Simulating the parked turbine

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Jason.Jonkman
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Re: Simulating the parked turbine

Postby Jason.Jonkman » Mon May 04, 2020 9:32 am

Dear Chenxu.Zhao,

Just a few comments:
  • Do you mean that you are looking at the tower-base fore-aft moment, i.e., moment driven by fore-aft forces?
  • Is your simulation with steady wind and in steady state? Otherwise, the solution is likely oscillatory and effect by inertia terms.
  • How is your gravity-induced moment calculated and does it include the effect of tower and blade deflection?
  • Are you considering direct aerodynamic loading on the tower, which will also contribute to the moment?
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

Chenxu.Zhao
Posts: 11
Joined: Mon May 20, 2019 4:36 am
Organization: Chongqing University
Location: China

Re: Simulating the parked turbine

Postby Chenxu.Zhao » Mon May 04, 2020 7:34 pm

Dear Jason

Thanks for your reply.

Here are my answers.

1.Yes, the tower-base fore-aft moment, is driven by fore-aft forces
2.My simulation is with turbulence wind. I set analysis time to 630s, I think it is in steady state. And I feel in mean bending moment,the inertia terms has no contribution.
3.When I calculate gravity-induced moment,I set the steady wind velocity at hub to 0.01m/s. The tower and blade DOFs are set to ‘ture’. Under such conditions, I take the tower bending moment as gravity-induced moment. It doesn’t include the effect of tower and blade deflection in turbulence wind.
4.When I calculate the side-side moment, the wind load on the tower (F=0.5*ρ*U^2*CL*A) should be 0.

Best regards,
Chenxu Zhao

Jason.Jonkman
Posts: 4862
Joined: Thu Nov 03, 2005 4:38 pm
Location: Boulder, CO
Contact:

Re: Simulating the parked turbine

Postby Jason.Jonkman » Tue May 05, 2020 7:03 am

Dear Chenxu.Zhao,

Here are my responses.
  • In your post dated May 03, you said you were using the side-to-side moment, but I gather based on your posted dated May 04 that are actually using the fore-aft moment.
  • I agree that the inertia terms will not contribute to the mean; I did not realize you were talking about means.
  • The rotor-thrust force will also induce tower and blade deflection that will change the mean gravity-induced moment; this could be the reason for the discrepancy you noted.
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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