CFD Online Discussion Forums

CFD Online Discussion Forums (
-   ANSYS Meshing & Geometry (
-   -   [GAMBIT] Rotate and revolute possible ? (

Ijaz January 4, 2012 05:38

Rotate and revolute possible ?
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..

-mAx- January 4, 2012 06:01

can you post a sketch of what you want to build?

kaushik180587 January 4, 2012 06:31

1 Attachment(s)
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

-mAx- January 4, 2012 06:35

First the design: what do you want exactly?
I don't understand the rotate and volute construction.
Do you mean like a spring?

kaushik180587 January 4, 2012 06:41

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..

-mAx- January 4, 2012 07:51

so you don't need to construct any geometry.
It is only the motion you want to describe?

Ijaz January 4, 2012 09:13

yes..can we do it in fluent itself or there needs to be some changes in geometry in gambit?

-mAx- January 4, 2012 09:18

Basically you don't to do something in Gambit, except if you want to work with layering

Ijaz January 4, 2012 09:34

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 it a tedious process?

-mAx- January 4, 2012 09:40

what is exactly your motion?
a cylinder is rotating around its axis, and the axis is also rotating?

Ijaz January 4, 2012 11:09

yes sir..the axis rotates abt (0,0,0) /

Far January 4, 2012 11:19

Embedded Reference Frames
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.

Far January 4, 2012 11:31

your problem looks like this one?

Ijaz January 4, 2012 14:59

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 ...

Ijaz January 5, 2012 16:35

far...can you give more info on how to embedded ref
frame motion?

Far January 13, 2012 13:57

here is the solution. This problem can also be solved using the sliding mesh, but you need UDF (I have it)

Ijaz January 20, 2012 05:12

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 that right? My geometry is attached herewith

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

Ijaz January 24, 2012 20:54

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.

Far January 25, 2012 10:07

Ok, I shall check it today

Ijaz January 27, 2012 00:36

Thanks...i am eagerly waiting for your reply..

All times are GMT -4. The time now is 00:38.