STL intersecting domain boundary


When running the example externalFlowAroundObstacle with default obstacle placement everything works as expected. However, when the obstacle is moved to intersect the domain boundary (see picture) the solver crashes with the following error:

Caught exception in process 0. Palabos generic exception: 
  List of error messages (not chronological):
    1) Error treating the geometry in the Guo off-lattice model.
    2) Guo off-lattice model could not find an intersection with a triangle.

The only modification from the original example is in the externalFlowAroundObstacle.xml file changing the obstacle location.

The same problem arises with many other examples. How to avoid this? My end goal is to run wind simulations in build environment with multiple buildings.

Best regards,
Antti Mikkonen

Hey Amikkonen,
The issue here is that the moment you have your obstacle outside the domain you have nodes outside the domain, leading to incomplete triangles.
You just have to make sure your geometries are always inside the domain, if you want something flush against the wall just cut it in half and then move it into position.

Thank you for the answer. However, that sounds like a lot of work :slight_smile: One of the main motivators for using LBM for me is to avoid the preprocessing steps associated with FVM. Are there any more robust algorithms available?