CACTUS GUST SIMULATION

[sakibsadman7]

CACTUS GUST SIMULATION

[xflow-ian]

I have also been having issues with the gust simulation. By monitoring the fieldData output, I am able to observe that setting igust = 1 overrides the free stream to be uniform, even when slex is non zero. I have tried a variety of physically relvant values of gustamp, gusttime, and gustX0 , but am not able to observe the gust in the free stream or induced velocity fields.

[whophil]

It looks like shear is ignored when igust = 1.

After some experimentation, I was able to see gust effects in the exported field data. Can you share the gust parameters you are using?

[xflow-ian]

Glad to hear it is working for you! My gust parameters were gustamp = 2, gusttime = 0.5, gustX0 = -5. The gust starting location, gustX0, was chosen to be upstream of the rotor and my gusttime corresponded to half a rotation of the turbine. The nominal free stream velocity was 8 m/s so I would have expected a 2 m/s gust to be noticeable.

For my field data, I was recording 20 points vertically spaced at the X-Z position 2 diameters upstream of the rotor.

[xflow-ian]

Could you share your parameters so I can try to recreate them on my machine?

[whophil]

I've attached a modified TestCase1/TestHAWT.in which applies a gust and also samples field data every timestep at the (0, 0, 0) using the Probe feature.

Here is a plot of Ufs/Uinf from the probe data.

TestCaseGust.zip
Unzip this into [CACTUS source]/test/ to run.

[xflow-ian]

Thanks for sharing this example. I was able to replicate it on my machine. Additionally, I was able to change the gust parameters and have the gust profile change as expected.

[whophil]

Great! The confusing part for me was the gusttime parameter, which needed to be much longer than what I had originally set when I was just messing around. Closing this issue.