wind turbine blade design

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Hi,

What is the best way to design the root region of a wind turbine blade (for a small model turbine: 0.7m diameter, Re ~ 10,000)? So far we've selected our airfoil and calculated the chord lengths (proprtional to 1/R) but can't find any mathematics on the root region. At what point should it cease to follow the 1/r relationship and should this be a fairly abrupt change or a curved gradual change?

Furthermore, what is teh best way to calculate the bending stresses at the root

Thanks for any help

minger

We typically start with an analysis like this with an initial concept. We then find the stresses and from there determine what needs to be changed to account for the stresses (thermal, bending, shear, etc).

Since you will typically be encountering mostly normal stresses (from radial centripital force, and bending from wind load), you can most likely decide on a width needed, and then just ensure that's its smooth enough of a blend into the hub as to not create large stress concentratiosn.