Your browser is no longer supported

For the best possible experience using our website we recommend you upgrade to a newer version or another browser.

Your browser appears to have cookies disabled. For the best experience of this website, please enable cookies in your browser

We'll assume we have your consent to use cookies, for example so you won't need to log in each time you visit our site.
Learn more

Hollow argument?

Letters

Hugh Burn asks why wind turbines cannot comprise hollow hemispheres rotating in a horizontal plane, like large anemometers (NCE last week).

Conventional rbines transmit a constant stress to the pylon at any given wind speed.

Unless there is a significant difference in wind speed between the lower and upper extremities of the blades, the horizontal forces do not vary as the blades rotate.

A hemispheric cup turbine, or one based on aerofoil section blades which was proposed some years ago, presents an ever-changing profile to the wind. This causes variations in stress according to the orientation of the rotor at any instant in time, and in turn leads to cyclic loading and consequent oscillation of the pylon. I believe that is why the aerofoil design never got beyond the prototype stage.

Paul Hayward (M), Rowan House, Viewlands, Silkstone Common, Barnsley, S75 4QP

Have your say

You must sign in to make a comment

Please remember that the submission of any material is governed by our Terms and Conditions and by submitting material you confirm your agreement to these Terms and Conditions. Please note comments made online may also be published in the print edition of New Civil Engineer. Links may be included in your comments but HTML is not permitted.