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Stretching Cells Away from a Narrow Gap Face (Cells Per Gap < 1)

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    • sardar.svn
      Subscriber

      I am working on a fluent model where minimum cell volume in my domain is of determining importance. There is a baffle in my model (See image 1). Assuming that minimum sized cells are produced around the baffle (See image 2), I want these minimum sized cells to stretched away from the groove narrow face (See image 2) so that the minimum cell volume in the domain is increased. How can I achieve this? 

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      PN: Only if proximity size function is a solution, I know that "cells per gap" in the proximity size function accepts values less than unity with 0.01 being the minimum. However, I can't figure out how it works despite my tests on some dummy models I have. The Fluent User Guide 2023 pp. 561-2 reads:

      For proximity size functions, the number of cells per gap can be a real value, with a minimum of 0.01. This has the effect of increasing the size of face elements located farther away from edges, and stretching face elements with larger sizes along side faces, or gaps, thereby reducing the overall face count, and ultimately the cell count.

      In the exerpt from Fluent Guide above, what exactly is meant by "side faces"?

    • Rob
      Forum Moderator

      Side face is probably the narrow face in your domain. The documentation may include some images which reference the term. 

      You can't project a hex from that surface in Fluent Meshing. However, do you need to give the baffle a thickness? 

      • sardar.svn
        Subscriber

        Thanks Rob.

        Actually, the baffle does have a thickness, (it was first created as a body and then extracted from the fluid domain in SpaceClaim, if that's what you mean). The images seen in the original post is from Watertight UI before the tank and its baffle are volume meshed.

        But, why do you ask?

    • Rob
      Forum Moderator

      Simulation is a part putting stuff into geometry, mesh and solver and part judgement on what needs to go in. 

      So, if you include the baffle as a volume. Currently with one cell across the thin edge/face do you think you're resolving the flow? What aspect ratio will you get (hex) and skew (tet) if you aim for the mesh above? How many volume cells would you need to put 3 cells across the face with an acceptable quality? 

      Or, if we assume the baffle is "thin" ie has no physical thickness what would that do to the flow that's different to including it as a solid/volume? 

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