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Exawind / amr-wind

AMReX-based structured wind solver
https://exawind.github.io/amr-wind
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Power underestimated by OpenFAST using ALM in AMR-Wind #869

Closed wenchaoyu closed 1 year ago

wenchaoyu commented 1 year ago

Dear all,

Recently, I encounted an issue when running AMR-Wind with OpenFAST using actuator line method for a single NREL5MW turbine in a uniform inflow 8 m/s, the generator power predicted is close to 1MW in this simulation while the reference value is 1.77MW. We tried to use different epsilon values in actuator line method, we observed the power increased slightly as a function of epsilon, but still away from 1.77MW (shown in the figure below) image

Another issue we saw is the tower cannot be seen through the actuator source term, so the flow is not disturbed by the presence of tower even we have 50 forcing points on the tower image

I would like to see if you have seen these kinds of issues before? Would it be something I wrongly configurated in AMR-Wind or OpenFAST input files?

Thank you for any comments. Best regards

AMR-Wind: main version dated to 20230620 OpenFAST version: v3.4.1 and v3.5.0

tonyinme commented 1 year ago

Hi @wenchaoyu , can you please share the input files for the simulation and for the openfast turbine (.fst, elastodyn, and aerodyn input files)?

wenchaoyu commented 1 year ago

Hi @tonyinme, thank you for your reply. Please find here all the input files, and feel free if you need more informations.

Have you seen this kind of issue before ?

NREL5MW_AMRWind.tar.gz

tonyinme commented 1 year ago

Hi @wenchaoyu , when running openfast with CFD (ALM), you need to setup this flag in aeroyn to zero.

1 WakeMod - Type of wake/induction model (switch) {0=none, 1=BEMT, 2=DBEMT, 3=OLAF} [WakeMod cannot be 2 or 3 when linearizing]

I will close this issue for now. Let us know if this fixes the problem or if we need to reopen the issue.

wenchaoyu commented 1 year ago

Hi @tonyinme, thank you for this information. To confirm with you, it helps to resolve the issue on the power underestimation, now we can get the power very close to the reference power.

However, the tower is still not shown via the actuator source term, only the blade can be seen. Since we would like to investigate on the effect of the tower, it is important to make sure it is taken into account in ALM. Can you confirm if it is the case on your side? If not, am I missing some other flags in aerodyn regarding tower? (I tried some of them, but none of them can help to get the tower back.

Thanks for your help.

tonyinme commented 1 year ago

Hi @wenchaoyu , Have you checked the simulations in detail? The tower produces a small drag force, compared to the higher lift force from blades. Can you check your simulations and adjust the ranges of the forces being plotted to make sure that the tower forces are there or not? Also, can you try setting the number of tower points in the amr-wind input file to the same as openfast?

12 NumTwrNds - Number of tower nodes used in the analysis (-) [used only when TwrPotent/=0, TwrShadow/=0, TwrAero=True, or Buoyancy=True]

wenchaoyu commented 1 year ago

Hi @tonyinme,

Yes, I tried to set the number of tower points in amr-wind Actuator.TurbineFastLine.num_points_tower = 12, but still cannot see the tower via actuator source term, no matter how I adjusted the ranges of the forces being plotted (see figure below) image

and the wind speed seems not to be affected by the tower in this simulation with uniform inflow: image

And I ask this question since the tower can be seen in my naluwind simulation via actuator source term with right ranges of forces: image

wenchaoyu commented 11 months ago

Hi @tonyinme, I would like to reopen this discussion. Could you confirm if the tower can be taken into account correctly in your amr-wind simulations with turbine? Best regards

tonyinme commented 11 months ago

Yes, it can. Make sure that the number of tower points is the same in openfast and amr-wind.

On Wed, Aug 16, 2023, 2:43 AM Wenchao YU @.***> wrote:

Hi @tonyinme https://github.com/tonyinme, I would like to reopen this discussion. Could you confirm if the tower can be taken into account correctly in your amr-wind simulations with turbine? Best regards

— Reply to this email directly, view it on GitHub https://github.com/Exawind/amr-wind/issues/869#issuecomment-1680203414, or unsubscribe https://github.com/notifications/unsubscribe-auth/ACULCAPYJ5T2LT5ZXRZL2DLXVSBZVANCNFSM6AAAAAAZZ3QWAE . You are receiving this because you were mentioned.Message ID: @.***>