[IADInocencio]

Hi good day again, sorry for the incessant posts and queries. But am generating the ctrl.txt incorrectly for irregular waves? Whenever I toggle to B 92 31 it gives me a segmentation fault; the start and end of the error message is attached as images. But if I switch it back to B 92 2, it works just fine. I think I must be missing some code definition somewhere that I am not aware of.

ctrl.txt

control.txt

error1.JPG

error2.jpg

[Chalwwz]

Hi,

Thanks for sharing the problem and control files. The main issue that leads to the crashing is that you used B 91 option for the irregular wave generation, i.e. defining Hs and wave length (corresponding to Tp). However, we only supported B 93 option with Hs and Tp for irregular waves. It is recommended to use B 93 since this is the common practice to use Hs and Tp for irregular wave spectrum definitions. Option B 91 is also made available now in the new code, should be working in the next release.

Aside from the crashing issue, there are also some suggestions and tips to improve your simulations:

1. For irregular wave, you often need to define more parameters, e.g. 1) the spectrum that you want (B 85), 2) the number of wave components you need (B 86) and the starting and ending frequency of your frequency band of choice (B 87).

2. F 42 in your ctrl.txt should be 10.0 instead of 1.0. It should be the height of your numerical wave tank and be larger than F 60, the still water level. F 42 in ctrl.txt should match the last digit of your B 10 command in the control.txt file.

3. We don't use capital letters in the comment sections (e.g. you used '// ... Longuet-Higgens'), sometimes the program will interpret them as commands even though they are in the comment zone after the // sign.

4. It is recommended to use longer wave tank for irregular waves (15 peak wave lengths), it helps with more stable wave statistics.

5. For you case, it is recommended to use relaxation method for the wave absorption, i.e. B 99 1, since your water condition is quite deep and active wave absorption (B 99 3) works the best with shallower waters.

Try using B 93 and follow the suggestions to change your setups, it should work better.

Good luck!

Weizhi

[IADInocencio]

Good morning Weizhi,

Thank you for the very detailed response! Going through item by item:

1) Yes I realized this after I had posted and tried adding these but it would still not run correctly, likely because I did not address the issues related to your other suggestions
2) I had not thought to switch to defining Hs and T instead of L.
3) Thanks for confirming this potential issue, I was also getting errors in my other Channel simulations saying that the ctrl and control.txt's have different number of core definitions whenever I added comments, even though I was sure they were correct.
4) Thanks for this suggestion, I will definitely increase the length later on; I was limiting it to a small wave tank right now just to try and get a stable run going on. I am just on a 6 core laptop, so simulations take a while
5) If I intended the waves to be impinging on a slipway (around 12% slope) or a revetment with a seawall, would relaxation still be recommended?

Again thank you for your suggestions!

[Varada]

To create waves within a numerical wave tank using a spectrum, is it essential to activate B 92 along with B 85, 86, 87, and 93? If so, which wave theory would be the appropriate choice for this scenario?

[Chalwwz]

Hi, normally you can choose '1-st order irregular wave' for B 92, that is option 31. B 85, B 86, B 87 are always activated, either using user-defined values or the code will take the default values in pre-set in the program as indicated in the user manual as well. B 93 is also essential, because here you defined Hs and Tp, which in term influence the spectrum shape.
- Bests, Widar