Does anybody have an idea about the slow-down of convergence speed when a geometry has high aspect ratio? What I mean is, when ratio of width and length in geometry(i.e. 2D rectangular shape) is high(i.e.1:50 or more than that), it takes much more time(real time) to be converged even the number of control volume is relatively low.

The only problem I know concerning very high aspect geometries, like 1:50 of yours, is numerical diffusion, which tends to accumulate along. Presuming you will use a structured mesh (it has far less cells than unstructured one for this type of geometry), so you will have a relatively low number of nodes, take into consideration double-precision solvers!

Best whishes, Razvan

Thank you. I appreciate your comment.