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Hello everyone,

I have a question about liquid boundary file.

My model is about a small river. The flow can enter from the left and exit from the right, and there are some obstacles in river. So I define a liquid boundary file including SL(1) and Q(2). SL(1) is defined to 0 because water can free outflow. The question is: when the Q(2) is defined to 0, the model can run to get a result（of course velocity and depth is 0 ）.When the Q(2) is defined to values that greater than zero, the model fail to run.

I refered to this example: C:\opentelemac-mascaret\v7p2\examples\telemac2d\pildepon. But I can't solve the question

Anyone can help me?

Best regards

Hi,

You have a initial condition problem, with super critical flow at the entree boundary (as stated in your error message). Depth = 0 is not a good starting point. Try to put some water in the model using initial elevation keyword.

Hope it helps,
Patrick

Hi EnGlobe,

Thanks for you reply.

My model is similar as the example: C:\opentelemac-mascaret\v7p2\examples\telemac2d\pildepon. In this example, there is INITIAL CONDITIONS = "COTE NULLE". So I think the initial depth is not the critical reason.

I build my model and steering file is same as the pildepon example. But I don't know why my model can't run.

Best regards

Hi
Your thinking wrong!

Your model is not similar due to the fact you have positive value for bottom!
In pildepon example, using KEYWORD INITIAL CONDITIONS = ZERO ELEVATION leads to have non zero values for water depth.
In your case you don't have this.

The reason your model doesn't run is clearly written in the error message!
The advice given by Patrick is the right one!
So, please stop posting and try to follow the given advice instead.
You will save time for you and also for people who helps on the forum

Regards

Thanks a lot. It works now.

But I got a strange result.
I used STAGE-DISCHARGE CURVE BOUNDARY to set downstream boundary condition. But the result looks like wavy in downstream. I defined the STAGE-DISCHARGE CURVES FILE several times and I have no idea of how to do it.
And I want to know that TELEMAC_2D how to know this boundary is outflow.

Best regards

Hi,

I'm not sure what you mean with the results look wavy. The figure attached is water depth, so this is the thickness of water on top of your river bottom. I would look at free water surface rather, this should be a smooth(er) surface if sub-critical flow.

Having a stage discharge curve means you are doing non steady simulations, I would suggest you start with steady state first, fixed downstream water level with slowly increasing discharge towards the steady state.

Hope this helps,
Patrick

Hi,

Thank you Patrick for your advice. The results is smooth. My model works better than before when I start with steady state.

But why are there negative values in water depth? Can I ignore it?