# [GAMBIT] Rotate and revolute possible ?

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 January 4, 2012, 04:38 Rotate and revolute possible ? #1 New Member   Ijaz Join Date: Dec 2011 Location: Singapore Posts: 17 Rep Power: 14 How do i make the part rotate and revolute abt an axis? My problem statement is tool (smaller cylindrical part)needs to rotate by itself as well as rotate around (0,0,0) axis inside another cylinder containing water.I need to see the pressure and velocity variation as the tool moves itself as well as around the axis. Please suggest me how to do it step by step. Also do additional surfaces need to be drawn in gambit so that I can get better display of result in 3d as I need to see the pressure variation of water in the tank at various heights..

 January 4, 2012, 05:01 #2 Super Moderator     Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,297 Rep Power: 41 can you post a sketch of what you want to build? __________________ In memory of my friend Hervé: CFD engineer & freerider

January 4, 2012, 05:31
#3
New Member

Kaushik
Join Date: Dec 2011
Posts: 16
Rep Power: 14
It is similiar to the slotted cylinder problem but I need the cylindrical tool in my case to rotate and revolute. Please help me step by step. Also had a doubt in the meshing...I have multiple corner points when I use the fixed or proximity size function i am not able to concentrate the meshing at the gaps/corners..My fig is as folllows
Attached Images
 kk1.jpg (28.3 KB, 27 views)

 January 4, 2012, 05:35 #4 Super Moderator     Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,297 Rep Power: 41 First the design: what do you want exactly? I don't understand the rotate and volute construction. Do you mean like a spring? __________________ In memory of my friend Hervé: CFD engineer & freerider

 January 4, 2012, 05:41 #5 New Member   Kaushik Join Date: Dec 2011 Posts: 16 Rep Power: 14 No not like a spring.. I used the sliding mesh shown in figure to only rotate my tool (cylinder with slots) but now I have to make the tool also revolute around the centre axis..(0,0,0). The tool is placed eccentrically at position (0,-1.5,0.8). I hope i make my doubt clear to you..

 January 4, 2012, 06:51 #6 Super Moderator     Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,297 Rep Power: 41 so you don't need to construct any geometry. It is only the motion you want to describe? __________________ In memory of my friend Hervé: CFD engineer & freerider

 January 4, 2012, 08:13 #7 New Member   Ijaz Join Date: Dec 2011 Location: Singapore Posts: 17 Rep Power: 14 yes..can we do it in fluent itself or there needs to be some changes in geometry in gambit?

 January 4, 2012, 08:18 #8 Super Moderator     Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,297 Rep Power: 41 Basically you don't to do something in Gambit, except if you want to work with layering __________________ In memory of my friend Hervé: CFD engineer & freerider

 January 4, 2012, 08:34 #9 New Member   Ijaz Join Date: Dec 2011 Location: Singapore Posts: 17 Rep Power: 14 So could you tell an easy method to perform the motion because I give motion to the rotor domain in sliding mesh formulation which to rotate about its own axis. Then for revolution what can be done. Since I wanted both motions simulatneously..is it a tedious process?

 January 4, 2012, 08:40 #10 Super Moderator     Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,297 Rep Power: 41 what is exactly your motion? a cylinder is rotating around its axis, and the axis is also rotating? __________________ In memory of my friend Hervé: CFD engineer & freerider

 January 4, 2012, 10:09 #11 New Member   Ijaz Join Date: Dec 2011 Location: Singapore Posts: 17 Rep Power: 14 yes sir..the axis rotates abt (0,0,0) /

 January 4, 2012, 10:19 Embedded Reference Frames #12 Super Moderator   Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,553 Blog Entries: 6 Rep Power: 54 This problem can be classified as Embedded Reference Frames and can be solved by two methods: 1. Steady State Multiple Reference Frame (MRF) Modeling 2. Sliding Mesh ---> However for this method you need UDF (I shall share this along with sample mesh files, boundary conditions, sample solution and other helping material) First you must decide which method you would prefer. If I were you I would have choose the first method and later on move to later method if needed.

 January 4, 2012, 10:31 #13 Super Moderator   Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,553 Blog Entries: 6 Rep Power: 54 your problem looks like this one?

 January 4, 2012, 13:59 #14 New Member   Ijaz Join Date: Dec 2011 Location: Singapore Posts: 17 Rep Power: 14 thks for your time...yes sir it is similiar to the picture you provided.. i am doing a 3d geometry with submerged cylinder ..ill use steady mrf...can u suggest the methodology ... Last edited by Ijaz; January 4, 2012 at 15:22.

 January 5, 2012, 15:35 #15 New Member   Ijaz Join Date: Dec 2011 Location: Singapore Posts: 17 Rep Power: 14 far...can you give more info on how to embedded ref frame motion?

 January 13, 2012, 12:57 #16 Super Moderator   Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,553 Blog Entries: 6 Rep Power: 54 here is the solution. This problem can also be solved using the sliding mesh, but you need UDF (I have it)

 January 20, 2012, 04:12 #17 New Member   Ijaz Join Date: Dec 2011 Location: Singapore Posts: 17 Rep Power: 14 I did as you said and made my slotted cylinder walls as interfaces but there are some problems..there are more than 18 faces which I need to make as interfaces...is that right? My geometry is attached herewith http://www.mediafire.com/?7uho78575kbfap8 The flow is not observed near the slots...could you help me with the meshing of the volume meshing please..the tool is of r=0.285m and ht 0.4m and slots r=0.02m placed in a tank of r=2.6m,h=3.2. The tool is placed at z=0.8m from top of tank and y=-1.5 Last edited by Ijaz; January 24, 2012 at 01:36.

 January 24, 2012, 19:54 #18 New Member   Ijaz Join Date: Dec 2011 Location: Singapore Posts: 17 Rep Power: 14 Please help me in solving the meshing near the slots because flow near the slots is not differentiated with respect to the other cylindrical surfaces. Kindly help.

 January 25, 2012, 09:07 #19 Super Moderator   Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,553 Blog Entries: 6 Rep Power: 54 Ok, I shall check it today Ijaz likes this.

 January 26, 2012, 23:36 #20 New Member   Ijaz Join Date: Dec 2011 Location: Singapore Posts: 17 Rep Power: 14 Thanks...i am eagerly waiting for your reply..