[Shenren_CN]

Hello all,

I have a quite basic CFD question to ask: How does a steady flow solver manage to get a steady flow solution when the flow is intrinsically unsteady? For example, when I run a simple case of Re=50 laminar flow around a naca airfoil with a blunt trailing edge. If the mesh is coarse enough, my NS solver can converge to machine precision easily; but if the mesh is refined enough, the solver goes to a LCO, although the convergence level is also relatively low. Could anyone give me some hint on how to look at this phenomenon?

I find it hard to ask the "right" question here, but my first question would be: how does the coarse mesh suppress the unsteadiness and help with the convergence to "steady state"? Then, how is linear/nonlinear stability play a role in this?

Thanks in advance.

Shenren