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-   -   [ICEM] Meshing difficulties (Hexa meshing, O-Grid, etc.). Even possible to be resolved? (http://www.cfd-online.com/Forums/ansys-meshing/87415-meshing-difficulties-hexa-meshing-o-grid-etc-even-possible-resolved.html)

JasonLam April 19, 2011 20:08

Meshing difficulties (Hexa meshing, O-Grid, etc.). Even possible to be resolved?
 
5 Attachment(s)
Analysis
Air flows into a rectangular duct in a laminar regime. Synthetic jets at the top of the channel induce mixing to improve heat transfer. I am using ANSYS ICEM 13.0 for hexa meshing then using CFX to obtain a solution.

Geometry
Part 1 - Main Channel, consists of the channel itself and the synthetic jet assembly. The synthetic jets consist of two large cavities and four smaller orifices.
Part 2 - An extension of the "inlet".
Part 3 - An extension of the "outlet"
Extensions are required to allow adiabatic walls and an isothermal bottom surface in Part 1.


Few of the things I have tried
* O-Grid on the 2 large cavities first. Splitting blocks to account for the 4 orifices ruins the two O-Grids. Counterproductive.
* After associating edge to curve, associate vertexes to the circular cavities and orifices. Split edges using Spline to match edges of blocks to curves of geometry. Actually creates more negative elements.
* Splitting blocks to account for the 2 cavities and 4 orifices. O-Grid does not work because blocks are no longer "one piece".


Problem
Determinant 3x3x3 checks show negative elements. (-0.551 to 1 on histogram at best)
They cannot be fixed using current methods. A proper solution does not exist until all problems can be resolved.

Can these negative elements be resolved?
I tried using O-Grids but if it actually works, could you prove otherwise?
This problem has been going on for at least 5 weeks.


The file limit here is about 97KB. The files I have been using (339KB) has been uploaded here:
http://www.2shared.com/file/mQ2ReA4G/Project7.html


Attachments

Picture 1 - Side view
Picture 2 - Bad Elements
Picture 3 - Front/Back view
Picture 4 - Isometric view
Attachment - Geometry in IGES format, exported from ANSYS Design Modeller.


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