CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > ANSYS Meshing & Geometry

[ANSYS Meshing] Meshing time taking too long

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   May 4, 2021, 13:00
Default Meshing time taking too long
  #1
New Member
 
Varshit Jain
Join Date: May 2021
Location: Rome
Posts: 5
Rep Power: 4
Varshit73 is on a distinguished road
Hey,
Im trying to create a mesh for simple flat plate with ramp model for turbulence modelling. Hence i need a mesh density of around 4 million grid points. But my computer has been at it meshing for 6-7 hours now. I did not expect it to take this long. Not sure why.
I am running on Ansys 19.0 and my pc specs are i7 first gen with 24 gb ram with x64 based OS.

Why is it taking so long? What can i do to remedy this?
Varshit73 is offline   Reply With Quote

Old   May 4, 2021, 22:13
Default
  #2
Senior Member
 
Erik
Join Date: Feb 2011
Location: Earth (Land portion)
Posts: 1,166
Rep Power: 23
evcelica is on a distinguished road
Did you manually mesh anything, or are you making it do an auto mesh?
Auto mesh will take a lot more time than a manual mesh.
evcelica is offline   Reply With Quote

Old   May 5, 2021, 04:06
Default
  #3
New Member
 
Varshit Jain
Join Date: May 2021
Location: Rome
Posts: 5
Rep Power: 4
Varshit73 is on a distinguished road
I defined a face sizing, body sizing, inflation layers and tetrahedron method. I am not sure if that is auto meshing or manual
Varshit73 is offline   Reply With Quote

Old   May 5, 2021, 18:17
Default
  #4
Senior Member
 
Erik
Join Date: Feb 2011
Location: Earth (Land portion)
Posts: 1,166
Rep Power: 23
evcelica is on a distinguished road
This still sounds like it is mostly auto mesh.
For example, when I make a nice structured mesh, I slice the part into bodies (same part though) and define everything using edge sizing, sweep methods, etc. This means I could tell you exactly how many elements it will end of having when complete, there isn't much the mesher has to figure out on its own. This is what I call "manual meshing". With just loose mesh definitions, the mesher has to figure out how to mesh these parts on its own, and will take much longer.
evcelica is offline   Reply With Quote

Old   May 6, 2021, 07:34
Default
  #5
New Member
 
Varshit Jain
Join Date: May 2021
Location: Rome
Posts: 5
Rep Power: 4
Varshit73 is on a distinguished road
Ok. so the recommended way is to define everything in small bodies mesh them together and then combine? Would it be better if i used a meshing software like pointwise to develop the mesh entirely? Would it be faster?
Also, if i define all the characteristics of the mesh and then generate in ansys, what would you expect the meshing time if the number of grid points is around 4-5 million? I have attached my model and what i need the mesh to look like
Im a bit new to CFD, so thanks a ton for all the help.
Varshit73 is offline   Reply With Quote

Old   May 6, 2021, 07:35
Default
  #6
New Member
 
Varshit Jain
Join Date: May 2021
Location: Rome
Posts: 5
Rep Power: 4
Varshit73 is on a distinguished road
Quote:
Originally Posted by evcelica View Post
This still sounds like it is mostly auto mesh.
For example, when I make a nice structured mesh, I slice the part into bodies (same part though) and define everything using edge sizing, sweep methods, etc. This means I could tell you exactly how many elements it will end of having when complete, there isn't much the mesher has to figure out on its own. This is what I call "manual meshing". With just loose mesh definitions, the mesher has to figure out how to mesh these parts on its own, and will take much longer.
Ok. so the recommended way is to define everything in small bodies mesh them together and then combine? Would it be better if i used a meshing software like pointwise to develop the mesh entirely? Would it be faster?
Also, if i define all the characteristics of the mesh and then generate in ansys, what would you expect the meshing time if the number of grid points is around 4-5 million? I have attached my model and what i need the mesh to look like
Im a bit new to CFD, so thanks a ton for all the help.
Attached Images
File Type: png Untitled1.png (178.5 KB, 40 views)
File Type: png Untitled.png (20.8 KB, 41 views)
Varshit73 is offline   Reply With Quote

Old   May 6, 2021, 08:01
Default
  #7
Super Moderator
 
flotus1's Avatar
 
Alex
Join Date: Jun 2012
Location: Germany
Posts: 3,397
Rep Power: 46
flotus1 has a spectacular aura aboutflotus1 has a spectacular aura about
With this fairly simple geometry, creating a block-structured hexahedral mesh in Ansys meshing is pretty straightforward. That should also cut down meshing times to a few minutes.
The general idea is to split your geometry into 3 parts, in a way that each part has 6 rectangular faces. Then apply a few bunching laws on the edges, choose hexa dominant as the meshing method, and that's pretty much it.
There should be many tutorials how to do this on youtube. Search "ansys meshing structured mesh"

This forum might also contain some hints, one example: 3D Multiblock Structured Hexahedral Mesh
flotus1 is offline   Reply With Quote

Old   May 6, 2021, 08:07
Default
  #8
New Member
 
Varshit Jain
Join Date: May 2021
Location: Rome
Posts: 5
Rep Power: 4
Varshit73 is on a distinguished road
Quote:
Originally Posted by flotus1 View Post
With this fairly simple geometry, creating a block-structured hexahedral mesh in Ansys meshing is pretty straightforward. That should also cut down meshing times to a few minutes.
The general idea is to split your geometry into 3 parts, in a way that each part has 6 rectangular faces. Then apply a few bunching laws on the edges, choose hexa dominant as the meshing method, and that's pretty much it.
There should be many tutorials how to do this on youtube. Search "ansys meshing structured mesh"
Okay thats what im gonna do now. Create a structured mesh. But i could not find what bunching laws are? And also i need to create another mesh for this model plus protrusions in the bottom face, should i use the same methodology there too?

Thanks a ton
Varshit73 is offline   Reply With Quote

Old   May 6, 2021, 08:13
Default
  #9
Super Moderator
 
flotus1's Avatar
 
Alex
Join Date: Jun 2012
Location: Germany
Posts: 3,397
Rep Power: 46
flotus1 has a spectacular aura aboutflotus1 has a spectacular aura about
It's been many years since I last used Ansys meshing. So I can't help you with any specifics. Watch a few tutorials, browse the forum for similar topics...
flotus1 is offline   Reply With Quote

Old   May 6, 2021, 15:57
Default
  #10
Senior Member
 
Erik
Join Date: Feb 2011
Location: Earth (Land portion)
Posts: 1,166
Rep Power: 23
evcelica is on a distinguished road
Is your simulation 3D or 2D?
If 2D you don't need much thickness, just sweep mesh 1 element thick.
Slice into 3 bodies.
"Create part" to make it a multibody part.
use sweep meshing and mapped face meshing
assign number of divisions to lines (the same # of divisions for lines which will be swept through)
evcelica is offline   Reply With Quote

Reply

Tags
ansys 19.0, meshing advice

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
[General] Extracting ParaView Data into Python Arrays Jeffzda ParaView 30 November 6, 2023 22:00
[Gmsh] gmshToFoam generates patches with 0 faces and 0 points Simurgh OpenFOAM Meshing & Mesh Conversion 4 August 25, 2023 08:58
simpleFoam error - "Floating point exception" mbcx4jc2 OpenFOAM Running, Solving & CFD 12 August 4, 2015 03:20
Star cd es-ice solver error ernarasimman STAR-CD 2 September 12, 2014 01:01
Could anybody help me see this error and give help liugx212 OpenFOAM Running, Solving & CFD 3 January 4, 2006 19:07


All times are GMT -4. The time now is 10:03.