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Femwater


mohamed jalal
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Hello Everybody,

I am applying GMS-Femwater at a medium field research site (A=450Km2). and having problems with Simulation, the Femwater run simulation and he finished but not successufly. The domain is irregular and slopes downhill. I have a flow on the North-West and Sud boundaries. There is different recharge on top, and no flow on the bottom. At the moment I am looking for a steady-state flow solution and i have a 8000m in Head but in refernce it’s about 400m . I prupose the problem of model is produced by :

1. in unsaturated area, convergance problems seem to arise near the water table due to the sharpness of the van Genuchten release curves for the soil (heterogeneous, which I don't know how to approximated, but i have a value of moisture is 66%) and i dont’t how to input-it.

and I have some Questions:

1- How to calibrate in femwater because i have heterogeneous materials for unsaturated & saturated area?

2- Femwater applies in heterogeneous or just in homogeneous materials?

3- How much area applies in femwater ?

Thanks :rolleyes:

J2al,

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Hello Everybody,

I am applying GMS-Femwater at a medium field research site (A=450Km2). and having problems with Simulation, the Femwater run simulation and he finished but not successufly. The domain is irregular and slopes downhill. I have a flow on the North-West and Sud boundaries. There is different recharge on top, and no flow on the bottom. At the moment I am looking for a steady-state flow solution and i have a 8000m in Head but in refernce it’s about 400m . I prupose the problem of model is produced by :

1. in unsaturated area, convergance problems seem to arise near the water table due to the sharpness of the van Genuchten release curves for the soil (heterogeneous, which I don't know how to approximated, but i have a value of moisture is 66%) and i dont’t how to input-it.

and I have some Questions:

1- How to calibrate in femwater because i have heterogeneous materials for unsaturated & saturated area?

2- Femwater applies in heterogeneous or just in homogeneous materials?

3- How much area applies in femwater ?

Thanks :rolleyes:

J2al,

Hi Jalal

1. To simulate heterogeneous materials, you need to create different material zones (e.g. layers), and assign different materials/properties to each.

2. It is important to check your unsaturated zone curves. What unsaturated zone curves are you using (e.g. van Genuchten) and what version of GMS do you have, as there was a bug in the van Genuchten curve generator in earlier versions.

3. What is your vertical mesh discretization?

4. Try turning the spline interpolation option off, as this can cause problems.

5. What options and iteration parameters are you using?

Feel free to email me directly at woodward at lvlham dot lincoln dot ac dot nz

Simon

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Hi Mr. Woodward

1.I have heterogeneous materials in one layer, and i don’t how create material zones in 1 layer.

2. I have GMS 6.5 and i turned on Manual Paramater input and in saturated water content i put a value of moisture (0.66).

3. I don’t how i assign vertical & horizontal discritisation are defaut

4. I turnd off the spline interpolation, but i have the same problems.

5. In run options i use Pointwise iterative matrix solver & in parameter iteration i use 100 for non-linear equation.

Thanks,

J2al,

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Hi Mr. Woodward

1.I have heterogeneous materials in one layer, and i don’t how create material zones in 1 layer.

2. I have GMS 6.5 and i turned on Manual Paramater input and in saturated water content i put a value of moisture (0.66).

3. I don’t how i assign vertical & horizontal discritisation are defaut

4. I turnd off the spline interpolation, but i have the same problems.

5. In run options i use Pointwise iterative matrix solver & in parameter iteration i use 100 for non-linear equation.

Thanks,

J2al,

1. In the 3D mesh mode, I think you can isolate one layer, then select the elements you want, and set their material. It might be easiest to set the material parameters for all the materials first (it's a bit of a pain in GMS). You'll have to fiddle around in the 3D mesh mode editor, isolate is a useful command.

2. Saturated water content is set via the unsaturated characteristic curves (water content at pressure head = 0). Be careful as the van Genuchten alpha is in 1/cm in old versions of GMS

3. By discretization I mean the size of your mesh elements and the number of mesh layers.

4. Leave it off.

5. Send me the project text files (fws,3dm,3bc,initial phd) if you like and i will have a look at it. My email is above.

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hi Mr. woodward,

i don't how to send Email directly in your account because i don't have a permittion to send it,

Can you tell me if possible your Gmail, Hotmail or Yahoo Adress email if possible etc..,

Thanks,

J2al,

The address I gave above should work. They are all "L"s not "1"s.

Give me your email address and I'll email directly.

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