|
[Sponsors] |
![]() |
![]() |
#1 |
New Member
Conor Crickmore
Join Date: Oct 2017
Location: Loughborough University, UK
Posts: 12
Rep Power: 8 ![]() |
Hello everyone,
I'm encountering a rather odd issue that no amount of tweaking seems to resolve, bare in mind I am new to CFD and STAR so I may be doing something stupid. I am getting a tiny (like in the same order of magnitude as the Near Wall Cell) cell forming between my outermost prism layer and my core mesh but only on my geometry walls (not the roof, floor and wall of my 'Wind Tunnel') Alongside this, I am also getting a strange collapse-like issue at the trailing edge of the geometry. The Prisms aren't actually collapsing, and are continuing along the geometry. Visual representations can be seen here. I'd tried changing the thickness, number of layers, and numerous other parameters and nothing seems to rid me of this issue. Again, apologies if this is a simple issue/non-issue that I am unaware of, Thanks |
|
![]() |
![]() |
![]() |
![]() |
#2 |
Senior Member
Ping
Join Date: Mar 2009
Posts: 556
Rep Power: 20 ![]() |
it is not clear what your are showing in those images and are you sure you are looking at prism cells anyway
do other sections and also use the prism layer field function to clearly show where prisms layers are in a scalar scene cross section |
|
![]() |
![]() |
![]() |
![]() |
#3 |
Senior Member
Join Date: Nov 2010
Location: USA
Posts: 1,232
Rep Power: 24 ![]() |
You are seeing an artifact of using a cutting plane. The cutting plane is not perfectly cutting through only one sheet of cells in a plane, it cuts through all of them. So you will see small wedges and weird shapes where a cell has been chopped.
If you want to see the actual cells use a cell surface. |
|
![]() |
![]() |
![]() |
![]() |
#4 |
Senior Member
Ping
Join Date: Mar 2009
Posts: 556
Rep Power: 20 ![]() |
to see the actual cells it is better to use a threshold since cell surface only show the first layer
|
|
![]() |
![]() |
![]() |
![]() |
#5 |
Senior Member
Join Date: Nov 2010
Location: USA
Posts: 1,232
Rep Power: 24 ![]() |
I don't agree with that. A cell surface can show any 'layer' of the mesh if you give it a plane section as input. Getting a slice of whole cells in a mesh with a threshold is difficult and expensive.
|
|
![]() |
![]() |
![]() |
![]() |
#6 |
Senior Member
Ping
Join Date: Mar 2009
Posts: 556
Rep Power: 20 ![]() |
you are correct me3840 i forgot cell surface is not just for boundaries
and it can be enhanced considerable by using this new derived part in a scalar scene using the prism layer cells field function which clearly shows which cells are in the prism layer and the rest as shown in the attached image but this feature only works if you mesh using the newer parts based meshing which you should be using anyway these days |
|
![]() |
![]() |
![]() |
![]() |
#7 |
New Member
Zachary MacChesney
Join Date: Jan 2017
Posts: 6
Rep Power: 9 ![]() |
Hi Conor Crickmore.. I graduated from Lboro a few years ago.. are you doing the CFD module with Henk?
![]() Regarding your issue.. Have you enabled the surface wrapper / surface remesher? Sometimes things like that happen as a result of the specific geometry and the algorithms that generate the mesh.. often you can just ignore them unless they present a serious problem to your simulation such as divergence or other nonphysical results.. |
|
![]() |
![]() |
![]() |
![]() |
#8 | |
New Member
Conor Crickmore
Join Date: Oct 2017
Location: Loughborough University, UK
Posts: 12
Rep Power: 8 ![]() |
Quote:
Speaking to Andrew, it does seem like this particular issue is just an artefact of the the plane 'cutting' the 3D cells as, as you said, it doesn't seem to be causing any serious issues. |
||
![]() |
![]() |
![]() |
Tags |
prism layer |
|
|
![]() |
||||
Thread | Thread Starter | Forum | Replies | Last Post |
CFD analaysis of Pelton turbine | amodpanthee | CFX | 31 | April 19, 2018 18:02 |
Prismatic boundary layer | KateEisenhower | enGrid | 5 | September 15, 2015 07:48 |
[snappyHexMesh] Improving prism mesh | me3840 | OpenFOAM Meshing & Mesh Conversion | 2 | April 2, 2014 04:37 |
[snappyHexMesh] Layers:problem with curvature | giulio.topazio | OpenFOAM Meshing & Mesh Conversion | 10 | August 22, 2012 09:03 |
[snappyHexMesh] Boundary layer generation problems | ivan_cozza | OpenFOAM Meshing & Mesh Conversion | 0 | October 6, 2010 13:47 |