NREL 5MW Turbulent Grid Spacing

Hello,

We at UC Davis are using the 5 MW model for control algorithm development. Would you please recommend an appropriate grid spacing (NumGrid_Z, NumGrid_Y) in TurbSim for this model. I’m used to 5 meter spacing for GL certification but this would result in an enormous file.

Thanks,

Hi,

We have been using 31x31 grids for the 5 MW model, which gives us a little better than 5-m resolution. The files are large (72 MB), but the 5 MW turbine is a large machine.

Due to hardware memory requirements in the past, we’ve had to generate these files on a 64-bit Windows server, but I’ve recently made some algorithmic changes to TurbSim to allow us to generate these grids with 32-bit desktop PCs. If you’d like to use it, you can download the alpha version at http://wind.nrel.gov/designcodes/preprocessors/turbsim/alpha/.

Hi Bonnie,

Thank you for the information. I will look into running these wind files.

On a similar note, do you know of any studies on appropriate grid spacing? If not I think this would make for a useful research project.

Thanks,

Since Bonnie made the new version that allows dense grids, I don’t think we’ve done anything. Neil has been asking us for grids that are approximately equal to the cord length–probably the minimum cord for the blade.

This very project has been on my list for some time. Unfortunately, I haven’t yet had the time to do it.

I read this interesting post and wonder if a few years later someone might be able to make a statement regarding to the grid spacing.
I would be interested by a rule of thumb which let me get a suitable grid spacing.
Does the selected grid spacing effect the computation of the free wind at every blade station?
Is it possible that a do miss out some wind spectra?

I would also be interested on any kind of research regarding to that problem.

Best regards,

Matthias