open TELEMAC-MASCARET The mathematically superior suite of solvers

Hello community!

I simulate a water flow through a valley in telemac2d(v8p3r0). I set two open boundaries,one for the inflow boundary(4 5 5) and the other for the outflow boundary(5 4 4). And the bathymetry is 770.
When I set the flow rate the process is slowly increasing and then decreasing(overflowing), the entire calculation is correct.
However, when I set the initial moment the traffic is maximum, and then slowly decreases, the calculation does not converge.At 1second, the VOLUME IN THE DOMAIN is 0.2789388E+14 M3!!!SO MUCH!! And there might be something wrong.I wonder if some of the keywords don't apply.

I attach the files at the last.

Kind regards,
ryuuame

Greetings ryuuame,

It seems that your simulation is having issues in the first time-steps around your second boundary condition. You prescribed an elevation of 770m in your first open boundary (the one with no discharge) and a variable discharge from the lqd file on the second boundary condition.

Did you check that this elevation is consistent with your model ? (river bed under that value), as a reminder, the PRESCRIBED ELEVATIONS are the values of the free surface of your flow.

It also seems that you have a supercritical flow at your inlet (boundary 2). Maybe you should initialize your model by forcing a bit of water next to the inlet and also check that you have smooth bathymetry with a straight (not curved) boundary. If possible you could also try to change the velocity profile (to 4;5 in your case).

In last resorts, you can also try to see if it works better with a fixed flowrate and prescribed elevation, in that case the issue might lie in your liquid boundary file.

Thanks for your reply, zied.amama

What does it mean of "forcing a bit of water next to the inlet"? Shall I change the inlet boundary from 4 5 5 to 5 5 5, and give the HBOR value?

Besides, could you tell me how to check the smooth bathymetry with a straight (not curved) boundary? As you said to try the velocity profile, actually I don't have the velocity datas. So I have to use the dischrage profile.

Meanwhile, I tried to simulate the calculation with a fixed flowrate and prescribed elevation. But it does not work as well.

Regards,
ryuuame