open TELEMAC-MASCARET The mathematically superior suite of solvers

Hello everyone,

I am a PhD student and a new user of Telemac. I want to model tides and tidal currents on historical bathymetry maps. But I have a probleme with the tide propagation.

My study area is the Northern France, you can find attached my grid (1)(between the Cap Grid Nez and Graveline). My boundary conditions are calculated using tidal harmonic constants and I propagate tides on the bathymetry.

As you can see in the file attached (2), I plot my results : in blue, the sea-surface calculated by Telemac near Calais and in orange, the sea-surface from the model, but close to the boundary. The sea surface in Calais is very strange and I found same results in any point in the grid.

At the boundary, the signal is ok. I think it's during the tide propagation but I don't know how I can fix it.

Have you ever see this before and/or have you an idea of what it is ?

Thanks for your help,

Alexa

In my first post, the second picture wasn't in the good format, here all attachments.

Hi
What about the initial condition?
Did you impose the same boundary condition on all boundary nodes?

In my opinion, I would try to use tpxo initialisation and boundary condition to see if the result is the same or not...

Hope this helps

Hi,

Thanks for your answer.
For the initial condition I consider an initial elevation (cote initiale) of 0.15m imposed in all the nodes. I read in previous studies that it helps to stabilize the model.
For each boundary nodes and every step, I calculate the water level with harmonic constant (I use cst-France), so water level is not the same in all boundary nodes.

I try with an other grid, and I don't have these sea-surface fluctuations. Maybe it's in the geometry grid ? Or the bathymetry ?

Constant initial elevation and different water level on boundary nodes could create some initial shock that could be hard to damp sometimes...
If you found a solution which works with a different grid, there is no needs to investigate the previous model

Regards