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Hi,
I want to simulate a dambreak flood in a basin. The whole area is dry initially, and the flood discharge time series is known. I set the boundary condtion style as 455 , and create the LIQUID BOUNDARIES FILE. However the simulaiton failed and the problem is :
GIVE A VELOCITY PROFILE
IN THE BOUNDARY CONDITIONS FILE
OR CHECK THE WATER DEPTHS.
OTHER POSSIBLE CAUSE:
SUPERCRITICAL ENTRY WITH FREE DEPTH
IN THIS CASE GIVE A POSITIVE DEPTH
IN THE INITIAL CONDITIONS
OR PRESCRIBE THE DEPTH AT THE ENTRANCE.

How to solve such condition? Thank you!

Hi
The answer is written in the error message, as the condition is supercritical at the entry, you should also prescribed the depth and change the boundary condition as 555
Regards

Emmm,the boundary topography is different from point to point. Shall I write the depth for each point? Or write an average depth for all points?
Another question is that the downstream boundary condition is unknown, neither depth nor discharge. So the boundary condition is 444, right ?

Hi
You could prescribed the free surface elevation on the boundary insteah of the depth at each point.
For the downstream, 444 is ok

Regards

Hi, another more questions,please. I set the boundary condition as guidance, but the calculation result seems wrong. The bounadry entrance flux is NOT EQUAL to the discharge time series, as shown in attatchment. I tried several times but failed. Could you help me to test check the case or tell me where the problem ?
The case files are shown in attachment: syg.cas, syg_geo3.slf, syg_liq.liq and syg_bc3-bi.cli