7 Replies Latest reply on Mar 20, 2017 3:20 PM by Ryan Dark

    Lift and Drag co-efficient on wind turbine blade?

    Ben Arnold

      Hello my question is whether it is possible to find the lift and drag co-efficient across a wind turbine blade? I can see that it can be done on an object with uniform flow passing over it, however the wind turbine blade will be simulated as a rotating object so therefore there will be different wind speeds experienced across its radius. Thanks very much for the help!!

        • Re: Lift and Drag co-efficient on wind turbine blade?
          Ryan Dark

          Hi Ben,

          You can accomplish this type of setup with the use of a Rotating Region in Flow Simulation.  You would place one or all of your wind turbine blades into a Rotating Region that is set the angular speed you want to test them at.  The program will force a rotating flow across the blades and give you the difference in drag on the blade according to radius from the center of rotation.  This video (GoEngineer - Flow Simulation: Rotating Regions) shows a setup for rotating regions across toy helicopter propellers starting at 20:00.  The setup would be the same for you on your turbine blades.

            • Re: Lift and Drag co-efficient on wind turbine blade?
              Ben Arnold

              Hi Ryan,

              Thanks so much for your answer. Will watch the video and come back if I have further questions.

              • Re: Lift and Drag co-efficient on wind turbine blade?
                Ben Arnold

                Hi Ryan,

                I have set up the rotating region. Just a couple of questions,

                 

                Would the analysis not be different as the wind turbine is extracting energy from the air whilst the the helicopter is putting energy in to the air? Also I am unsure of how to find drag on the blade across the radius? Is it a surface goal of 'friction force' in a certain orientation? Can you use the 'force' goal to find thrust in this set up?

                 

                My main concern about this is that I cannot find a tutorial specifically for a wind turbine which is extracting energy from the air flow rather than rotating due to an external force, ie the helicopters motor.

                 

                Thanks for the help!

                 

                (Reposted as I realised I was replying to my own question and not your answer!)

                  • Re: Lift and Drag co-efficient on wind turbine blade?
                    Ryan Dark

                    Hi Ben,

                    Just brainstorming here but maybe, as a first step, you want to setup your blades in an external environment then and just direct the flow over them to see what the drag forces are as it is still.  Then add a rotating region to see how the drag forces change as the turbine is moving at different speeds.  That might be a more intuitive approach to your problem.  I still think you will want to involve the rotating regions to account for blade movement at some point though.

                    Drag force as going to involve all the forces on the blade so you would probably wish to measure total force not just friction.  If you need more discrete data then you may need to split the face of your blade into radial sections so you can query the "total" force on those discrete faces near and far from the hub.

                • Re: Lift and Drag co-efficient on wind turbine blade?
                  Ben Arnold

                  Hi Ryan,

                  I have set up the rotating region. Just a couple of questions,

                   

                  Would the analysis not be different as the wind turbine is extracting energy from the air whilst the the helicopter is putting energy in to the air? Also I am unsure of how to find drag on the blade across the radius? Is it a surface goal of 'friction force' in a certain orientation? Can you use the 'force' goal to find thrust in this set up?

                   

                  My main concern about this is that I cannot find a tutorial specifically for a wind turbine which is extracting energy from the air flow rather than rotating due to an external force, ie the helicopters motor.

                   

                  Thanks for the help!