open TELEMAC-MASCARET The mathematically superior suite of solvers

Hello,

I Tried to run a 3D simulation of a rectangular domain representing a part of a Sea. I assigned the boundary conditions as the following:
1 side as a solid BC and the rest three sides were assigned as 3 open boundaries ( 2 with prescribed water elevations and 1 with prescribed discharge). My problem is that when I run the simulation, the values of discharge at the boundary do not match the assigned values. For example, If the prescribed boundary discharge is 600 m3/s, I found the discharge through the same boundary as 623m3/s during the calculation listings. I do not know why!! (Note I tried it in versions V6P3 and V6P1 under windows, with and without parallelization)

Another question, I tried to change the boundary which includes the corner points. But, in this case telemac3d read it as 2 open boundaries instead of 3.

I included the files for both models

Thanks for help

Hello,

I have changed the boundary condition file so that the open boundaries are disconnected. I found that the discharge shows as 600 m3/s.

In the original case, I think possibly the value 623 m3/s is expected as the calculation may also considers the contribution of flow at the adjacent nodes on the edges of the discharge boundaries which happens to be the next open boundaries where elevation is imposed.

Possibly someone on the forum may have some more comprehensive explanation on this issue.

With Best Regards,
Gourish

Hello,

Thank you for your help and for your time

I tried the same as you have done before. but by this you create like a contraction which will affect the flow pattern. I am interested in simulating gravity driven flow and this will change the whole result. I still do not understand why it take the effect of the flow through the adjacent imposed elevation points, especially that I specified the discharge as entering the domain (not leaving). and it is interesting that by only changing the allocation of the corner point the mass balance and the number of boundaries taken in to consideration is different. does any one know how to solve this without affecting the flow pattern.

Best Regards
Mahmoud Shehata