CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > Siemens > STAR-CCM+

Prism layers at sharp corners

Register Blogs Members List Search Today's Posts Mark Forums Read

Like Tree1Likes
  • 1 Post By Nikpap

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   October 31, 2022, 10:17
Default Prism layers at sharp corners
  #1
New Member
 
McVas
Join Date: Oct 2022
Posts: 17
Rep Power: 3
technoB is on a distinguished road
Hi,
I'm attempting to simulate turbulent flow over a rectangular shape and i'm having trouble fixing the meshing around the corners. I used an automated mesh(2D) with a few volumetric controls for mesh refinement. My prism layer stretching is 1.265, prism layer total Thickness is 0.15m. Attached is an image of what my meshing is and what i'm trying to achieve. In the attachment Image A is what i got. I am trying to get something similar to image B or anything better.

Thanks in advance

TechnoB
Attached Images
File Type: jpg corners.JPG (50.5 KB, 117 views)
technoB is offline   Reply With Quote

Old   November 1, 2022, 10:16
Default
  #2
New Member
 
Nikolaos Papafilippou
Join Date: Apr 2019
Posts: 25
Rep Power: 7
Nikpap is on a distinguished road
Have you tried using Advancing Layer Mesher instead of Prism Layer Mesher?
technoB likes this.
Nikpap is offline   Reply With Quote

Old   November 2, 2022, 05:11
Default
  #3
New Member
 
McVas
Join Date: Oct 2022
Posts: 17
Rep Power: 3
technoB is on a distinguished road
Thank you for the suggestion. I am unfamiliar with the Advanced layer mesher , i have attempted it and it looks better than before. If at all you have any tips on improving the meshing that will be great.
Attached Images
File Type: png CORNER.PNG (40.9 KB, 87 views)
technoB is offline   Reply With Quote

Old   November 2, 2022, 10:10
Default
  #4
New Member
 
Nikolaos Papafilippou
Join Date: Apr 2019
Posts: 25
Rep Power: 7
Nikpap is on a distinguished road
I am glad it helped. Unfortunately I cannot think of any other tips at the moment besides the classic "play around with your number of layers, layer thickness" etc.

Maybe it would help to check the documentation of the Advancing Layer Mesher. Nonetheless, to me it seems you have quite a good starting point now.
Nikpap is offline   Reply With Quote

Old   November 7, 2022, 07:01
Default
  #5
New Member
 
McVas
Join Date: Oct 2022
Posts: 17
Rep Power: 3
technoB is on a distinguished road
Hi,

Is there a way to fix the corner cells? I feel this may introduce a slight inaccuracy in my results. The attached image is the meshing at the corner.
Attached Images
File Type: jpg corner.jpg (152.1 KB, 60 views)
technoB is offline   Reply With Quote

Old   December 5, 2022, 09:44
Default
  #6
New Member
 
McVas
Join Date: Oct 2022
Posts: 17
Rep Power: 3
technoB is on a distinguished road
Hi,

I just realised that using the advanced layer mesher brought up a complication i'm not sure how to fix. The total prism layer thickness does not match the measured height. i.e., my total prism layer height is 0.353m in the properties , but after executing the mesh it reads 0.07m when I check with the ruler

How would you advise I correct this?
Thanks in advance
technoB is offline   Reply With Quote

Old   December 5, 2022, 11:04
Default
  #7
New Member
 
Nikolaos Papafilippou
Join Date: Apr 2019
Posts: 25
Rep Power: 7
Nikpap is on a distinguished road
Are you using any custom controls in your mesh that might be interfering with you global settings?

Also when using the ruler it is easy to missclick further inside or outside your domain. Are you sure about the value it reads? Also you should make sure you are not measuring close to a corner.
Nikpap is offline   Reply With Quote

Old   December 5, 2022, 12:27
Default
  #8
New Member
 
McVas
Join Date: Oct 2022
Posts: 17
Rep Power: 3
technoB is on a distinguished road
Hi,

Thanks for taking the time to respond. I have uploaded a snip of what I mean. I added a volumteric control to refine areas around the body and refine the wake region, i also customized the surface remesher. I also removed prism layers at the far field boundaries.

I changed the distribution mode from stretch factor to wall thickness, played around with the number of prism layers, there is still no change. I'm not sure what other setting could drastically have such an effect on the height.

However, my previous prism layer mesher had the correct prim layer total height but the mesh was not excellent as the prism layers collapsed at the corners as seen previously in the thread.

Thanks again in advance
Attached Images
File Type: png prsm.PNG (61.0 KB, 54 views)
technoB is offline   Reply With Quote

Old   December 5, 2022, 16:01
Default
  #9
New Member
 
Nikolaos Papafilippou
Join Date: Apr 2019
Posts: 25
Rep Power: 7
Nikpap is on a distinguished road
In your caption you have the total prism layer thickness as 3.53 m not 0.353 m. Could it be that the units are wrong?

If that is not the case have you tried setting an absolute value instead for the thickness instead of a percentage of the base?
Nikpap is offline   Reply With Quote

Old   December 6, 2022, 15:32
Default
  #10
New Member
 
McVas
Join Date: Oct 2022
Posts: 17
Rep Power: 3
technoB is on a distinguished road
Hi,

The previous image was an attempt at increasing the height to see any change from before. I have also tried using an absolute height but it did not change. I have not tried adjusting the prism layers using a surface control yet, not sure if that would work.
technoB is offline   Reply With Quote

Reply

Tags
corners, prism layers, rectangular

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Prism layers retraction around sharp edges Korimbo STAR-CCM+ 1 February 24, 2021 06:44
How to deal with prism layers in sharp trailing edge of the airfoil Rinia STAR-CCM+ 1 March 11, 2019 20:25
[ICEM] How to create prism layers on sharp trailing edges in ICEM CFD (3D Tetra Mesh)? waseeqsiddiqui ANSYS Meshing & Geometry 15 January 30, 2019 10:59
[ICEM] Prism layers distorted near trailing edge of blade-Unstructured Mesh Rohith Giridhar ANSYS Meshing & Geometry 3 June 29, 2015 17:52
ICEM Prism Layer transition between surface with prism layers and one without TWaung ANSYS Meshing & Geometry 2 October 12, 2009 14:56


All times are GMT -4. The time now is 08:21.