Aras karimi

I expected you to say that the aspect ratio is a large number. Well, consider that  mesh1 and 2 have the same aspect ratio, with the difference that  mesh1 has very good convergence and  mesh2 with a message on the console and fluctuating resolutions and practically no convergence.

My mesh is as follows:


In the figure below, as you can see, the aspect ratio very large is related to the back of the airfoil:


To reduce the aspect ratio, the mesh behind the airfoil should be very small ?  If this is the case, the number of mesh cells will increase and it is worrying.

What do you mean by mesh quality? Do you mean the growth rate of block lines?