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Hello,

I am trying to develop a simple SISYPHE model where I wish to impose a suspended sediment concentration at the upstream boundary. I was able to find an example that does just that (attached). These files were given at the TUC2013 conference.

What I am confused is this: the line in the SISYPHE steering file that says

CONCENTRATION PER CLASS AT BOUNDARIES : 0.;7.5E-5

which I understand imposes a suspended sediment volumetric concentration as 7.5E-5 at the flow boundary.

However, if I complete the simulation, and I extract the time series results at the input boundary, I get a suspended sediment concentration of 1.5E-5 (from variable CS1). How come the results file does not output the same concentration as specified the input file?

Am I getting something messed up with units? Can someone tell me how to read the input and output of suspended sediment concentration, and convert to it units like g/L?

Thanks in advance,

Pat

Dear Pat,
sorry for the delay in responding.
In the files that you post in the forum, the keyword EQUILIBRIUM INFLOW CONCENTRATION is activated, computed then by an equilibrium concentration formula.
If you activate the keyword CONCENTRATION PER CLASS AT BOUNDARIES : 0.;7.5E-5, in the output file you will get the volume concentration (flag 'CS1'). Probably what you are looking at in the output file is the QSSUSP that is the suspended load transport rate, expressed in m2/s (and that is the value that you mention in the post).
A word of attention must be put is you use the keyword MASS CONCENTRATION. In the case the ONLY THE OUTPUT is expressed in g/l and the values given in the steering file for the concentration per class at boundaries must be given in terms of volume concentration.
This will be correct for the next release of the TMS.

I hope it helps,

Pablo

Now, I know how to apply time-varying sediment concentration.
but it can be done just when I have one inflow..
When I apply two inflow boundary, it breaks.
Is there anyone who got this problem like me?
Hope your kindness.
Thanks.
Sincerely.

Hi
Maybe you could give more information about the crash. You could also describe the change you've done between the model with one inflow which works and the model with 2 inflow which breaks.
It's hard to help you without any information...
Regards

Thanks C.coulet for quick reply.
I attached my liquid boundary file for time-varying sediment concentration below. For example 1, it was well done. but when I just apply 2 inflow like example 2, it breaks. and others are same exept sisyphe liquid boundary file.

[Example 1]
below you can found a sample of the "LIQUID BOUNDARIES FILE"
# Temps (s) Conc_inflow Discharge (m3/s) WSE(m)
T Q(2) CG(2) SL(1)
0 100.0 0.1 200.0
1800 100.0 0.1 205.0
5400 200.0 0.2 205.0

[Example 2]
below you can found a sample of the "LIQUID BOUNDARIES FILE"
# Temps (s) Conc_inflow Discharge (m3/s) WSE(m)
T Q(2) Q(3) CG(2) CG(3) SL(1)
0 100.0 110.0 0.1 0.1 200.0
1800 100.0 110.0 0.1 0.1 205.0
5400 200.0 210.0 0.2 0.2 205.0

The order of it is right?
Hope your help again.
Thank you.

Hi

What is the message when the crash occur?
Are you sure that the liquid boundary numbering is the right one?
It depends the location of the liquid boundary on the boundary itself!
Maybe with 2 inflow the order change...

Regards

Dear Pablo and telemac user.
Nowdays, I wonder how I can apply time-varying sediment concentration.
In previous bulletin board message, I can find example for liquid boundary file.

============================================================
below you can found a sample of the "LIQUID BOUNDARIES FILE"

# Temps (s) Conc_inflow Discharge (m3/s) WSE(m)

T Q(1) CG(1) SL(2)

0 100.0 0.1 200.0

1800 100.0 0.1 205.0

5400 200.0 0.2 205.0
... ... ... ...
=============================================================

When I make liquid boundary file in T2D,
This variable and value can be easily wrotten by using TIME CURVE.
And the name like Q(1), SL(2) is automatically specified.
but I'm confused about CG(1) above example.
It seems like sediment concentration.
But I can't make liquid boundary file like that.
Should I write CG(2) manually myself?
Or is there any other way?

I also find that somebody use Tracer for time-varying concentration.

In a word, could you explain how I can apply time-varying sediment concentration?

Thanks for your attention
and hope your work goes well.
Sinecerely.