe is modeled as a vertical 2D discrete element.

How do I model the change of the diameters of the outer ring? The discrete element representing the smaller diameter is not  underneath the element representing the bigger diameter.  This is because the discrete elements are positioned in the centre of the surplus, the center, of course, differs between the two diameters.

Thanks a lot for your help

Nils Deecke