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Hello All,

I am modelling a beach littoral flow scenario with T2D, TOM, and SIS coupled and I would like some clarification or help understanding the evolution and bedload outputs from Sisyphe.

The bedload output shows movement of sediment in the wave breaking zone along the beach, which is what is expected. After seeing this I expected to see the same trend in the evolution output, but instead it shows a very patchy/blotchy sediment transport with no clear sign that the sediment is moving in the direction of wave action or T2D flow. I am wondering if I have something set in correctly, or if I am misunderstanding the evolution output.

Ultimately I would like to see how the beach transforms due to a marina structure that I have inserted in the grid.

It looks like you have no wave breaking. You want to change the setting of

DEPTH-INDUCED BREAKING DISSIPATION = 0
Without wave breaking, the wave forces will be small, limiting the sediment transport and the evolution.
The evolution is matching the beload transport I think, with deposition in areas where the transport rate reduces (as function of alongshore location) and erosion where it increases (as function of alongshore location).

Hi Michiel,

Thanks for the reply.

I turned DEPTH-INDUCED BREAKING DISSIPATION to 0 as my waves were breaking in water that was far too deep for them to be breaking in, but the parameters that I am using have changed quite a lot since I set this parameter to 0 so I will try changing it.

Do you have any suggestions for alleviating the blotchiness/patchiness of the evolution results? I was expecting something smoother like in the bedload plot that I included.

Hello Again Michiel,

I have attached two figures to show the issue that I am experiencing. In both figures the left portion shows the results with DEPTH-INDUCED BREAKING DISSIPATION = 2 (Battjes and Janssen) while the right portion shows the results with DEPTH-INDUCED BREAKING DISSIPATION = 0 (no breaking-induced dissipation). Each has a wave height of 2.5 m applied to the offshore boundary.

The wave height figure shows that the wave is losing more energy than I thought it would when it is in deep water with the DIBD set to 2 (Please see my initial post for the bathymetry). The wave maintains more energy further inshore when the DIBD is set to 0. The bed shear stress figure also shows that higher shear stress is present close to shore in the breaking zone with DIBD = 0. This also translates to more sediment evolution in a shorter time.

Is this result expected or do I have something else in my model set incorrectly that would produce these results?

Any help is greatly appreciated.