grid generation of type C
 

I'm using structured grid generation of type C, in numerical simulation of flow about NACA airfoil. The flow supposed 2D, incompressible, viscous and laminar. The method of discretization is finite volumes with second order upwind scheem. For coupling velocities with pressure i'm using SIMPLER algorithm. My problem diverge after a difference of velocity 1.e-3 between two consecutive iterations.

Is that caused by the dimension of grid generation (191x141)and the stretching parameters (0.12,0.12)?