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akashnag10 October 28, 2023 10:13

Need Help for scouring analysis in REEF3D
 
2 Attachment(s)
I am a Masters student at IIT Madras.

I am currently working on a thesis project focused on the numerical modeling and prediction of local scour around offshore monopiles.

I have been dedicating a significant amount of time to learning and utilizing the Reef 3D software. Unfortunately, I have encountered some challenges and have not been able to obtain any scouring on sea bed.

Can you please check these input files? We are not getting the scouring around monopile.

Felix_Sp October 29, 2023 03:41

Hello,

you are missing a topography or your bed. I would suggest increasing your domain in negative z-direction for some amount in your control.txt. For example: B 10 0.0 4.4 0.0 2.0 -0.2 0.7.

In the ctrl.txt you have to set S 57 to 0.0 (I guess that is your bed level?).

Also think about your S41/S42 options, as I do not know whether the defaults are what you want.

Furthermore, I would add S71 and S 72 to your ctrl.txt to minimize problems at the inlet and outlet. For example, S 71 0.5 S 72 3.9

Just for your awareness, S 12 does not work at the moment. So suspended load is still not fully functioning.

Also, if you want to use B 98 2 and B 99 2 B 96 needs to be way larger. It says one wave length in the manual, and your wave length is approximately 9 m. At the moment, you only have 0.5 meter. If you want a short flume, you can try B 98 4 and B 99 3. But I do not know whether in your case this is enough to minimize reflection at the boundaries.

Also, use only P 30 or P35. Or for your case even P 34.

Also, your wave flume is not high enough. I would set your numerical domain height to at least 1.3 m (~ wave height + water depth times 2).

Cheers

akashnag10 November 7, 2023 05:02

Need Help for scouring analysis in REEF3D
 
2 Attachment(s)
Hello Felix,

I made the necessary changes as you had mentioned. Still the topography or sediment patterns and scouring is not visible. Please check the files once.

Can you please share any reference txt files?

Felix_Sp November 7, 2023 11:42

Hello

don't use S 10 2 it is not well tested. Here it decreases your shear rate. Use S 10 1. In my simulation your setup generates a shear rate that is still lower than the critical shear rate. Therefore, there is no Erosion. Maybe try a different S 16 option. Whether this is physical for your case I do not know. Otherwise, you have to find out why the critical shear stress is lower than your generated shear stress (e.g. sediment parameters + wave parameters + numerical setup).

Also clean up your control.txt of the last line, it might be problematic otherwise if you change your input in the future. You are still Printing with P 34 and P 35.

Cheers


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