Volume orientation
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Hi guys,
I know that this item has been discussed deeply in several previous posts but I haven't find there any suggestion which fits with my own problem so I hope not to annoying you and to find someone who can help me. Please find the attached .png file named "geometry" which shows what I need to mesh. This geometry will be used both for a CFX and a Fluent simulation where a hot gas (let's say O2) will enter the channels and flow along the pipe. I attached also two pictures which depict my blocking strategy. Has anybody got a better solution? I performed no smoothing. I just moved some vertices to obtain a mesh size as uniform as possible. I checked the mesh volume and found no negative volumes as you can see from the figure "volume_check" but had some problems with volume orientation which ICEM could not fix (see "volume_orient.png"). The quality for the elements highlighted in figure "volume_check" is poor but not negative. I tried to run my simulation with this mesh but CFX gave me the following error: +--------------------------------------------------------------------+ | ERROR #002100011 has occurred in subroutine cVolSec. | | Message: | | A negative SECTOR volume has been detected. Execution will proceed | | but this is a possible cause of robustness problems. | | The location of the first negative volume is reported below. | | Volume : -0.4257E-14 | | Location : ( -0.51447E-02, 0.28233E-01, -0.12739E-01) | | This warning may be made fatal by setting the expert parameter | | 'negative volume option = 1'. | +--------------------------------------------------------------------+ +--------------------------------------------------------------------+ | ERROR #002100012 has occurred in subroutine cVolSec. | | Message: | | A negative ELEMENT volume has been detected. This is a fatal | | error and execution will be terminated. The location of the first | | negative volume is reported below. | | Volume : -0.4237E-12 | | Location : ( -0.43662E-02, 0.27965E-01, -0.13327E-01) | +--------------------------------------------------------------------+ Does anyone have any suggestion about how to fix the problem? Thanks in advance for any help. |
you've to block this geometry with quarter o-grid (y-grid) to receive reasonable results (angles etc.)
choose the 5 blocks of the pipe, transform to quarter o-grid and then extend splits. Quote:
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Hi Christoph,
thanks a lot for your suggestion! Managing to transform my blocks to quarter o-grids I discovered that I didn't merge some vertices on the axis and that was the cause in volume problems. However I fixed it and applied the Y-grid as you seggested and now the mesh can be correctly imported into CFX and simulated. :) |
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