|
[Sponsors] |
June 24, 2010, 15:48 |
Moment around and axis or on a plane
|
#1 |
New Member
Join Date: May 2010
Posts: 9
Rep Power: 15 |
Hello everyone,
I'm trying to have the air tumble in a pipe calculated. I placed a cylindrical coordinate system in the centre of the pipe and need the moment/torque around the Z axis. Through the X-Y planes of the coordinate system I also placed a plane (not shown on the pic). Then I tried to have the generate torque calculated on the plane which was unsuccessful. I then tried another approach. I have created a report --> moment with the parts chosen "out". Here the coordinate system laboratory is chosen which I cant change to cylindrical coordinate system which would probably give me the torque. Can anyone help me to get use of on of the approaches I have taken please. Thank you very much. regards, CS |
|
June 24, 2010, 16:35 |
|
#2 |
Member
Vinicius Girardi
Join Date: Mar 2009
Location: Sao Paulo, Brazil
Posts: 80
Rep Power: 17 |
Just copy the Z direction of your cylindrical coordinate system in the "Axis" field and set the origin in a Moment Report... Go to the Tools->Coordinate system and select your Coord. to get this information...
|
|
June 25, 2010, 15:24 |
|
#3 |
New Member
Join Date: May 2010
Posts: 9
Rep Power: 15 |
Thank you for your reply. I have tried that and I get an result. Is there any way to cross check the result? The thing is I only get a torque if I chose an axis which is not on the centreline of the pipe. Currently Im having Z lying on the centreline. When I set in the report --> moment --> 0.0, 0.0, 1.0, it shows me 0.000Nm. When I switch to 1.0, 0.0, 0.0 I get some torque.
Thanks again |
|
June 25, 2010, 16:43 |
|
#4 |
Senior Member
Join Date: Apr 2009
Posts: 154
Rep Power: 17 |
Does your pipe geometry suggest you should be expecting any tumbling? It might help to plot in-plane (XY) velocities to see what's going on ...
|
|
June 25, 2010, 16:51 |
|
#5 |
New Member
Join Date: May 2010
Posts: 9
Rep Power: 15 |
Yes it does. See the pic http://www.casa-tec.com/Bild1.jpg.
I applied streamlines to see what is happening. As said earlier, around x and y it gives me a moment, not around Z which it should. I have been struggling with this for quite some time. I could upload the file on a server if anyone would be free to check the setting. regards, CS |
|
June 25, 2010, 18:42 |
|
#6 |
Senior Member
Join Date: Apr 2009
Posts: 154
Rep Power: 17 |
Are you running an inviscid simulation?
|
|
June 26, 2010, 07:46 |
|
#7 |
New Member
Join Date: May 2010
Posts: 9
Rep Power: 15 |
Hi sure what is meant by that.
I'm running the "turbulent visocisty ratio" at 10, "turbulence intensity" at 0.05 a "No-Slip" wall conditions. I have the measured mass flow data and the CFD prediction is closer to the testing results when "No-Slip" is set. Pressure applied at the outlet is -2500Pa. |
|
June 26, 2010, 08:41 |
|
#8 |
Member
Vinicius Girardi
Join Date: Mar 2009
Location: Sao Paulo, Brazil
Posts: 80
Rep Power: 17 |
Upload the file and I can take a look...
|
|
June 26, 2010, 08:51 |
|
#9 |
New Member
Join Date: May 2010
Posts: 9
Rep Power: 15 |
Thats great. Please send me your email on c.sansanelli@hotmail.com and Ill give you the link.
Thanks again. |
|
Thread Tools | Search this Thread |
Display Modes | |
|
|