Directed Mesh

badger1 · February 28, 2013, 08:50

Hi
I have an aerofoil as shown on the image and I am using a polyhedral mesh.

I wish to create a structured mesh in the region on the wake shown by the box.

I have created a mseh using the directed mesh function. and have meshed the box with the structured mesh.

How do I then mesh the rest of the geometry without creating two meshes that overlap?

thanks

mmntmflx · February 28, 2013, 08:54

There is no picture, and because of this i have no idea.. if you can put, wen can say something.

And why do you use directed mesh option?

badger1 · February 28, 2013, 08:56

Sorry the picture should be attached to this.

I dont really know how else to do it so I thought that a directed mesh would be the best way I am fairly new to starccm+

mmntmflx · February 28, 2013, 09:07

ok. now,

first why do you use a rectangular region? is there any specific reason? if there is no specific situation. You can use rectangular domain.

second, whatever you mesh this domain the overlap does not occur.

third, there is two method to form finer mesh on the wake area.

1. Use trimmed mesh, there is an specific option "trimmer wake refinement". its advance here, if you change mesh size in domain, wake refinement region remeshed automatically. And you only enter wake refinement lenght..

2. Use any mesh, but absolutelu poly mesh and then you can use "volume shape" option. You can use rectangle, conical, spherical or cylindirical shapes in the region whereever you want (rectangle place in your picture). You must specify a mesh size(absolute or relative) and this are will have finer mesh..

Thats all..

badger1 · February 28, 2013, 09:11

I am wanting to create a polyhedral mesh on everything except the area indicated by the rectangle.

I tried a volumetric shape but it just refines the mesh further with a polyhedral mesh not a structured mesh.

How would I go about creating the different meshes? is the wake refinement only avaliable if the whole mesh is trimmer?

thanks

mmntmflx · February 28, 2013, 10:02

if you create different meshes on different areas, then you have to create two different regions.

For your study, you create two mesh continuumi Mesh 1 is Poly, Mesh 2 is Trimmer or other..

But you have to create two discrete region, you have to divide geometrically your refinement area. Later you have to some boundary combine/interface operations to form conformal mesh.

Note : Trimmer mesh cant use multi region applications - for conformal mesh - you can use complete trimmer or polyhedral mesh with appropriate prism layer mesh..

badger1 · March 1, 2013, 11:11

thanks that is very helpful. Do you think there is an easier way to do this?

I esencially just want a structured mesh in the wake region and it to blend nicely with the prism layers and the polyhedral mesh around it.

mmntmflx · March 1, 2013, 14:29

I have to try may be but be sure trimmer meshing model useless in multiregion problems(iif you desire conformal mesh)..

And i dont know more easier way to do it. You can try the seperate the regions and use interfaces between two regions and just try..

Or you will use trimmer mesh everywhere on the region and you will use volume shape. And dont forget if you can use prism layers you see the enough quality meshes near the wall..

And you should try different meshes and differen mesh densities.. May be you dont need the structured mesh in the wake region. You must compare the solutions.. are you sure? you need the structured mesh? or poly mesh outside the wake region? why?

February 28, 2013, 08:50	Directed Mesh	#1
badger1 Member anonymous Join Date: Dec 2012 Posts: 33 Rep Power: 14	Hi I have an aerofoil as shown on the image and I am using a polyhedral mesh. I wish to create a structured mesh in the region on the wake shown by the box. I have created a mseh using the directed mesh function. and have meshed the box with the structured mesh. How do I then mesh the rest of the geometry without creating two meshes that overlap? thanks

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
[ICEM] surface mesh merging problem	everest	ANSYS Meshing & Geometry	44	April 14, 2016 07:41
Inner geometry gets lost exporting mesh from ICEM CFD to CFX-Pre	powpow	CFX	3	December 20, 2012 10:14
[ICEM] Problem making structural mesh on a surface	froztbear	ANSYS Meshing & Geometry	1	November 10, 2011 09:52
[snappyHexMesh] snappyHexMesh won't work - zeros everywhere!	sc298	OpenFOAM Meshing & Mesh Conversion	2	March 27, 2011 22:11
2d irregular grid	Remy	Main CFD Forum	1	December 22, 2008 05:49

February 28, 2013, 08:54		#2
mmntmflx Member Melih Meriç Join Date: Apr 2011 Posts: 46 Rep Power: 15	There is no picture, and because of this i have no idea.. if you can put, wen can say something. And why do you use directed mesh option?

February 28, 2013, 09:07		#4
mmntmflx Member Melih Meriç Join Date: Apr 2011 Posts: 46 Rep Power: 15	ok. now, first why do you use a rectangular region? is there any specific reason? if there is no specific situation. You can use rectangular domain. second, whatever you mesh this domain the overlap does not occur. third, there is two method to form finer mesh on the wake area. 1. Use trimmed mesh, there is an specific option "trimmer wake refinement". its advance here, if you change mesh size in domain, wake refinement region remeshed automatically. And you only enter wake refinement lenght.. 2. Use any mesh, but absolutelu poly mesh and then you can use "volume shape" option. You can use rectangle, conical, spherical or cylindirical shapes in the region whereever you want (rectangle place in your picture). You must specify a mesh size(absolute or relative) and this are will have finer mesh.. Thats all..

February 28, 2013, 09:11		#5
badger1 Member anonymous Join Date: Dec 2012 Posts: 33 Rep Power: 14	I am wanting to create a polyhedral mesh on everything except the area indicated by the rectangle. I tried a volumetric shape but it just refines the mesh further with a polyhedral mesh not a structured mesh. How would I go about creating the different meshes? is the wake refinement only avaliable if the whole mesh is trimmer? thanks

February 28, 2013, 10:02		#6
mmntmflx Member Melih Meriç Join Date: Apr 2011 Posts: 46 Rep Power: 15	if you create different meshes on different areas, then you have to create two different regions. For your study, you create two mesh continuumi Mesh 1 is Poly, Mesh 2 is Trimmer or other.. But you have to create two discrete region, you have to divide geometrically your refinement area. Later you have to some boundary combine/interface operations to form conformal mesh. Note : Trimmer mesh cant use multi region applications - for conformal mesh - you can use complete trimmer or polyhedral mesh with appropriate prism layer mesh..

March 1, 2013, 11:11		#7
badger1 Member anonymous Join Date: Dec 2012 Posts: 33 Rep Power: 14	thanks that is very helpful. Do you think there is an easier way to do this? I esencially just want a structured mesh in the wake region and it to blend nicely with the prism layers and the polyhedral mesh around it.

March 1, 2013, 14:29		#8
mmntmflx Member Melih Meriç Join Date: Apr 2011 Posts: 46 Rep Power: 15	I have to try may be but be sure trimmer meshing model useless in multiregion problems(iif you desire conformal mesh).. And i dont know more easier way to do it. You can try the seperate the regions and use interfaces between two regions and just try.. Or you will use trimmer mesh everywhere on the region and you will use volume shape. And dont forget if you can use prism layers you see the enough quality meshes near the wall.. And you should try different meshes and differen mesh densities.. May be you dont need the structured mesh in the wake region. You must compare the solutions.. are you sure? you need the structured mesh? or poly mesh outside the wake region? why?