Turbsim

[sffgd]

Hello everyone，
If I want to use user-defined wind spectra and spatial correlation functions in Turbsim to generate wind files, do I need to change the source code? Or just modify the parameters in the.inp file, such as Meteorological Boundary Conditions (TurbModel="USRINP", UserFile inputs for user-defined spectra).
Best wishes

[sffgd]

I would like to add custom wind spectra and spatial coherence functions (attachment)

[jjonkman]

Dear @sffgd,

If you want to specify your own wind turbulence spectra, you can do that through input files. Set TurbModel = "USRINP" and define your own spectra via the UserFile.

If you want to change the formulation of the spatial coherence model to be different than the "GENERAL" formulation implemented in TurbSim involving the coherence decrement (a), offset parameter (b), and coherence exponent (CohExp), you'd have to modify the TurbSim source code.

Best regards,

[sffgd]

Dear @jjonkman，

Is it feasible to change only the user-defined wind spectrum without changing the spatial correlation function?

[jjonkman]

Dear @sffgd,

Yes. You can set TurbModel = "USRINP" to define your own velocity spectrum together with one of the built-in spatial coherence functions such as SCMod1 = SCMod2 = SCMod3 = "IEC", "GENERAL", or "NONE".

Best regards,

[sffgd]

Dear @jjonkman，

Thank you for your reply! But when I modify the User-Defined Spectra file, I set NumUSRf=20000, SpecScale1, 2,3 =1. Although the four wind spectra (①, ②, ④, ⑤) in the figure above are known, I do not know how to calculate u-component PSD, v-component PSD, and w-component PSD. Is there any way I can be helped？

[sffgd]

[jjonkman]

Dear @sffgd,

I'm not sure I fully understand your equations (e.g., I'm not sure what z is; n and f seem to refer to the same variable, and I would think S_u would be a function of f, not u). Regardless, presumably S_u(f) is the one-sided velocity spectrum (PSD) that needs to be specified within TurbSim's user-defined spectra input file. That is, you should multiply the right-hand side of the spectra equations by sigma^2/f to get S_u(f). Likewise for v and w, if you have equations for those spectra.

Best regards,

[sffgd]

Dear @jjonkman，
Yes，I agree with “That is, you should multiply the right-hand side of the spectra equations by sigma^2/f to get S_u(f). Likewise for v and w, if you have equations for those spectra.”, and successfully generated the wind field, thank you very much for your answer!