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TOPIC: Salinity Intrusion

Salinity Intrusion 6 years 11 months ago #28425

  • aez_lynnazs
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Hi everyone,

I am running a simplest model of salinity intrusion in simple straight channel. However, i think that the salinity value seems to be wrong. Here with attach my work and results files. Can someone check my file?

i'm really appreciate all helps and opinions for this matter.


regards
aezlyn


File Attachment:

File Name: trial.geo
File Size: 252 KB


File Attachment:

File Name: trial.cli
File Size: 43 KB


File Attachment:

File Name: cas2Dnew_2017-12-19.txt
File Size: 3 KB


Salinityresult.jpg
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Salinity Intrusion 6 years 11 months ago #28435

  • shenh
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We need a bit more information to answer your question.
- what are you trying to accomplish?
- can you also post your fortran file valro.f?
- what boundary conditions (flow, level, salinity) are you applying?
- what made you think the results are of concern?

Hailiang
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Salinity Intrusion 6 years 11 months ago #28438

  • aez_lynnazs
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Hello Hailiang,

Thanks for your respond. i'll try to give answers for the questions.

- I'd like to model salinity tracer in T2D simulation to see how dilution of salt water occur in the fresh water

-I’m just using the subroutine valro.f from source without changes anything. Is it need or not?

-In boundary condition file, I’ve set the prescribed Q with prescribed tracer in upstream channel for salinity, while prescribed Q with free tracer in the downstream channel for fresh water. The flow, level and salinity values i just put a random number

-my concern is why the salinity value in upstream lower than other section. It should be higher in the upstream due to starting point of inflow for salt water.

am i wrong somewhere?

Thanks in advance.

aezlyn

File Attachment:

File Name: valro.f
File Size: 2 KB
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Salinity Intrusion 6 years 11 months ago #28445

  • shenh
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If you did not edit anything inside valro.f, you do not need to use this file and can comment the line for Fortran file. The Fortran file is used when you edit anything for whatever purpose that is not directly supported by the base code.

Your model is setup with an initial concentration of 5 kg/m3, which is not density of water. Google the density for water under various conditions. You did not specify tracer boundary values. For upstream boundary, the concentration will be default to zero. For downstream boundary, it is free boundary which will override whatever concentration you specify i believe. However, you did not specify it anyway. If you would like to prescribe tracer concentrations at upstream and downstream boundary use keyword
PRESCRIBED TRACERS VALUES :0;0 /example value only

Your inflow rate is higher than outflow. This caused the volume in your domain constantly increasing, which can be observed from the sortie file. I do not see this setup wrong but typically I would set downstream as level boundary.

Therefore what is shown on the screenshot makes sense. Given longer simulation duration, the domain will have concentration zero everywhere.

Also, if you have field testing data, you can calibrate your model by adjusting tracer related coefficient - you can refer to the manual for details.
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Salinity Intrusion 6 years 11 months ago #28446

  • aez_lynnazs
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Thanks a lot.

correct me if i'm wrong again, am really sorry because i'm still a beginner.. :cheer:

1) what i need to do is put "PRESCRIBED TRACERS VALUES: _;_" to specify tracer boundary values, right? may i know any range of the tracer value..just to run that model.

2) as stated "typically I would set downstream as level boundary".. It means that i need to set open boundary with prescribe H..right?

i've not any field testing data yet, just to learn how to simulate the salinity intrusion in simple model.

aezlyn
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Salinity Intrusion 6 years 11 months ago #28455

  • riadh
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Hello


while you are a beginner, the best way is to stat with a validation case. You can adapt the case tracer_decrease (in examples/telemac2d).

kind regards

Riadh
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Salinity Intrusion 6 years 11 months ago #28456

  • aez_lynnazs
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Hello riadh,

Thanks. Yes, I will try it later.


With kind regards

aezlyn
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