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Hi, all. I am using the version of v8p1r1. The user manual of Gaia in section 3.5 says that the inflow boundary conditions of time-varying mass concentration values should provided in an external ascii file through the keyword LIQUID BOUNDARIES FILE.
It seems that the keyword LIQUID BOUNDARIES FILE can only be add in the main steering file rather than the gaia steering file. Moreover, if a time-varying suspend sediment concentration is used, what is the format of the sediment concentration of LIQUID BOUNDARIES FILE? I tried the file format like this bellow but I am not sure whether it is the right format. Specifically, the keyword of Q refers to discharge but how about the keyword(QG) and the unit(kg/m3) of suspended sediment concentration?

*********************************************
T Q(2) Q(3) QG(2) QG(3)
s m3/s m3/s kg/m3 kg/m3
0 64.82 9.97 4.3 9.3
17280 54.64 9.77 4.3 9.0
*********************************************
Thanks for your help!

Hi,

Hope you have solved this. If not, Why don't you impose the time-varying sediment on boundary by modifying bord.f, so no need to worry about the format of external file.

Best Regards,
Bin

Hi!

I am not an expert in the subject but I am working with suspended sediment transport and these are my recommendations:

1. I am using just 1 liquid boundary file to indicate both how my liquid discharge and my input concentration vary in time.

2. In the telemac steering file I first couple it with gaia, and then indicates the name of the liquid boundary file, using the following lines

/

---

/ COUPLING
/

---

COUPLING WITH = 'GAIA'
GAIA STEERING FILE = 'run_liquid_gaia.cas'

/

---

/ INPUT-OUTPUT, FILES
/

---

LIQUID BOUNDARIES FILE = 'bc_liquid.cli'


3. In my bc_liquid.cli I have the following format.

# Liquid boundary file test values
T Q(1) Q(2) Q(3) Q(4) Q(5) TR(1,2) TR(1,3) TR(1,4)
s m3/s m3/s m3/s m3/s m3/s g/l g/l g/l
0 16.20 1.76 0.20 -2.00 0.15 0.677 0.677 0.677
86400 20.14 2.18 0.25 -2.00 0.18 0.677 0.677 0.677
172800 11.64 1.26 0.14 -2.00 0.10 0.677 0.677 0.677
259200 10.08 1.10 0.13 -2.00 0.09 0.677 0.677 0.677
345600 8.22 0.90 0.10 -2.00 0.07 0.677 0.677 0.677

For my specific case case I have 5 liquid boundaries (4 inputs and 1 output) and then in my boundary number 1, I have three types of sediments entering (related to three sediment diameters). So TR(1,2) TR(1,3) and TR(1,4) means the input concentration (in g/l = kg/m3) in boundary 1 for sediment class 2, 3 and 4 repectively.


In the case that you are working only with one class of sediment, and that this sediment goes into your domain through boundary 1 (for example), I think the steering file would look something like this.

# Liquid boundary file test values
T Q(1) Q(2) Q(3) Q(4) Q(5) TR(1,1)
s m3/s m3/s m3/s m3/s m3/s g/l
0 16.2 1.76 0.2 -2 0.15 0.677
86400 20.14 2.18 0.25 -2 0.18 0.677
172800 11.64 1.26 0.14 -2 0.1 0.677
259200 10.08 1.1 0.13 -2 0.09 0.677
345600 8.22 0.9 0.1 -2 0.07 0.677


Again, this is just from my experience and it would be nice if an expert could double-check the recommendation.

Hope this helps.

Hi Eduardo

Thank you for your input. I am having a lot of trouble with suspended sediment concentration as well.
Are you dealing with salinity and temperature too?
What information (keywords) do you provide in your *.cas files (telemac2d and gaia), in terms of boundary conditions for tracers/sediment?
And what about your boundary condition file (not the liquid files)?

Greetings

Paulo

Hi Paulo
With respect to your questions

1.I am not dealing with salinity nor temperature, so I cannot help you there.

2.I attach the steering files with some parameter combinations that are working relative stable for me. But some quick notes about it

2a.In the telemac steering file I use the following keywords related to boundary condition and suspended sediments
/

---

/ COUPLING
/

---

COUPLING WITH = 'GAIA'
GAIA STEERING FILE = 'run_liquid_gaia.cas'

---

/ INPUT-OUTPUT, FILES
/

---

BOUNDARY CONDITIONS FILE = 'bc_steady_tel.cli'
LIQUID BOUNDARIES FILE = 'bc_liquid.cli'

/

---

/ BOUNDARY CONDITIONS, Initial Conditions
/

---

VELOCITY PROFILES = 1;1;1;1;1
TREATMENT OF FLUXES AT THE BOUNDARIES=2;2;2;2;2


2b.In the gaia steering file I use the following keywords. Just notice that in my case I have several suspended sediment classes, so the respective diameters, settling velocities, etc.. must be indicated for each one.
BOUNDARY CONDITIONS FILE = 'bc_steady_tel.cli'
/

---

/ TRANSPORT
/

---

SUSPENSION FOR ALL SANDS = YES
/

---

/ SURFACE BED PARAMETERS
/

---

ACTIVE LAYER THICKNESS = 0.005
LAYERS INITIAL THICKNESS = 0.1

/

---

/ SEDIMENT CHARACTERISTICS
/

---

CLASSES TYPE OF SEDIMENT = NCO;CO;CO;CO
CLASSES SEDIMENT DIAMETERS = 0.001;0.000027;0.00001;0.0000026
CLASSES SEDIMENT DENSITY = 2650;2650;2650;2650
CLASSES SETTLING VELOCITIES = -9;0.00068;0.0001;0.000006
CLASSES INITIAL FRACTION = 1.0;0.0;0.0;0.0
CLASSES CRITICAL SHEAR STRESS FOR MUD DEPOSITION = 0.06; 0.06; 0.06; 0.06
LAYERS PARTHENIADES CONSTANT = 1.E-02
LAYERS CRITICAL EROSION SHEAR STRESS OF THE MUD = 0.15;0.15
LAYERS MUD CONCENTRATION = 400;400

2c.In the steady boundary condition file, it depends on the type of condition you want to impose, but in general you have to change the respective flags (see gaia and telemac manual). For example, in the file that I attached, if you open it with Notepad ++, between lines 151-168 I have a boundary with given discharge and given input concentration, between 331-340 I have a boundary with given discharge and no input concentration and finally between 628 and 662 I have a boundary with given discharge (outflow from a reservoir) and a free sediment outflow. In all this cases, the difference is in column 8. The easiest way to generate this file is using BlueKenue, there are good tutorials in youtube.

3.I had a problem of sedimentation right in the boundary condition. To reduce this problem in the telemac file I used velocity profiles of 1 and treatment of fluxes at boundaries of 2. Also, when you have tidal flats + sediments, there are several instabilities problems (some which I managed to reduce but not to solve completely).

Hope this helps!

Kind regards,
Eduardo