Question

How does the blade element theory treat the airfoil as?

(a) One-dimensional

(b) Two-dimensional

(c) Three-dimensional

(d) One complete body

The question was asked during an interview for a job.

I'd like to ask this question from Blade Element Theory topic in division Helicopter Dynamics of Aerodynamics

Answer 1

Right answer is (b) Two-dimensional

The explanation is: The essence of blade element theory is to divide the blade into numerous segments known as blade elements. These are considered to be independent and not influencing the flow over other elements. Thus, it is treated as a two-dimensional airfoil whose aerodynamic forces are computed based on local flow conditions at that particular element instead of the entire airfoil.