Wake width plot quesiton

[lucamholden-arch]

Hi, ive been running simulations to find out how platform motions affect the wake and was wondering the best way to record values such as the wakes width and the wake trajectory ( maybe center of wake position ) in fastfarm. I have tried to use the VTK files but that doesnt seem to effective. Is there any values or outputs i can add to the simulations that will help me? or do you have any advice that can help me ?
Thanks for your continued support

[jjonkman]

Dear @lucamholden-arch,

For the VTK output, you can extract wake-related quantities such as the trajectory of the wake center and the wake width as a function of downstream distance through post-processing tools such as SAMWICH Toolbox: https://ewquon.github.io/waketracking/.

FAST.Farm also provides direct outputs of these quantities on a per-wake (per-turbine) basis through parameters available in the FAST.Farm OutList, including WkPosδTαDγ for wake center position and WkDiamTαDγ for wake diameter, as described in the online FAST.Farm documentation on readthedocs: https://openfast.readthedocs.io/en/main/source/user/fast.farm/AppendixC.html.

Best regards,

[lucamholden-arch]

Thanks I have since plotted them, however my wake width / diameter seems to be confined around 126m. I change the moddiam from 1 to 4 but still looks like it’s around 126 no matter the change of wind and wave inputs from 100m to 900m behind the turbine. Are there any other inputs that confine this diameter that I may be missing ?

[jjonkman]

Dear @lucamholden-arch,

I would expect Mod_WakeDiam to have some impact on the wake diameter computed by FAST.Farm. C_WakeDiam should also have an impact for Mod_WakeDiam = 2, 3, or 4. Can you share a plot of what you are seeing? Also, which Mod_Wake are you using?

Best regards,