Question about MergePatchPairs and StichMesh
 

I have a Mesh that contains of three big regions i must combine. However in my current situation after a decent amount of timesteps my Delta t is shrinking to a very tiny size. ex.: dt=k*10 exp(-18) and below.

I found out that this is a result of bad connected regions. Therefore i want to know, which mesh combining method is better.

I`m trying to combine a cylindrical ring (axis in z direction) with another cylinder (axis in x-direction).

Because of that i must know if im better using stichMesh oder MergePatchpairs.

If you cannot give an answer, than could you please explain the differences between those two techniques?