I am currently taking a Finite Element Methods course, and wanted to set up a simple problem in Flow Simulation to compare results with values from a simple educational FEM solver and from hand calculations. I set up a simple 2D problem using symmetry - flow between parallel plates around a rectangular obstruction. By hand or when using the educational software, I come up with solutions to the system of linear equations for the various U values (potential for flow in this problem). I don't see a way to get the nodal values that Flow Simulation must calculate when solving - is there a way I can find these? The X and Y velocity components that Flow Simulation reports are close in value to my calculated values, but not exact.

Another question I have related to this: The mesh geometry (see attached jpeg below) for the problem I worked by hand had triangular elements. Is there a way to force Flow Simulation to use a mesh based on a user-input list of coordinates for nodes so that I might get something closer to an exact match for the solution? i.e. can I have Flow solve the problem using my own custom mesh?

Here is the six-element model. The length of the top is 200cm, the left side is 100cm, and the rectangular obstruction is 10cm high x 20cm long (these are for the quarter section as shown). Flow enters from the left hand side at 50cm/s. I also did eight, sixteen, and thirty-two element versions of this to see how increasing the number of elements effects the final solution.

I don't see a way to get the nodal values that Flow Simulation must calculate when solving - is there a way I can find these? The X and Y velocity components that Flow Simulation reports are close in value to my calculated values, but not exact.

Flow Sim is a finite volume code not a finite element code. Values are reported at the centers of the cells to thebest of my knowlegde. Also all plots are typically ellipticaly interpolated by default. I would suggest putting a sketch line through where you want the values and make a 2D plot and the values will be reported in the spreadsheet plot. Compare the profiles not individual locations would be my suggestion.

Another question I have related to this: The mesh geometry (see attached jpeg below) for the problem I worked by hand had triangular elements. Is there a way to force Flow Simulation to use a mesh based on a user-input list of coordinates for nodes so that I might get something closer to an exact match for the solution? i.e. can I have Flow solve the problem using my own custom mesh?

Flow sim uses a structured orthoganal mesh with faceting at solid fluid interface. It doesn't work like your typical continuum mechanics code that typically develop a surface mesh first and then meshes the volume. Flow sim does it the other way round - it meshes the volume then defines the solid fluid interface on a cell by cell basis. So no you can't use any other shape cell other than a brick or a faceted brick.