The questions about HyDrodyn WaveMod=6

Dear all
I am using WaceMod = 6 in Hydrodyn for my calculations.
In the process of using it, I found that I need to provide input files containing Vxi, Vyi, Vzi, Axi, Ayi, Azi, DynP, Elev.
My questions are:

  1. I didn’t find the file for water depth input. Where is the file for water depth input. The Hydrodyn file only let me input the parameter file and horizontal coordinate position, but there should be parameter of different water depth for calculating the floating body force, right?
  2. How to select the coordinate points (up to 9 points) in the input file to make the structure calculation more accurate?
    Thank you!
    Shunhang Lu

Dear @Shunhang.Lu,

Here are my answers to your questions, which I presume were in reference to WaveMod = 6 (not WaceMod):

  1. With WaveMod = 6, the columns in each of the wave velocity, wave acceleration, and dynamic pressure files correspond to the internal HydroDyn analysis nodes–as determined by the strip-theory member input definitions–corresponding exactly those written to the HydroDyn summary file.
  2. Presumably you are referring to HydroDyn inputs NWaveElev, WaveElevxi, and WaveElevzi. You can set these arbitrarily at up to 9 locations; they will not impact the solution accuracy. It is the number of strip-theory hydrodynamic analysis nodes that will impact the solution accuracy, not the number of wave elevation outputs.

Best regards,

Dear @Jason.Jonkman
Thank you for answering my question. First of all, I’m sorry for the spelling mistake.

  1. With WaveMod=6, what I understand is that the number of columns in the input file is related to NWaveElev. In my understanding, if NWaveElev=5, then the input file .Vxi, .Vyi, .Vzi, .Axi, .Ayi, .Azi, .DynP each has five columns of data. But in your answer, it means that if n computing nodes are set up in strip-theory, then the input file has n columns, and the data of each column corresponds to different water depth positions in turn, right?
    2.If the NwaveElev is greater than one, do I need to enter multiple file names on the WvKinFile line of the HydroDyn file? What’s the distinction between different file names, spaces or commas? Multiple quoted strings separated by spaces?
    3.Can the location of the computing node of strip-theory be modified by the user? Could you please tell me how to modify the computing node of strip-theory? Or can you tell me where there are WaveMod=6 tutorials so I can study them.
    As a beginner, I’m sorry to ask so many basic questions. Thank you again for your answer.

I learn the use of the “WaveMod = 6” is in “ Input Files — OpenFAST v3.3.0 documentation”. But I seem to have misunderstood.

Dear @Shunhang.Lu,

Here are my responses:

  1. The number of columns in the .Elev file is NWaveElev. The number of columns in the .Vxi, .Vyi, .Vzi, .Axi, .Ayi, .Azi, and .DynP files is the number of internal hydrodynamic analysis nodes.
  2. No, there is only one .Elev file, with the number of columns equaling NWaveElev.
  3. Yes. The internal hydrodynamic analysis nodes are dictated by the joints, members, and member discretization (NDivSize) in the definition of the strip-theory members. The exact location of each internal hydrodynamic analysis node is given in the HydroDyn summary file.

Best regards,

Dear @Jason.Jonkman
Thank you very much for your answer, now I figure out the format of the input file.
Best regards