[chriss85]

For transient cases consisting out of a mesh where the flow reaches certain parts of the mesh later in the simulation, I would expect it to be beneficial if the equations were solved on a subset of the mesh in which there is an actual change of variables. Especially when the speeds are higher at the start due to an expanding flow I would expect a relevant speedup here.

I realize this could be done manually by using the mapFields utility but I'm wondering if anyone has attempted to do something like this automatically?

I would suspect one would do it by specifying a starting cell, and then progressively searching all its neighbous (breadth-first search), while checking the differences in the solution of different time steps. Once differences are found, remove n levels of neighbours from the set so that changes can propagate to the cells that were inactive before. When done, remove all cells in the set from the mesh, map fields and continue. Each time this would need to start from the complete mesh of course.

Depending on the time needed for this procedure, this could be executed every few steps.

If anyone is aware of such a concept or has thoughts about it feel free to discuss it here!