OpenFAST operational questions.

[HiHabi]

Hi, Dear @jjonkman

I have a few questions for modifying some items from the reg_tests file, for instance：5MW_OC4Jckt_DLL_WTurb_WavesIrr_MGrowth (the following questions will basically be files inside this folder, the rest will be the 5MW-baseline folder for input files mentioned in the previous .fst file)

1. I have succeed to modify the inputs of TurbSim by changing the .inp files (90m_12mps_twr.inp), and the results seem to be quite decent as it output the files of .bts & .dat, could it be seen as successfully for the TurbSim operation? (All operations above were done in the 5MW_baseline folder.)
2. After finishing the simulations with TurbSim, I’d tried to modify the InflowWind input files option from 5MW_OC4Jckt_DLL_WTurb_WavesIrr_MGrowth.fst, however it shows the fatal error as following: {FAST_InitializeAll: InflowWind_Init: InflowWind_ParseInputFileInfo:ParseLoVar:

   A fatal error occurred when parsing data from ".../5MW_Baseline/90m_12mps_twr.dat". The variable "Echo" was not found on line #6.} It seems that I will have to change the input file of “NRELOffshrBsline5MW_InflowWind_12mps.dat” (such as “NRELOffshrBsline5MW_InflowWind_12mps.inp”) to input TurbSim and generating different Wind Farm simulations, any ideas where could I found such file or fix the problem by modifying the 90m_12mps_twr.inp/ .dat file?

3. When executing the openfast.exe with “5MW_OC4Jckt_DLL_WTurb_WavesIrr_MGrowth.fst file”, it show some unsatisfactory results from the model of Elastodyn, Aerodyn15 and Subdyn, I shall post the entire cmd windows as follow:

any ideas or reference that I may look for? and how may I solve the warning errors? Thanks for you patients on my ignorance on operating the OpenFAST program.

Best regards,

[jjonkman]

Dear @HiHabi,

Here are my responses:

1. You haven't shared any details to comment on, but it sounds like you are running TurbSim correctly.
2. From the error it sounds like you have set InflowFile in the OpenFAST primary (.fst) input file to the name of the TurbSim input file in place of the InflowWind input file. You should set InflowFile in the OpenFAST primary input file to the name of the InflowWind input file, and then in the InflowWind input file, you should select WindType = 3 to use TurbSim format and set FileName_BTS to the name of the TurbSim output file.
3. It looks like you are simulating a condition with a mean wind speed of 40 m/s. This is above the operational wind speed range of the NREL 5-MW baseline turbine, so, if you have not already, you should set up your model to run in idling mode with the controller disabled, blades pitched to feather, and aerodynamic induction (wake) disabled.

Best regards,

[HiHabi]

Dear @jjonkman , thanks for your reply

On responses 2., I'm wondering should I operate the InflowWind to get the InflowFile such as “NRELOffshrBsline5MW_InflowWind_12mps.dat” to continue on openfast primary file(.fst), but how should I generate such file by InflowWind as I hadn't seen any module to process the needs. (and I'm assuming to input the file such as 90m_12mps_twr.dat from TurbSim output into InflowWind module, then replace the original ones in the openfast primary file(.fst) ...? Not sure if my ideas were correct, please feel free to guide)

for the 3. point, I did not notice the maximum wind speed, apologies for that, and should I modify the InflowWind mean speed with around 25m/s? It's has been quite confusing from putting the TurbSim output file into InflowWind/ Openfast to continue on next steps. However I'm wondering if I modify the input options in different .dat files, will that cause influence to the interface reaction forces a lot, as I will need to extract the reaction forces on transition pieces into abaqus from further studies,

above are my questions, thank for you time and looking for the responses Best regards,

[jjonkman]

Dear @HiHabi,

The InflowWind file _NRELOffshrBsline5MW_InflowWind12mps.dat used by the NREL 5-MW baseline wind turbine atop the OC4-jacket r-test is available here: NRELOffshrBsline5MW_InflowWind_12mps.dat. I've already explained how to modify this file.

It is typical to run OpenFAST for many conditions, e.g., by running separate simulations at different mean wind speeds, which you can use to calculate reaction loads at different conditions. The turbine would operate for wind speeds between cut-in and cut-out and be idling for lower or higher wind speeds.

Best regards,

[HiHabi]

Dear @jjonkman

If I would like to simulate different wind farm condition, to generate different interface reational forces result for further studies purpose, it appears that I should modify the "Wind/90m_12mps_twr.inp" with TurbSim to generate different result, which is "Wind/90m_12mps_twr.bts", then operating the OpenFAST primary file(.fst). Supposingly I could complete the OpenFAST program as expected...?

Best regards,

[jjonkman]

Yes.