3-d layered model - slope in more than 1 direction

[jeff_k]

I'm trying to build a 3d layered domain model to simulate recharge basins. Everything is fine: building the model, generating the mesh, defining boundary and initial conditions, running the model. The model has some irregular openings/interior surfaces to define mesh refinements.

Now, I'd like to skew the model geometry to represent a sloping water table. I can use the Slope... command to do so; with the slope defined by the x- or y- coordinate, and a non-zero value for the z-coordinate slope angle, I get the result I want.

The problem is, the direction of slope is at a 45 degree angle to the model grid. I can achieve this by running Slope... twice: once with slope defined by the x-coordinate, then with slope defined by the y-coordinate. But, after doing this, the extrusion that creates the 3-d domain only recognizes the interior openings, not the interior surfaces. That is, I get holes in my 3-d domain. The interior surfaces that used to be defines as "Base Surface" are now defined as "Planar". FWIW, this is only a problem with irregularly shaped interior openings - rectangular ones are retained as part of the base surface.

Again, it works fine when only applying Slope once on one axis. I also tried rotating the geometry 45 degrees, applying "Slope...", and rotating back. After the second rotation the "Base Surfaces" are converted to "Planar" and I have the same problem.

If that makes sense, are there any suggestions? I'd prefer not to work with a rotated grid as I have several monitoring locations where I need to make model predictions.

Thanks

[Mirek]

I'm not sure what the problem is. Can you attach your project (before and after rotation) as a ZIP archive? Alternatively, you can send it to support@pc-progress.com.

[jeff_k]

Thank you for taking a look.

Project "...slope1" is after applying slope once - everything is fine. The screenshot in the .zip shows the Slope dialog settings.

Project "...slope2" is after applying slope twice - there are holes in the volume and I can't generate a mesh.

The 3 curves (ovals) in the center of the project are used both for defining grid refinements and setting boundary conditions. To me, it looks like Hydrus recognizes that they are contained in the surrounding surface (#22) for the purpose of creating openings, but they are not recognized as part of the base surface.

If I remove the openings from the slope2 project, I can define the boundary conditions on the mesh. That's an OK workaround, but it would be easier to define them on the geometry.

Thanks for any help. I'm also happy to take feedback if anything else in the model looks unusual. Other than that, It's working well for my purpose.

[Mirek]

Your domaim is relatively large (2 x 2 km) and the automatic detection of Base Surfaces stops working properly after its greater inclination. The solution is to turn off automatic detection and define Base Surfaces manually - see the first image. Then the FE=mesh can be generated correctly - see the second image.

Base_Surface.jpg (389.64 KiB) Viewed 29486 times

Mesh.jpg (829.46 KiB) Viewed 29486 times

[jeff_k]

Great! That was just what I was missing. Thank you very much.