CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > FLUENT

rotation velocity of a water wheel and rotating domain

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   November 12, 2014, 11:50
Default rotation velocity of a water wheel and rotating domain
  #1
Senior Member
 
Join Date: Oct 2014
Posts: 124
Rep Power: 12
Ema40 is on a distinguished road
Hy everybody.

I am simulating a water wheel with an angular velocity v [rad/s].

1) I have imposed the velocity v in "cell zone conditions", both in the reference frame, both in the mesh motion.
When I plot "Graphic and Animation-Contours-velocity magnitude", if there is no water inside the wheel, so only air, the velocity w in a certain point must be w=v*R, where R is the distance between the point and the rotation axle. But the plotted velocity is w=2*v*R and I can't understand why. I have to impose only the rotational velocity v in the mesh motion? if yes, why? It is strange because even if the tangential velocity appears to be wrong w=2*v*R, instead the actual one w=v*R, the wheel makes a complete turn of 360°=6.28rad in time=6.28/v, so v is right. How it is possible that w is calculated badly, while the wheel rotates at the right velocity v?

2) If there is no water, the static pressure is only due to the air weight, so it increase from the top of the wheel toward the lowest point of the wheel (since the air is lightweigh the difference of static pressure has to be small, but if I plot it the difference is 300 N/mq!! And the wheel is only 2 m in diameter.

Thank you very much
I hope in some advises
Ema40 is offline   Reply With Quote

Reply

Tags
mesh motion, reference frame, rotating domain, turbine, water wheel

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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 Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Water wheel simulation Ema40 FLUENT 4 November 13, 2014 03:35
Rotating Wheel Example/Information Required scott OpenFOAM 1 March 11, 2012 14:49
Output Pressure reults for rotating wheel. HELP Krishan Parmar Phoenics 0 July 2, 2007 15:11
Rotating bike wheel E. Turner FLUENT 3 October 1, 2006 01:44
Terrible Mistake In Fluid Dynamics History Abhi Main CFD Forum 12 July 8, 2002 10:11


All times are GMT -4. The time now is 12:16.