open TELEMAC-MASCARET The mathematically superior suite of solvers

Hello TELEMAC community! Happy holidays...

For the last 5 months, I am struggling to make a model in the Larantuka Strait in Indonesia. I am grateful to say that I almost made it!

However, there is this minor issue.
This is the map of the strait


at the entrance of the strait, (Point 1 and 2) the time series are nice and smooth





However, as it goes into the center of the strait (Point 3 and 4), it becomes jiggly and unstable





I wonder what causes it since I want the results to be smooth and clean. I will attach the steering file, geometry file, and boundary conditions file.

Thank you! Hope you all enjoy your holiday seasons :)

Hello Michael,

Looking at your steering file, I have a few questions:
- why have you chosen DISCRETIZATIONS IN SPACE : 12 ; 11? I.e. quasi-bubble to discretise velocities?. This type of element is more accurate than linear choice (11) but should be handled with care, you may have to decrease the time step,
- why have you chosen OPTION FOR THE TREATMENT OF TIDAL FLATS : 2? It is recommended to use choice 1, without frozen elements.

I would try the recommended default options: DISCRETIZATIONS IN SPACE : 11 ; 11 + OPTION FOR THE TREATMENT OF TIDAL FLATS : 1 and if you stil have spurious oscillations, reduce the time step and/or decrease FREE SURFACE GRADIENT COMPATIBILITY, even until 0.

What about the size of elements where the velocities are the bigger?
What about the bottom elevation where you have spurious oscillations?

Hope this helps,

Chi-Tuan

Hi Pham

SOrry took longer to respond to your suggestions. I immediately applied your suggestions:

- Changing the DISCRETIZATIONS IN SPACE back to linear (11;11)
- Changing the OPTION FOR THE TREATMENT OF TIDAL FLATS back to 1 (all elements included in the calculations)
- Reducing the time step from 4 to 2
- Reducing FREE SURFACE GRADIENT COMPATIBILITY from 0.2 to 0.1

AND IT WORKS LIKE A CHARM! The velocity looks great as well!







Thank you, Pham. Simple things, but you just saved my holiday
I hope you have a great end of the year and a new year full of hope!

Cheers,
Michael

Good news if it works now.

Cheers,

Chi-Tuan