Question:

What is the "equal annuli area" approach ?

Answer:

The "equal annuli area" approach is used in blade element model. It is an effective way to optimize the airload computational accuracy while using a minimal number of blade elements. Using the equal annuli area approach, the blade segments are generated so that the annuli areas cut by each segment are equal to each other. This renders smaller segments toward the blade tip and results in higher modeling accuracy for blade airload calculation.