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vertical wind profile
Up to Using openWind
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Dear
Nick,
I
got to know about OpenWind at a Seminar in Santiago de Chile two weeks ago.
Firstly, I would like to thank you for developing this tool and for enabling
such open communication which surely is a great way to assure continuous
improvement of OpenWind.
I
would like to ask you how OpenWind considers the vertical wind profile when
calculating energy yield. In Northern Chile there are many locations with a
strong nighttime inversion of the vertical wind profile, meaning that at night
the maximum wind speed often lies at about just 40 m and decreases with greater
heights. Considering that the night time winds tend to be very strong, I
believe this phenomenon has an important effect on the energy output
calculations.
To
my knowledge, WindPro does not take into account such effects ... it takes wind
speed at hub height and power curves corresponding to a standard vertical wind
profile according to IEC norm (0,05 m roughness length). Thus, for a realistic
calculation one would need to have the specific power curves which correspond
to the vertical wind profile at the site in Chile and introduce these into WindPro.
It
would be great if you could give an explanation how OpenWind works in such cases.
Thanks in advance and best regards
Tim
Hi Tim,
OpenWind does the same as WindPro and WindFarmer so far as I know. The standard way is to specify the wind speed at hub height only. No account is taken of the wind shear across the rotor disk as it is assumed to be the same as when the power curve tests were run.
The data and file structures already exist in openWind to allow what you suggest and it is something that has been on my list of things to do for a while as Meteodyn have been asking for it.
In order to get it right I will need to consult with others. At present all my time is taken with finishing up the Enterprise Edition of openWind. However, I will try to get to this by the end of this year.
Of course, if someone pays me to do it then it definitely gets done 
Nick