Kinematic Coupling for wind turbine rotor

[jer25]

Hi All,

Would anyone be able to explain to me how I can apply kinematic coupling to my wind turbine rotor such that it will rotate but the blades wont flex too much. At the roots (first ring of nodes at the blade root) of the blades I have a rigid body constraint applied with the master node being a reference point in the center of the rotor (Image Rigid_coupling). I have a second kinematic coupling setup with the nodes over the rest of the blades and the master node is the RP node again (Image Coupling). When I run the job the blades will not flex. However, when I disable U1 in the coupling constraint the whole turbine floats away in the x direction. All boundary conditions are applied to the RP node which is constrained in the U1 U2 and U3 directions. Anyone know what way I should apply coupling constraints so the the rotor will rotate about the x-axis but allow the blades to flex?

Image (Coupling)

http://files.engineering.com/getfil...bb74-4dec-80e1-aa3487b25b43&file=Coupling.JPG

Image (Rigid_coupling)

http://files.engineering.com/getfil...a7f-88dc-84bfb621b1a0&file=Rigid_coupling.JPG

Kind Regards,
J

 

[cooken]

Place a reference node in the middle of the cross-section at the root of each blade. Then create a local cylindrical coordinate system for each with the origin at the newly created node, with the Z axis aligned with the axis of the blade (perpendicular to the root cross section). Then try the following couplings from the new node at the root centre to the ring of nodes:
1) kinematic coupling with U1 disabled
2) distributing coupling with all enabled

Modify your rigid coupling so that the master node at the centre of rotation only controls the 3 secondary master nodes at the root of each blade. This might not achieve the desired behavior but should get you pretty close I think, and you can try other similar combinations too.

You could also try placing a U1 (global x) boundary condition directly on the root nodes that lie on the XZ plane of symmetry (assuming there is one).