VAWT - IEC 61400-2 Rotor diameter definition

Dear all,

I’m starting working on a project related to a VAWT based on the wind conditions given in the IEC 61400-2. Unfortunately, inside that standard the definition of “D” in the case of a VAWT is missed.
For now as a rotor diameter D, I’m using the equivalent diamter definition ( D=2sqrt(A/pi)), but I want to be sure that this is the same approach foreseen in the IEC 61400-2.
Does anyone can give me some information?

Many thanks in advance for your help.

Best regards

I see this equivalent in IEC61400-12-1