# Meshing?

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

 March 7, 2016, 07:52 Meshing? #1 New Member   Alpha Beta Join Date: Mar 2016 Posts: 28 Rep Power: 2 Is meshed area, the area within which the fluid will be flowing? That is my understanding of mesh.. correct me if I'm wrong. If so how do i include obstacles like a baffle plate. I'm attempting to study sloshing in tanks (cylindrical)... any ideas? I want to use gmsh or salome to do that so it's easier.. so how do I design the baffle plate? Will it be a solid within a solid (using Boolean operation to delete mesh where baffle plate is supposed to be)? Cause I intend to get the stress values on the plates as well.

March 7, 2016, 09:16
#2
Member

Alex
Join Date: Jan 2014
Posts: 94
Rep Power: 4
Quote:
 Originally Posted by xoitx Is meshed area, the area within which the fluid will be flowing? That is my understanding of mesh.. correct me if I'm wrong.
that's correct!

Quote:
 Originally Posted by xoitx If so how do i include obstacles like a baffle plate.
those are the areas left out in the meshing, as you wrote with a boolean operation. only the fluid is meshed.

Quote:
 Originally Posted by xoitx Cause I intend to get the stress values on the plates as well.
For this, you would have to implement an FSI (1 way should work). That way, you can project the pressure field of the CFD simulation onto a mechanical model of the baffle and let FEM calculate the stresses. Is that what you are trying to achieve?

Cheers
Alex

 March 7, 2016, 12:10 #3 New Member   Alpha Beta Join Date: Mar 2016 Posts: 28 Rep Power: 2 What I'm trying to achieve is a simulation of what sloshing looks like without a baffle plate and also with a baffle plate but in various orientations/designs so as to get optimum effect. My understanding so far is that I have to do the Boolean thing and get the effect without the actual model so that fluid is sloshing mid-air without any container :O .. then somehow add container later via blender or something... Is this right? And after I get meshed entity.. how do I slosh it about? :P (I have to fill container to a certain percentage.. is there a variable for this? or do I have to keep meshing about?) Any kind of help is appreciated

 March 7, 2016, 12:14 #4 New Member   Alpha Beta Join Date: Mar 2016 Posts: 28 Rep Power: 2 [QUOTE=Kina;588464 For this, you would have to implement an FSI (1 way should work). That way, you can project the pressure field of the CFD simulation onto a mechanical model of the baffle and let FEM calculate the stresses. Is that what you are trying to achieve? Cheers Alex[/QUOTE] Pretty much .. but I'll do that later if I have time .. I could just run a simple stress analysis on the plate for now.

March 8, 2016, 03:06
#5
Member

Alex
Join Date: Jan 2014
Posts: 94
Rep Power: 4
Quote:
 Originally Posted by xoitx What I'm trying to achieve is a simulation of what sloshing looks like without a baffle plate and also with a baffle plate but in various orientations/designs so as to get optimum effect. My understanding so far is that I have to do the Boolean thing and get the effect without the actual model so that fluid is sloshing mid-air without any container :O .. then somehow add container later via blender or something... Is this right? And after I get meshed entity.. how do I slosh it about? :P (I have to fill container to a certain percentage.. is there a variable for this? or do I have to keep meshing about?) Any kind of help is appreciated
I get a little confused with your terminology of 'stress". Do you mean forces or fluid pressure exerted on the baffle plate? In CFD, we don't explicitly design the solids around the fluid. In CFD, there is only fluid or not fluid. You would do "the Boolean thing" and define the face between the baffle plate and the fluid as "baffle wall" and then monitor the pressure and forces of this wall during the calculation.
I strongly recommend reading the damBreak tutorial. This will give you a first idea of what you might want to realize in terms of setup.

 March 11, 2016, 10:48 Help!! #6 New Member   Alpha Beta Join Date: Mar 2016 Posts: 28 Rep Power: 2 Hi Kina I successfully ran the SloshingTank3d tutorial in the interDymFoam folder That is basically what I'm going for.. I tried to make a cylinder mesh with a boolean cut inside using salome. I meshed it and then created a surface group for the whole thing as 'walls' , exported it as unv and used ideasUnvToFoam and setfields and finally interDymfoam. The whole thing worked. But I cant see the moving water inside.. Its just the empty cylinder with a boolean cut inside swaying. Can't I use 'boxtocell' inside a cylinder? How do I half fill the cylinder? I'm assuming it's something other than 'boxTocell' although I don't see how this is a problem.. It should just fall down and splash all over.. right? And is the mesh right? I meshed it in Salome and then created "surface" group and grouped it as 'walls' In paraview it seemed wrong as only the surfaces were meshed.. there was no mesh inside the volume. I tried meshing and grouping as "volume" but the setfields command returns an error.. I'm guessing this method is totally wrong I don't know if its the mesh that's wrong or the setFieldsdict Please do Help. Thanks

March 17, 2016, 14:48
#7
New Member

Alpha Beta
Join Date: Mar 2016
Posts: 28
Rep Power: 2
Hot a better way.. toposetdict contains some useful info on setting up the water phase (alpha.water file).
I'm using
Quote:
 regions ( targetVolumeToCell // Fills volume below given plane { volume 7.86905; normal (0 1 0); // usually in direction of gravity fieldValues ( volScalarFieldValue alpha.water 1 );
to half fill any structure.
In case anyone needed to know :P

 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 [ANSYS Meshing] only automatic meshing works, kazra ANSYS Meshing & Geometry 1 March 9, 2016 02:10 [ANSYS Meshing] Can I use ANSYS Meshing for manual meshing? Kirjain ANSYS Meshing & Geometry 6 November 30, 2015 09:11 KateEisenhower Open Source Meshers: Gmsh, Netgen, CGNS, ... 7 August 3, 2015 10:49 [ANSYS Meshing] Icem meshing queries Mfaizan ANSYS Meshing & Geometry 21 July 30, 2015 23:10 Ken Main CFD Forum 0 September 4, 2003 11:09

All times are GMT -4. The time now is 05:47.