Search found 51 matches

by Akheel.Kodambiyakamkizhakkakam
Thu Nov 19, 2020 9:56 am
Forum: Structural Analysis
Topic: NREL 5MW OC3-Hywind (Test 24) Questions
Replies: 78
Views: 13245

Re: NREL 5MW OC3-Hywind (Test 24) Questions

Dear Sir,
Is there any limit for mass ratio, Stiffness, Damping of TMD in nacelle?
by Akheel.Kodambiyakamkizhakkakam
Thu Nov 19, 2020 9:54 am
Forum: Structural Analysis
Topic: NREL 5MW OC3-Hywind (Test 24) Questions
Replies: 78
Views: 13245

Re: NREL 5MW OC3-Hywind (Test 24) Questions

Dear Sir,
The warning was found to occur at about 600 sec
by Akheel.Kodambiyakamkizhakkakam
Thu Nov 19, 2020 8:43 am
Forum: Structural Analysis
Topic: NREL 5MW OC3-Hywind (Test 24) Questions
Replies: 78
Views: 13245

Re: NREL 5MW OC3-Hywind (Test 24) Questions

Dear Sir, I tried to simulate load case 5.3 of 'Offshore Code Comparison Collaboration (OC3) for IEA Task 23 Offshore Wind Technology and Deployment' J.Jonkman, 2010. I got an error message regarding Mach Number exceeding 0.3. Initial Conditions such as Rotor Speed = 12.1 and Blade Pitch = 14.92 wer...
by Akheel.Kodambiyakamkizhakkakam
Thu Nov 19, 2020 8:23 am
Forum: Structural Analysis
Topic: NREL 5MW OC3-Hywind (Test 24) Questions
Replies: 78
Views: 13245

Re: NREL 5MW OC3-Hywind (Test 24) Questions

Dear Sir, The steady state response was matching well. I need a clarification regarding the second statement of your previous message, that if I am unaware of the expected initial pitch or surge and input some random value, Will the final result be wrong? Secondly, In the load case 5.1, I tried to e...
by Akheel.Kodambiyakamkizhakkakam
Wed Nov 18, 2020 3:12 am
Forum: Structural Analysis
Topic: NREL 5MW OC3-Hywind (Test 24) Questions
Replies: 78
Views: 13245

Re: NREL 5MW OC3-Hywind (Test 24) Questions

Dear Sir, I tried to simulate load case 5.1 in Offshore Code Comparison Collaboration (OC3) for IEA Task 23 Offshore Wind Technology and Deployment, J. Jonkman, 2010. The response I obtained in Surge was not matching. The input conditions were as follows: 1. NRELOffshrBsline5MW_InflowWind_12mps: Win...
by Akheel.Kodambiyakamkizhakkakam
Tue Nov 17, 2020 9:51 am
Forum: Structural Analysis
Topic: NREL 5MW OC3-Hywind (Test 24) Questions
Replies: 78
Views: 13245

Re: NREL 5MW OC3-Hywind (Test 24) Questions

Dear Sir, Thank you for the information. Here are some queries regarding FAST theory. 1. How does FAST compute the loads in case of spar platform. 2. Can Morison theory be used for calculating heave forces. If not which method is used. (My understanding is Morison equation can be used to calculate h...
by Akheel.Kodambiyakamkizhakkakam
Tue Nov 17, 2020 7:23 am
Forum: Computer-Aided Engineering Software Tools
Topic: Question about using TMD in nacelle
Replies: 18
Views: 2451

Re: Question about using TMD in nacelle

Dear Sir, The problem I am facing currently is that the response under the action of wind and wave is not exactly matching. I have input only the basic data that are available from the paper. If you could suggest a paper which you are familiar with, You will be able to correct me. That is why I aske...
by Akheel.Kodambiyakamkizhakkakam
Tue Nov 17, 2020 12:19 am
Forum: Computer-Aided Engineering Software Tools
Topic: Question about using TMD in nacelle
Replies: 18
Views: 2451

Re: Question about using TMD in nacelle

Jason.Jonkman wrote:Dear Akheel,

I'm not familiar with the paper you refer to, and so, cannot comment on that.

Best regards,

Dear Sir,
Since you are not familiar with it, can you suggest some paper so as to compare the responses.
by Akheel.Kodambiyakamkizhakkakam
Mon Nov 16, 2020 8:40 pm
Forum: Computer-Aided Engineering Software Tools
Topic: Question about using TMD in nacelle
Replies: 18
Views: 2451

Re: Question about using TMD in nacelle

Dear Akheel, I meant do any of the OpenFAST outputs change when you enable the TMD? For example, given the nacelle TMD mass of 10470 kg, I would expect the tower-top vertical force (YawBrFzn) to increase by about 103 kN relative to the simulation without the TMD enabled. Do you see that? I would ex...
by Akheel.Kodambiyakamkizhakkakam
Mon Nov 16, 2020 10:23 am
Forum: Computer-Aided Engineering Software Tools
Topic: Question about using TMD in nacelle
Replies: 18
Views: 2451

Re: Question about using TMD in nacelle

Dear Sir, This message is regarding Q3 of my previous message. What I meant was, I need to learn how to simulate the response of OC3 spar under wind and wave loads. With the input data in the paper (Yang e.al), I did not get the exact response as available in the paper. So Do I need to make changes ...
by Akheel.Kodambiyakamkizhakkakam
Mon Nov 16, 2020 9:39 am
Forum: Structural Analysis
Topic: NREL 5MW OC3-Hywind (Test 24) Questions
Replies: 78
Views: 13245

Re: NREL 5MW OC3-Hywind (Test 24) Questions

Dear Sir,
1. What is meant by tower strike.
2. I set initial rotor speed to 12.1 rpm, blade pitch = 0 (default value). The rotor speed was changed as I have noticed Unsteady Aerodynamics got switched off when rotor speed = 0 (Default case)
by Akheel.Kodambiyakamkizhakkakam
Mon Nov 16, 2020 9:30 am
Forum: Computer-Aided Engineering Software Tools
Topic: Question about using TMD in nacelle
Replies: 18
Views: 2451

Re: Question about using TMD in nacelle

Dear Sir, I could not find any YawBrFzn in mu output file. Only YawBrFxt YawBrFyt YawBrFzt are there. How to get 'YawBrFzn' in output file? I need more insight into following aspects 1. How to enable TMD in both nacelle and tower If they have different properties like stop position, stiffness, mass ...
by Akheel.Kodambiyakamkizhakkakam
Mon Nov 16, 2020 8:48 am
Forum: Computer-Aided Engineering Software Tools
Topic: Question about using TMD in nacelle
Replies: 18
Views: 2451

Re: Question about using TMD in nacelle

Dear Sir,
Can I know what exactly did you mean by effect from output channel?
by Akheel.Kodambiyakamkizhakkakam
Sun Nov 15, 2020 8:48 am
Forum: Computer-Aided Engineering Software Tools
Topic: Question about using TMD in nacelle
Replies: 18
Views: 2451

Re: Question about using TMD in nacelle

Dear Sir, I am trying to simulate spar with TMD in nacelle. The CompNTMD in 'NRELOffshrBsline5MW_OC3Hywind_ServoDyn' file is set true and the file name is given (all other parameters kept unaltered). In 'NRELOffshrBsline5MW_ServoDyn_TMD' file, the following changes were made(all other kept unaltered...
by Akheel.Kodambiyakamkizhakkakam
Fri Nov 13, 2020 10:48 pm
Forum: Structural Analysis
Topic: NREL 5MW OC3-Hywind (Test 24) Questions
Replies: 78
Views: 13245

Re: NREL 5MW OC3-Hywind (Test 24) Questions

Dear Sir, Thank you for the response. I have received some warnings during simulation at different load cases: Case 1: Wind Speed = 18, Turbulence intensity = 0.15, Significant avg height = 4.0, Spectral Period = 15 Warning : FAST_Solution:CalcOutputs_And_SolveForInputs:SolveOption2:AD_CalcOutput:BE...

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