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Update after a long day chasing bugs ...
Our attempt to add 25 new cells to a structure with thousands of existing ones has revealed dozens of ways to break the existing structure.
The process of resolving the error messages is challenging, because (it appears) a single point in the wrong place can cause a cascade of errors that adds up to many thousands.
My guess is that ChatGPT4o and I are close to finding that last pesky point, but OpenFOAM isn't much help. It tells us we have a point out of place, but it doesn't say where. Diagnosis is (apparently) 90% guess work and 10% ferreting hints out of the available data.
I sure am glad I didn't try to do anything more ambitious than adding a single ring of 25 cells to the end of the intake.
Update later:
In reviewing our steps, I went back to the beginning, and discovered that in the very first step, we somehow lost track of the count of points to be added. We added 51 instead of 52, so of course everything after that was off by that one point.
I've recreated the points and stored them in the points file.
(th)
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If there is someone in the readership who enjoys working a numerical puzzle, here is a data file that ought to be a challenge:
https://www.dropbox.com/scl/fi/lgu7thih … 9potv&dl=0
This is the output of a Python program written by ChatGPT4o to find faces in a file for the Merlin Engine model.
The faces of interest are those associated with the points that comprise the leftmost set of points in the model.
The purpose of the exercise is to replicate the 25 cells that comprise the left edge of the structure (left = -X direction).
ChatGPT4o found 177 faces with at least one of the 52 points connected.
Of those a number are duplicates because more than one point will be associated with many of the faces.
I'm looking for a number like 101 faces that are unique, and are not part of the prior set of cells.
Each cell has six sides (top, bottom, East, West, North and South).
Update: Overnight, I figured out that the faces definitions must include both inside and outside.
25 cells have a total of 150 faces if they are standing alone. In combination, some faces are shared.
In addition, if the faces are defined as both "inside" and "outside" then we get counts that look closer to the 177 we found:
top: 25 cells so 50 faces
running total: 50 of 177
+X side: 25 cells so 50 faces
running total: 100 of 177
-X side: 25 cells so 50 faces
running total: 150 of 177
+ and - Y (with shared walls) 26 (no mirror because shared?)
running total: 176 of 177
By this accounting, I am short one face.
Perhaps one side facing out in Y is mirrored? But if one, why not both?
At any rate, the mystery of the 177 count seems almost resolved, if we assume OpenFOAM needs both inside and outside of each face.
Also, in thinking about this puzzle, I realized that the faces we found must have either four points (the top layer) or two points (all others) in common with the outside points. The list we have can be analyzed for the number of points shared with the top layer.
(th)
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Work on the attempt to create a new layer of cells to be prepended to the existing Merlin Engine model is continuing.
In early study today, it has been confirmed that most of the 177 faces identified as connected to the leftmost points are mirror sets. This is consistent with the OpenFOAM structure of "inside" faces and "outside" ones. The only faces that do not have mirrors are faces that are shared between two cells. Study so far is still delivering mysteries. For example, a study to find mirrors in the 177 faces found earlier resulted in identification of six faces that do not meet the minimal criteria of a mirror.
Investigation continues.
(th)
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