Airfoil characteristics for 90deg

Why should we know the airfoil cl, cd values beyond the stall angle for fixed pitch stall regulated wind turbines. Fact i understood is it is working for various Reynolds number , hence the AOA differ from the optimum. But what is the range of AOA should be consider for airfoil analysis.

Thank you

Dear Suni,

If you are considering aero-elastic simulations (using e.g., FAST) and plan to run through a series of IEC-style design load cases, we typically recommend that your airfoil data covers the complete 360-deg range of AoA (-180 <= AoA <= 180) because many cases involve extreme conditions (e.g. large gusts, direction changes, or yaw errors) that could lead to AoAs outside of their normal operational range. It is better to be safe, than for the simulation to abort because the AoA ends up outside the valid range.

Best regards,