CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > REEF3D

Reproducing numerical simulations

Register Blogs Members List Search Today's Posts Mark Forums Read

Like Tree2Likes
  • 1 Post By harenaobsidet
  • 1 Post By Chalwwz

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   January 13, 2025, 08:19
Default Reproducing numerical simulations
  #1
New Member
 
Join Date: Jan 2025
Posts: 3
Rep Power: 2
vix3 is on a distinguished road
Hi,
I would like to rerun a numerical simulation with an irregular sea. Is there a way to generate the same sea state more than once? For instance by using the output waves from a simulation as input to another simulation.
vix3 is offline   Reply With Quote

Old   January 13, 2025, 10:21
Default
  #2
Member
 
Alexander Hanke
Join Date: Dec 2023
Location: Trondheim
Posts: 52
Rep Power: 4
harenaobsidet is on a distinguished road
Hi.
That should be possible using for example the hydrodynamic coupling, using the state file system and initializing the later simulations with your first one or using sea state data (B85, B92=50).
Using sea state data is probably the saves as it will retain all relevant information. Coupling and state files might not retain all relevant information.
__________________
Alexander Hanke
Team REEF3D
www.reef3d.com
harenaobsidet is offline   Reply With Quote

Old   January 14, 2025, 02:57
Default
  #3
New Member
 
Join Date: Jan 2025
Posts: 3
Rep Power: 2
vix3 is on a distinguished road
Thank you for answering.


I guess when using the same module twice hydrodynamic coupling is not an option. By the B 85 parameter, do you mean to use the spectrum generated in the Log-Wave folder as input to a later simulation?


And what do you mean when you refer to the B 92 50 parameter, are you referring to the wave reconstruction method from this article:


Aggarwal A., Pakozdi C., Bihs H., Berthelsen P.A., Myrhaug D., Alagan Chella M. (2018)
Free Surface Reconstruction For Phase Accurate Irregular Wave
Generation, Journal of Marine Science and Engineering, Vol. 6, Issue 3, Nr. 105



Again, thank you for helping me

Last edited by vix3; January 14, 2025 at 04:09.
vix3 is offline   Reply With Quote

Old   January 14, 2025, 05:26
Default
  #4
Member
 
Alexander Hanke
Join Date: Dec 2023
Location: Trondheim
Posts: 52
Rep Power: 4
harenaobsidet is on a distinguished road
Quote:
Originally Posted by vix3 View Post
I guess when using the same module twice hydrodynamic coupling is not an option.
My colleague said that you could generate an irregular sea state using FNPF, let it run for the required time to arrive at a stable irregular sea state, generate a spectrum time series from this and use that as wave input for CFD.

He also found a seed value B139 for the irregular waves.

Quote:
Originally Posted by vix3 View Post
By the B 85 parameter, do you mean to use the spectrum generated in the Log-Wave folder as input to a later simulation?

And what do you mean when you refer to the B 92 50 parameter, are you referring to the wave reconstruction method from this article:

Aggarwal A., Pakozdi C., Bihs H., Berthelsen P.A., Myrhaug D., Alagan Chella M. (2018)
Free Surface Reconstruction For Phase Accurate Irregular Wave
Generation, Journal of Marine Science and Engineering, Vol. 6, Issue 3, Nr. 105
Could be, I don't know though. I'll try kicking this question to someone who has more knowledge of the wave module.
vix3 likes this.
__________________
Alexander Hanke
Team REEF3D
www.reef3d.com
harenaobsidet is offline   Reply With Quote

Old   January 21, 2025, 10:55
Default
  #5
Super Moderator
 
Widar W Wang
Join Date: Mar 2016
Location: Norway
Posts: 19
Rep Power: 11
Chalwwz is on a distinguished road
Hi,

The wave reconstruction paper you mentioned is correct.

Generally, there are two ways to reproduce the exact time series for irregular waves: 1) using a wavemaker signal (if available from an experiment) or 2) wave reconstruction (giving amplitude, frequency and phase for each component in an irregular wave train)

If one does not have any of these, one can take the irregular wave time series, make an FFT, extract the wave components information, and then use that for wave reconstruction.

Hope this helps.
vix3 likes this.
Chalwwz is offline   Reply With Quote

Old   January 22, 2025, 03:30
Default
  #6
New Member
 
Join Date: Jan 2025
Posts: 3
Rep Power: 2
vix3 is on a distinguished road
Great, thank you!


I have been testing this method by generating waves using FNPF and using the wave component file from that run as input for another run in the CFD module. It looks like the two runs are producing the same waves
vix3 is offline   Reply With Quote

Reply

Tags
cfd, fnpf, irregular waves, reconstruction

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Time-step size for coupled implicit simulations pi120 STAR-CCM+ 3 March 16, 2022 22:08
Water-Air simulations Miguel Hernandez OpenFOAM Running, Solving & CFD 26 September 18, 2021 06:38
Ways to get rid of negative pressure in numerical simulations arungovindneelan Main CFD Forum 7 July 28, 2017 05:05
Numerical viscosity due to the MUSCL and HLL coulpled scheme sonsiest Main CFD Forum 0 May 23, 2011 16:37
New Books and Numerical Software Eleuterio TORO Main CFD Forum 0 December 18, 1998 13:41


All times are GMT -4. The time now is 08:20.