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Hi to all,

I'm new of telemac-2D. I try to run a basic simulation of my case.

MelanProject_H case, i only give waterleve downstream boundary,
that simulation run is success. (i just try, don't care result is right or not)

but when MelanProject_HQ case, i give waterleve downstream boundary,
and discharge upstream boundary, its got a error tell me check waterlevel.

Two case also started the simulation with an intial depth of 0.01 meter.
how can i solve this problem? Can anyone give me suggestion?

Thanks in advance.

Hi

Did you tried with a higher initial depth. 1 cm is probably not sufficient to impose the discharge.
If it work cith a higher value, you could try to make a hot start with the first result to well initialize your computation

Hope this helps

Thanks for reply.

I have tried with higher initial depth,
but still fail when second or third time step.

I think reason is my mesh domain is relatively big,
so second or third time step upstream then waterlevel can impose the discharge.

In this case, how can i solve this?

Thanks.

Hello,

You should not start with a constant depth, which will trigger strange movements at the beginning, but with a constant elevation. If you cannot start with a constant elevation because your model is too long and it would give too much depth at one end, preprocessors like Fudaa or Blue Kenue can help you setting a not too unphysical initial free surface.

If you start from dry domain and want a discharge to enter the domain, it will not work (the initial depth is taken to start with, to find what should be the velocity that will give the correct discharge), and an extra problem is that flow on dry land is supercritical, so the boundary condition at your entrance would change when the flow becomes fluvial after some time.

A solution if you start from dry land can be to add a small artificial section at your entrance, with a lower bottom elevation, and fill it with water, so that in all cases the flow at the entrance will be fluvial.

I hope this helps,

Jean-Michel Hervouet (still in Vietnam...)