Feflow 7 - Set up 2D rectangular grid of exact measurements, then make it 3D?

Hi -- I am looking for a way to make a rectangular grid 1000 metres wide (i.e. X direction being east-west), 100 metres in the north-south direction (i.e. Y direction), and 10 metres high (i.e. Z direction, so the top surface of model has an elevation of 10 metres above the bottom, and so the bottom of the model is the datum).

I was planning to start with a 2D model (i.e. 1000m by 100m in plan view), and then extrude it to make it 3D by adding the vertical dimension.

The dimensions of each element should be exactly 1 metre on each side, so each element has volume of 1 cubic metre.

Later, I will want to subdivide the elements so that each element is a half-metre on each side (and therefore the number of elements will increase by a factor of eight).  So, I will want to be able to do this easily too.

By the way, I have done all this before in Modflow, where it was very easy to set up.  (In standard USGS Modflow in Fortran, it is easy to set this up.  I note that, in both Visual Modflow and Groundwater Vistas, it was a simple and intuitively obviously operation.)

So, what are the steps for doing this in Feflow 7?  It should be really easy to do, and this problem not complicated, but the Feflow user interface is so completely different from every other modelling package out there, and so I am stumped.

Thanks,
Michael.

For the supermesh, digitize a rectangular box of 1000x100 m. You can do this by activating the polygon option, hitting F2 and typing the coordinates for each corner node. Then switch to 'Quadrilateral mode' in the Supermesh menu and use the 'Transport Mapping' mesh generation algorithm in the Meshing panel with a number of 100000 elements. This will give you the first grid. For later refinement to half-meter elements, select all elements and click 'refine' in the Mesh Geometry toolbar.

In FEFLOW which is primarily focused on flexible-mesh modelling, the generation of a rectangular grid is a rarely used 'special case' - thus the procedure might be less obvious thanin VM or GV where rectangular grids are (still) the standard.

Hi Peter -- thanks for your reply.  I was able to digitize the rectangular box, and I have selected the Quadrilateral Mode and the Transport Mapping mesh-generation algorithm.  Unfortunately, I cannot find an "Edit Proposed Elements" button (which, according to the Feflow 6 Transition Manual, should appear in the Generator toolbar).  How do I get it to appear?

Thanks,
Michael.

This depends on the version you're using. Up to 6.2 you'll find an input box in the Mesh Generator toolbar - this is for the proposed number of elements. From 7.0 on, the whole meshing process is done via the new Meshing Panel. There you click on the entry for the respective superelement (your polygon) and enter the number of elements in the settings for the polygon.