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Varying strut aerofoil along struth length for VAWT
Hello everyone,
Does someone know if it is possible to vary the strut aerofoil along its length for a VAWT. For example, close to the tower you want to use a circular aerofoil for mechanical stiffness, but further away a more aerodynamic aerofoil like the NACA 0028 is more favourable.
Uptill now, I don’t find it how to implement this in QBlade. Can someone help me?
Kind regards,
Brecht Timmerman
Hi Brecht,
thats unfortunately not possible, struts can only have a single airfoil. As a workaround you could try to construct multiple struts with different airfoils and try to place them so that they resemble a single strut. For aerodynamic only simulations this should work!
BR,
David
Dear Dr. David,
It is already clear to me that it is not possible to create a variable strut cross section along its length by the VAWT blade design module.
However, if I make a variable strut by the HAWT blade design module (see Variable strut.png) and use the QFEM tool to make a structural file of this strut, do you think it is possible that a strut with constant cross section made in the VAWT blade design module will use the structural properties if I use the structural file (made by QFEM) in the Turbine module of the VAWT Turbine design module?
Kind regards,
Brecht
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Hi Brecht,
yes, thats possible. The structural beam properties can be defined completely independed from the aerodynamic definitions.
BR,
David
Hi Dr. David,
Thanks for your respons.
As an additional question, are the output forces acting on the blades and struts obtained after simulation not a bit wrong (as the aerodynamic forces will depend on the dimensions and shape of the blades and struts)?
As an example: if I use in the VAWT design mode a fixed cross-section for the strut (as it is not possible to create a varying cross-section for the strut) but in the structural file I use properties for a varying strut (see previous message), then the aerydynamic results are based on the fixed cross-section strut and these will then be used for obtaining the structural results (forces, moments, …) …
Kind regards,
Brecht
Hi Brecht,
in general the structural porperties of a blade don’t necessarily depend on its outer shape. So the aerodynamic definition and structural definition are somewhat independent. The main forces that act on an aeroelastic blade definition are aerodynamic lift, drag and moment (from the aerodynamic blade definition) and gravitational, inertia and elastic forces (from the structural blade definition).
BR,
David
Oke thanks for your respons!
