Hello,

After installing all the necessary modules I try to test RAFT with the provided example and I get the following message:
ImportError: /pyHAMS/pyhams/hams.cpython-39-x86_64-linux-gnu.so: undefined symbol: zgetrs

I tried it with both python 3.9 and 3.10 but this doesn't seem to be the problem.

Hi,

Thanks for creating what looks like another very useful model!

I apologize if this is a silly issue but I am struggling to write the results from the VolturnUS example to an output file as I do not have much experience with Python. Is there an existing function/command which can be added to the 'example_from_yaml.py' file to do this?

To calculate the QTFs in Nemoh V3 a linearized mooring stiffness matrix and viscous drag matrix are needed as inputs, these are primarily the outputs I want from RAFT after running 'model.analyzeCases'. Up to now I have been using MoorPY to get the linearized mooring stiffness matrix but as RAFT can calculate the linearized viscous drag matrix also it makes sense to use RAFT.

Thanks,
Tom

When running in a massively parallel way on HPC, for instance, this line can fail. It appears that there's a race condition that can get multiple processors past the L320 if statement before this line is reached, then the "if directory exists" condition changes after evaluating the if statement on L320.

Adding a keyword argument for exists_ok=True into the os.makedirs call on L320 can be used to allow this condition to be ok, I think.

Garrett pointed out the values we are using here. These look to be the nominal rather than volume-equivalent diameter for these chains. We should check all our examples and correct to volume-equivalent if needed.

I have a question regarding the definition of the rotor averaged wind speed amplitudes U(ω). In the code snippet I am attaching, a Rot variable is defined which does not use any of the spectra in the X, Y, Z directions. It is mentioned that these formulas are derived from the IEC 61400-1-2019 annex C ("Compute turbulence scale parameter Annex C3 of IEC 61400-1-2019") however said anex defines the coherence function and the PSDs in the 3 directions for the Kaimal method. Some complex math is involved in this calculation, and I would like to ask how this equation is defined if there are any sources I can look into to understand the meaning of this derived spectrum. I looked into any publications I could find using Raft, but in most cases this part was not referenced at all.

Hi Matt, Stein, and the greater RAFT team,

What is your recommended way of installing CCBlade when using RAFT as a standalone? To use the standalone CCBlade (my hypothesis)? Install WISDEM from source? From conda install wisdem? Just use WEIS and get everything together?

This is essentially the question being asked in this WISDEM issue. Feel free to post a reply back there if that is easiest.

Cheers,
Garrett

Hi,
as far as I understood RAFT performs a frequency based, potential flow analysis of the platform utilising pyHAMS. Where I can find the output files of pyHAMS, and are they in WAMIT output format, so that they can be imported in OpenFAST?

Hello,

I am trying to run the example file for the VolturnUS floater in RAFT on linux (on HPC cluster, centOS linux 7). When potModMaster value is 1 (no BEM application), the code runs properly. However, when potModMaster is switched to 0 (BEM application) then I get the following error (see attached).

Some relevant information:
-python version: 3.9
-numpy: 1.23.5. I had to downgrade from the initial version (1.24), as the np.int in the member2pnl.py is deprecated in 1.24.

Thanks a lot!

I have recently rebooted my PC and reinstalled RAFT. However, the installation seems to be unsuccessful as when I run the example_from_yaml.py i get the following error:

cd RAFT
cd examples
(raft-env) PS C:\Users\hfleh\RAFT\examples> python example_from_yaml.py
Traceback (most recent call last):
File "C:\Users\hfleh\RAFT\examples\example_from_yaml.py", line 6, in
import raft
File "c:\users\hfleh\raft\raft_init_.py", line 3, in
import raft.raft_model as model
File "c:\users\hfleh\raft\raft\raft_model.py", line 15, in
import raft.raft_fowt as fowt
File "c:\users\hfleh\raft\raft\raft_fowt.py", line 7, in
import pyhams.pyhams as ph
ModuleNotFoundError: No module named 'pyhams'
(raft-env) PS C:\Users\hfleh\RAFT\examples>`

I have cloned and setup all relevant repositories: WISDEM, MoorPy, PyHAMS, RAFT.
Can you help me?

I modeled a floater with WTG+tower on one of the columns. (similar to PPI or Technip INO15 floater.
We have used the example floater from the RAFT package (VolturnUS-S_example.yaml) and kept the turbine + tower at (X,Y) = (0, 0). Basically we translated floater column + mooring + anchor coordinates in X direction.
(all Columns have nearly same mass…meaning we would expect the weight of the turbine would result in pitch forward, but the opposite is the case).
Running RAFT we now get this weird behavior(see picture below) in steady state (no wind, no waves).

What can be cause of this? Coordinate system of RAFT and pyHAMS not matching?

Thanks in advance
Jasper Koot
Siemens Gamesa

Hi @gbarter, thanks for this nice code! By skimming through it I noticed that you have computed a couple of matrix inverses. Generally, this has bad numerical properties, as it's both slow and inaccurate. You should instead solve a linear system.

I suggest to:

• At raft_model L399 replace np.matmul(np.linalg.inv(M_tot), C_tot) with np.linalg.solve(M_tot, C_tot).
• At raft_model L540 replace np.matmul(np.linalg.inv(Z[:,:,ii]), F_tot[:,ii] ) with np.linalg.solve(Z[:,:,ii], F_tot[:,ii]).

Furthermore, if M_tot and Z are reasonably sparse, you might get an even faster solution using spsolve.

By the way, the routines from scipy.linalg might be faster than the ones from numpy on some architectures.

I've been looking into the code of the aerodynamics calculations of raft because I am trying to understand if some results on the OC4 platform I am getting are reasonable, and I believe I've stumbled on a small error in the calcAero function of the rotor.py file. In line 872, where the torque control gains are defined, in both the integral and proportional gains, the kp_tau value is used, when it should be ki_tau for the integral term and kp_tau for the proportional term. The results I am getting after correcting this are very different from the original code (for cases where wind speed is below the rated speed).

Hello,

Thank you for creating this excellent tool. I understand that it is possible to simulate shared mooring configuration with RAFT.

I was trying to run the example file for a farm configuration provided here RAFT/designs/VolturnUS-S_farm.yaml. It comes up with the following error :

I could not find the file called 'SharedMooring2.dat' in the repository. Can you please help with this.

I haven't been able to find a satisfying answer in documentation or source code regarding the attributes 'yaw_misalign' and 'wind_speed' of each case, and just wanted to check their definitions.

For 'wind_speed' - is this the wind speed at 10 m above mean sea level or at equilibrium hub height?

For 'yaw_misalign' - is this angle relative to the wind vector or to the overall coordinate system of the FOWT?

Many thanks

Hi,

In order to evaluate the feasibility of FOWTs with semi-taut mooring systems, it would be nice to be able to assess whether the connection point between the synthetic line and chain makes contact with the seabed and assess whether the loads on the anchor are purely horizontal. Does RAFT have any options for this? I saw that MoorPy has some methods to do this (getForces, getPositions, getAnchorLoads), but these all only work with MoorDyn output files, rather than RAFT simulation data. Is there anything that can be used?

Many thanks

Dear all,
I've followed all the instructions to install RAFT, and I am able to successfully run the example script in https://openraft.readthedocs.io/en/latest/starting.html using the VolturnUS-S.yaml default file.
Nonetheless, the setting for potModMaster is 1, i.e. "1=turns all potMod vars to False (no HAMS)", although some of the elements (center_column and outer_column are defined as "potMod : True".
When I change potModMaster to 0 (0=keeps all member potMod vars the same), I obtain the following error:
`Found mean offets with with surge = 0.02 m and pitch = 0.00 deg.

--------- Natural frequencies and mode shapes -------------
Mode 1 2 3 4 5 6
Fn (Hz) 0.0087 0.0087 0.0611 0.0405 0.0405 0.0150

DOF 1 -1.0000 -0.0129 0.0000 0.0003 -0.9889 -0.0000
DOF 2 0.0000 -0.9999 0.0000 -0.9889 0.0001 0.0888
DOF 3 -0.0000 -0.0000 -1.0000 -0.0000 0.0000 -0.0000
DOF 4 0.0000 -0.0006 -0.0000 0.1487 -0.0000 0.0002
DOF 5 0.0006 0.0000 0.0000 0.0000 -0.1486 0.0000
DOF 6 -0.0000 0.0001 0.0000 0.0000 -0.0000 0.9960

Of 312 generated panels, 172 were submerged and have been used in the mesh.
Of 600 generated panels, 332 were submerged and have been used in the mesh.
Of 600 generated panels, 332 were submerged and have been used in the mesh.
Of 600 generated panels, 332 were submerged and have been used in the mesh.
Traceback (most recent call last):

File "C:\Users\mauri\anaconda3\envs\spyder-env-WSDM\lib\site-packages\spyder_kernels\py3compat.py", line 356, in compat_exec
exec(code, globals, locals)

File "c:\users\mauri\onedrive_maurizio_company\sandbox\raft\raft_example.py", line 27, in
model.analyzeCases(display=1)

File "C:\Users\mauri\anaconda3\envs\spyder-env-WSDM\lib\site-packages\raft\raft_model.py", line 236, in analyzeCases
fowt.calcBEM(meshDir=meshDir)

File "C:\Users\mauri\anaconda3\envs\spyder-env-WSDM\lib\site-packages\raft\raft_fowt.py", line 391, in calcBEM
ph.run_hams(meshDir)

File "C:\Users\mauri\anaconda3\envs\spyder-env-WSDM\lib\site-packages\pyhams\pyhams.py", line 404, in run_hams
sub.run([f'{hamsPath}'])

File "C:\Users\mauri\anaconda3\envs\spyder-env-WSDM\lib\subprocess.py", line 503, in run
with Popen(*popenargs, **kwargs) as process:

File "C:\Users\mauri\anaconda3\envs\spyder-env-WSDM\lib\site-packages\spyder_kernels\customize\spydercustomize.py", line 109, in init
super(SubprocessPopen, self).init(*args, **kwargs)

File "C:\Users\mauri\anaconda3\envs\spyder-env-WSDM\lib\subprocess.py", line 971, in init
self._execute_child(args, executable, preexec_fn, close_fds,

File "C:\Users\mauri\anaconda3\envs\spyder-env-WSDM\lib\subprocess.py", line 1440, in _execute_child
hp, ht, pid, tid = _winapi.CreateProcess(executable, args,

FileNotFoundError: [WinError 2] The system cannot find the file specified`

The error is:
`
(base) MacBook-Air-2:xxx$ conda env create -f raft-env.yaml
Collecting package metadata (repodata.json): done
Solving environment: failed

ResolvePackageNotFound:

• m2w64-headers-git==5.0.0.4636.c0ad18a=2
• m2w64-pkg-config==0.29.1=2
• setuptools==68.0.0=py39haa95532_0
• m2w64-gcc-libgfortran==5.3.0=6
• ca-certificates==2023.05.30=haa95532_0
• mkl==2023.1.0=h8bd8f75_46356
• intel-openmp==2023.1.0=h59b6b97_46319
• m2w64-libiconv==1.14=6
• msys2-conda-epoch==20160418=1
• m2w64-bzip2==1.0.6=6
• pyhams==1.2.1=py39hab42cac_0
• m2w64-gcc==5.3.0=6
• m2w64-tools-git==5.0.0.4592.90b8472=2
• m2w64-libwinpthread-git==5.0.0.4634.697f757=2
• libflang==5.0.0=h6538335_20180525
• libblas==3.9.0=1_h8933c1f_netlib
• openmp==5.0.0=vc14_1
• m2w64-libmangle-git==5.0.0.4509.2e5a9a2=2
• sqlite==3.41.2=h2bbff1b_0
• openssl==3.0.10=h2bbff1b_0
• m2w64-gcc-ada==5.3.0=6
• vc==14.2=h21ff451_1
• vs2015_runtime==14.27.29016=h5e58377_2
• m2w64-mpfr==3.1.4=4
• m2w64-binutils==2.25.1=5
• numpy==1.25.0=py39h055cbcc_0
• m2w64-gcc-libs==5.3.0=7
• mkl_random==1.2.2=py39hf11a4ad_1
• m2w64-mpc==1.0.3=3
• libopenblas==0.3.21=pthreads_h02691f0_2
• openblas==0.3.21=pthreads_ha35c500_2
• mkl-service==2.4.0=py39h2bbff1b_1
• wheel==0.38.4=py39haa95532_0
• m2w64-gcc-libs-core==5.3.0=7
• m2w64-gcc-objc==5.3.0=6
• tbb==2021.8.0=h59b6b97_0
• pip==23.2.1=py39haa95532_0
• m2w64-zlib==1.2.8=10
• m2w64-windows-default-manifest==6.4=3
• m2w64-toolchain==5.3.0=7
• m2w64-winpthreads-git==5.0.0.4634.697f757=2
• numpy-base==1.25.0=py39h65a83cf_0
• libpython==2.1=py39haa95532_0
• m2w64-isl==0.16.1=2
• m2w64-crt-git==5.0.0.4636.2595836=2
• m2w64-gmp==6.1.0=2
• m2w64-gcc-fortran==5.3.0=6
• python==3.9.17=h1aa4202_0
• m2w64-make==4.1.2351.a80a8b8=2
• liblapack==3.9.0=5_hd5c7e75_netlib
• mkl_fft==1.3.6=py39hf11a4ad_1
  `
  Is this because the raft-env.yaml file only works for the linux system?

Thanks,
Ying