Aerodynamic forces from AeroDyn

Hello everybody,

I am modeling an upwind turbine, with zero yaw angle. Wind is blowing to the rotor such that it makes a 90 degree angle with the rotor plane. As it can be read in the AeroDyn User’s guide, AeroDyn can give us the aerodynamic forces normal and tangential to the plane of rotation for each blade element. I would like to know the sign convention of the output, what does it mean when the forceN, forceT are negative or positive?

Furthermore, I appreciate it if you could let me know whether the orientation of the tangential force acting on a blade element is fixed with time or it depends on the position of the blade in the rotor plane (I am asking this because I would like to know whether I can sum up the forceT acting on all the blade elements in three blades at a fixed time, and consider it as the total tangential aerodynamic force at that time) .

Best Regards
Sara

Dear Sara,

I’ve answered your identical question in my posted dated April 10, 2012 found here: http://forums.nrel.gov/t/aerodyn-outputs/392/1.

Best regards,