search

OpenFAST / openfast

Main repository for the NREL-supported OpenFAST whole-turbine and FAST.Farm wind farm simulation codes.
http://openfast.readthedocs.io
Apache License 2.0
695 stars 459 forks source link

Wave kinematics output in HydroDyn #2473

Open Quesion opened 1 month ago

Quesion commented 1 month ago

Dear all: Recently, I have been using HydroDyn in MW_OC3Mnpl_DLL_WTurb_WavesIrr to generate wave loads. When I checked the results, I noticed that at the bottom of the pile, specifically at a water depth of 20 meters, the wave speed is 0 in three directions. This does not align with the values calculated using linear Airy wave theory. I would like to know if there is an issue with how I defined the input file or the output, or if there could be another reason. Below are my HydroDyn input file and the output results. Best regards 5MW_OC3Mnpl_DLL_WTurb_WavesIrr.xlsx NRELOffshrBsline5MW_OC3Monopile_HydroDyn.txt

jjonkman commented 1 month ago

Dear @Quesion,

In this HydroDyn example for the OC3-monopile, there are 2 joints and 1 member in the strip-theory solution, where the lower joint is located just below the seabed (JointZi = -20.0001 m) and the upper joint is above MSL and wave stretching is not enabled (JointZi = 10 m). As such, these joints do not lie within the water domain, and HydroDyn will output zeros for the wave kinematics at these locations. if you want to output the wave kinematics within the domain, add joints or select node locations for the member outputs within the water domain (between Zi = -20 and 0 m).

Best regards,

Quesion commented 1 month ago

Dear @jjonkman , Thank you for your reply! Now I can obtain the desired output. Besides that, I have another question. I know that in AeroDyn, it is possible to use Nodal Outputs to output data for all blade nodes. Is there a similar output mode for wind loads on the tower and wave loads in HydroDyn? Best regards,

jjonkman commented 1 month ago

Dear @Quesion,

No, AeroDyn does not support nodal-style outputs for the tower and HydroDyn does not support nodal-style outputs for the substructure.

Best regards,