# [ICEM] Meshing of a pipe with a helix structure help needed

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

 November 30, 2017, 08:10 Meshing of a pipe with a helix structure help needed #1 New Member   Thijs Join Date: Nov 2017 Posts: 29 Rep Power: 2 Hello people, For my master thesis I study fully-developed flows in pipes with a helix structure. The CFD analysis will be done in openFoam and the meshing the geometry using ICEM CFD 18.2 . The flow-domain (geometry) is first drawn using Solidwork and import in ICEM CFD using import model function. My first thought was that I have to create a structured grid using hexahedral elements. So I used in ICEM the create block utility and associated edges to curves at both inlet and outlet. The following step I did was using ogrid and then pre-mesh. This is bassically the way to go for creating a structured grid for a pipe, but my mesh fails in accurately capturing the helix geometry. My question is: is a structured hexahedral mesh possible? Or should I use something else. Or should I consider using an unstructured mesh? Kind regards, Thijs

November 30, 2017, 13:29
#2
Senior Member

Join Date: Feb 2013
Location: Germany
Posts: 199
Rep Power: 17
Your blocking does not respect the geometry of the helix at all. This why you get bad elements there. You have to account for the helix geometry by doing further splits associations and so on. I guess it would be rather painful to do a full 3D blocking for the whole geometry.

My idea is to try this one with the extrusion tool. So you begin with 2D blocking or mesh a e.g. the inlet and afterwards extrude with combined rotation and translation, which is possible in ICEM. Your extrusion parameters then have to fit your geometric parameters of the helix.

I took two quick shots at it, see attachments. First one is to start with a real easy blocking for the upper surface. After converting to unstructured mesh, the mesh is smoothed with orthogonality tool to improve the mesh in the small "bump region". Another strategy would be to improve the blocking itself. This is followed directly by the extrusion.

The second try starts with a unstructured quad dominant mesh. You can use the "curve mesh setup" parameters to create some kind of boundary layers. The rest is exactly the same procedure.
Attached Images
 helix2d.jpg (112.2 KB, 26 views) helix3d_1.jpg (121.4 KB, 25 views) helix3d_2.jpg (123.6 KB, 26 views) helix_unstr1.jpg (115.1 KB, 23 views) helix_unstr2.jpg (124.2 KB, 25 views)

November 30, 2017, 17:27
#3
New Member

Thijs
Join Date: Nov 2017
Posts: 29
Rep Power: 2
Quote:
 Originally Posted by kad Your blocking does not respect the geometry of the helix at all. This why you get bad elements there. You have to account for the helix geometry by doing further splits associations and so on. I guess it would be rather painful to do a full 3D blocking for the whole geometry. My idea is to try this one with the extrusion tool. So you begin with 2D blocking or mesh a e.g. the inlet and afterwards extrude with combined rotation and translation, which is possible in ICEM. Your extrusion parameters then have to fit your geometric parameters of the helix. I took two quick shots at it, see attachments. First one is to start with a real easy blocking for the upper surface. After converting to unstructured mesh, the mesh is smoothed with orthogonality tool to improve the mesh in the small "bump region". Another strategy would be to improve the blocking itself. This is followed directly by the extrusion. The second try starts with a unstructured quad dominant mesh. You can use the "curve mesh setup" parameters to create some kind of boundary layers. The rest is exactly the same procedure.

Thank you for you tips and your effort for spending some time figuring out my problem. I will try this the first thing in the morning and I will report back with my experience.

Kind regards,

Thijs

 Thread Tools Display Modes Linear Mode

 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 OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post sidharth9426 ANSA 3 March 6, 2016 13:40 KateEisenhower Open Source Meshers: Gmsh, Netgen, CGNS, ... 7 August 3, 2015 11:49 tomokus OpenFOAM Meshing & Mesh Conversion 0 May 5, 2014 09:38 [ICEM] ICEM PIPE bend meshing firavia ANSYS Meshing & Geometry 3 December 23, 2012 10:29 jenright OpenFOAM Native Meshers: blockMesh 0 August 22, 2009 09:58

All times are GMT -4. The time now is 08:09.