NREL 5MW Turbulent Grid Spacing

Wind & Water Inflow Turbulence
1

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,

2

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 [url]National Wind Technology Center's Information Portal | Wind Research | NREL.

3

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,

4

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.

5

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

6

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