Forum
Important Notice for New User Registrations
To combat an increasing number of spam and bot registrations, we now manually approve all new user registrations. While this may cause a delay until your account is approved, this step is essential to ensure the quality and security of this forum.
To help us verify your registration as legitimate, please use a clear name as user name or an official email address (such as a work, university, or similar address). If you’re concerned that we may not recognize your registration as non-spam, feel free to email us at with a request to approve your username.
Force and Moment of Blade
There are the following data in the output from aerodynamics simulation:
- Normal Force Blade [N/m]
- Tangential Force Blade [N/m]
- Pitching Moment Blade [Nm/m]
I would like to know the direction of each force. The direction I understand is shown on the attached figure. Is this correct?
In order to get force [N] or moment [Nm] for each panel, is it needed to multiply each panel length by each force [N/m] or moment [Nm/m]?
BR,
Kensaku
Uploaded files:- You need to login to have access to uploads.
Hello Kensaku,
the normal and tangential directions are defined relative to the blade rotation.
- Horizontal-Axis Wind Turbines (HAWTs): For this turbine type, ‘normal’ and ‘tangential’ directions are defined in relation to the rotor disc. Specifically, these directions are oriented normal to and tangential to the rotor disc at the current position of each blade.
- Vertical-Axis Wind Turbines (VAWTs): For VAWTs, ‘normal’ and ‘tangential’ are defined relative to the circular path traced by the blades.
These forces are indicated per blade length in the unit [N/m], the moments in the unit [N]. So you are correct that you need to integrate these forces/moments per length along the blade span to arrive at the total blade loads.
BR,
David
Thank you, David-san.
Regarding the orientation of the pitch moment of the blade in VAWTs, which orientation is positive? the clockwise is positive based on the view from the top?
BR
Hello Kensaku,
per definition a positive aerodynamic pitch moment results in a node-up rotation of the airfoil.
If you look at the blade torsion sensors when a structural model in included they are defined according to the local blade coordinate system, see:
https://docs.qblade.org/src/user/coordinates/coordinates.html#local-blade-coordinate-system
BR,
David
