Tower top tilt moment and Tower bottom side-side moment looking strange

Discuss theory and modeling of wind-turbine structures.

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Jason.Jonkman
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Re: Tower top tilt moment and Tower bottom side-side moment looking strange

Postby Jason.Jonkman » Wed Feb 03, 2021 6:53 am

Dear Vishal,

I meant that the desired shear is directly specified in the input file(s). It sounds like you've set a power-low law shear exponent of 0.2 in TurbSim, presumably based on a reference height of hub height. Have you set the same shear profile (exponent, reference height) for the steady wind simulations?

Best regards,
Jason Jonkman, Ph.D.
Senior Engineer | National Wind Technology Center (NWTC)

National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway | Golden, CO 80401
+1 (303) 384 – 7026 | Fax: +1 (303) 384 – 6901
nwtc.nrel.gov

Vishal.Sairam
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Organization: Power Curve ApS
Location: Denmark

Re: Tower top tilt moment and Tower bottom side-side moment looking strange

Postby Vishal.Sairam » Thu Feb 04, 2021 2:17 am

Dear Jason,

The power law exponent was actually 0 for the steady state simulations but the hub height was the same. I will resimulate steady state files with 0.2 power law exponent and make the same comparison again.

Best regards,
Vishal

Vishal.Sairam
Posts: 37
Joined: Mon Aug 10, 2020 7:50 am
Organization: Power Curve ApS
Location: Denmark

Re: Tower top tilt moment and Tower bottom side-side moment looking strange

Postby Vishal.Sairam » Thu Feb 04, 2021 3:40 am

Dear Jason,

I re-ran the steady state simulations with a power law exponent of 0.2 and plotted the mean values against the mean values for turbulent wind simulations at 0 yaw.

Steady and Turbulent Comparison.PNG
Steady and Turbulent Comparison.PNG (270.39 KiB) Viewed 319 times


It is the shear that is causing uneven loading over the rotor.

Best regards,
Vishal

Jason.Jonkman
Posts: 5762
Joined: Thu Nov 03, 2005 4:38 pm
Location: Boulder, CO
Contact:

Re: Tower top tilt moment and Tower bottom side-side moment looking strange

Postby Jason.Jonkman » Thu Feb 04, 2021 7:05 am

Dear Vishal,

Just as I expected; thanks for confirming!

Best regards,
Jason Jonkman, Ph.D.
Senior Engineer | National Wind Technology Center (NWTC)

National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway | Golden, CO 80401
+1 (303) 384 – 7026 | Fax: +1 (303) 384 – 6901
nwtc.nrel.gov


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