[MBDyn-users] WG: contribution to "CART"-WindTurbine example model & inconsistency in AeroDyn-12.58 interface

Pierangelo Masarati masarati at aero.polimi.it
Tue Aug 28 16:53:57 CEST 2012

On 08/13/2012 03:29 PM, Rix, Patrick wrote:
> Hi Pierangelo,
> dear users !
> After having successfully finished the structural benchmark of our rotor blade model comparing against SIMPACK and HAWC2, we now started continuing with the aerodynamic validation based on NREL's AeroDyn-12.58 library using the two-bladed "CART" wind turbine model from the MBDyn examples corner as starting point. We adapted the aerodynamic part of your model to using AeroDyn and made some first test-simulations as "warm-up" exercise to get used to AeroDyn and finally got reasonable results - but during the work also a BUG(?) in the AeroDyn interface showed up [..it's a suspicion, but we are pretty sure that there is some inconsistency in the interface as we have to put a negative(?!) wind speed in the AeroDyn input file to get matching results comparing to MBDyn's intrinsic aerodynamics and to other wind turbine codes such as Flex5. I strongly assume that it's simply a mis-orientation by 180° as not only the longitudinal wind speed has to be negative but also "left" and "ri
 ght" side
 are reversed when using full field turbulent wind files.
>   ==> Did you or any user make the same observation ? ].
> Apart from this inconsistency there also came up a few more questions which I'd like to discuss in separate threads.
> To get a better overview and not to get lost within the many reference frames inside the CART wind turbine model I made a hand-sketch (PDF) of the reference frames, which I wanted to contribute in the hope it might be useful to other users, too, when starting to investigate in the model. (see attached PDF files which are unfortunately too big for the mailing list).
> Hoping that my little drawing passes approval, I wanted to propose to put it along with the code of example model as well as some links pointing to two NREL documents, which describe the structural and geometrical details of the real turbine (and which state e.g. that the turbine runs upwind with clockwise rotation, when looking downstream on the rotor).
> CART - wind turbine DOCUMENTATION:
>      K.A. Stol,  "Geometry and Structural Properties for the Controls Advanced Research Turbine (CART) from Model Tuning", 2003,  NREL
>      http://www.nrel.gov/docs/fy04osti/32087.pdf
>      Fingersh, L.J. & Johnson, K., "Controls Advanced Research Turbine (CART) Commissioning and Baseline Data Collection", 2002, NREL
>      http://www.nrel.gov/docs/fy04osti/32087.pdf


thank you for your contribution.  The sketch is now available here 
<http://www.mbdyn.org/documentation/research/windturbine/index.html> and 
the cart models with built-in aerodynamics and with AeroDyn 12.58 will 
be part of the forthcoming release of MBDyn 1.5.0 (announced by the end 
of this week).

Sincerely, p.

Pierangelo Masarati
Associate Professor
Dipartimento di Ingegneria Aerospaziale
Politecnico di Milano

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