open TELEMAC-MASCARET The mathematically superior suite of solvers

Hello,

I'm currently trying to simulate tidal hydrodynamics in a marsh along the Western Scheldt with Telemac2D. I'm using an estuary-scale model (~200 m mesh) which is locally refined to a 8-20 m mesh in the study area.This resolution is probably quite rough to adequately simulate tidal marsh hydrodynamics, but I didnt want to refine any further with respect to computation times.

So, I'm dealing with a complex area that inundates and falls dry every tidal cycle and in which the flow directions might change quite abruptly compared to the mesh size, due to channel / creek meandering. My aim is to simulate the filling of the area and possible flood attenuation through the marsh as accurate as possible. I want to calibrate the model by varying bottom friction coefficients for the marsh channels and paltform, but I have the feeling that other parameters might be important to.

- Does anyone have experience with 2D modeling of such areas and what settings to use. For instance, Im now a bit confused about what solver is the best for this situation (1 or 7?).

- Given the changing flow directions in the channels and creeks I guess velocity diffusion / velocity diffusivity is important, but I'm not sure about the range of values I should test for this parameter (10^-4 up to 2?).

- And maybe there are other paramaters or model settings that I forgot about?


Jeroen



btw, I attached my current steering file..

Hello,

With the wave equation (treatment of the linear system = 2) the matrix is symmetric and you can use the conjugate gradient, so solver = 1.

You can add in your steering file :

TIDAL FLATS = YES
OPTION FOR THE TREATMENT OF TIDAL FLATS : 1

and, optionnally if you do not want to see slightly negative depths in the results :

OPTION FOR THE TREATMENT OF NEGATIVE DEPTHS : 2

Given your mesh size, it is wise not to rely on complex turbulence models, try a constant velocity diffusivity between 0.1 and 1 m2/s.

With best regards,

Jean-Michel Hervouet

Thank you for the quick reply Jean-Michel.

I will try different diffusivity coefficients to see what their effect is on the tidal propagation through the marsh.

Jeroen