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

Effect of gravity force in a pipe flow

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

Like Tree2Likes
  • 1 Post By novice
  • 1 Post By novice

Reply
 
LinkBack Thread Tools Display Modes
Old   July 14, 2010, 02:23
Default Effect of gravity force in a pipe flow
  #1
Member
 
novice
Join Date: Nov 2009
Posts: 33
Rep Power: 8
novice is on a distinguished road
Dear All,

It is a very basic question but very important one for me. Does the gravity force has any effect on a flow through a cyllindrical pipe??

Thanks in advance

Novice
novice is offline   Reply With Quote

Old   July 14, 2010, 03:49
Default
  #2
New Member
 
Maciej
Join Date: Dec 2009
Posts: 6
Rep Power: 8
MacWnc is on a distinguished road
In my opinion it has effect on flow for vertical pipe or horizontal pipe with great diameter, also the gravity force depends on density of the fluid.
MacWnc is offline   Reply With Quote

Old   July 14, 2010, 03:56
Default
  #3
Member
 
novice
Join Date: Nov 2009
Posts: 33
Rep Power: 8
novice is on a distinguished road
Hi MacWnc,

Thanks for the reply. If the fluid is water (incompressible) will there be any effect of the gravitational force on the flow.

Regards
novice is offline   Reply With Quote

Old   July 14, 2010, 04:03
Default
  #4
New Member
 
Maciej
Join Date: Dec 2009
Posts: 6
Rep Power: 8
MacWnc is on a distinguished road
Water has great density , so it affect on flow. Your duct is vertical or horizontal? what is the diameter of it?
MacWnc is offline   Reply With Quote

Old   July 14, 2010, 04:21
Default
  #5
Member
 
novice
Join Date: Nov 2009
Posts: 33
Rep Power: 8
novice is on a distinguished road
Hi MacWnc,

The pipe diameter different in different cases. It varies from 48" (1220 mm) to 10" (254 mm). The pipe has a 90 elbow. One case the flow coming from the downwars then enters into an elbow and go toward right side, that means the flow come from a vertical pipe enters into an elbow then enters in to a horizontal pipe (like 6:15 in a clock). and in one other case the pipe has an elbow but it is completely horizontal. In these two cases will the Gravitational force has any effect on the flow??

Thanks again.
rgd likes this.
novice is offline   Reply With Quote

Old   July 14, 2010, 04:32
Default
  #6
New Member
 
Maciej
Join Date: Dec 2009
Posts: 6
Rep Power: 8
MacWnc is on a distinguished road
You should turn on the gravity for every case. It does not increase computational time, so dont bother yourself anymore. the effect of gravity will be greater in horizontal pipe.
MacWnc is offline   Reply With Quote

Old   July 14, 2010, 05:28
Default
  #7
Member
 
novice
Join Date: Nov 2009
Posts: 33
Rep Power: 8
novice is on a distinguished road
Hi MacWnc,
I am activating the gravity in all my simulations. But, irrespective of the fluent simulation, in general i would like to know whether the gravitational force has an effect on the flow through a pipe. If you have any study material on this aspect, can you please forward to me.
Regards
rgd likes this.
novice is offline   Reply With Quote

Old   September 13, 2014, 00:47
Post Effect of gravity missing!
  #8
rgd
New Member
 
Join Date: Dec 2012
Posts: 24
Rep Power: 5
rgd is on a distinguished road
Dear all,

I am simulating the maldistribution through a distributor (with multiple outlets) & I am trying to find the effect of gravity on both orientations: horizontal & vertical. I turned on the gravity in y-direction for horizontal & in z-direction for vertical. But there seems to be no difference at all in my simulations, both are identical!
Nonetheless, the reference I am using states otherwise, also common sense dictates that the simulation in the vertical direction should have less maldistribution.
So what am I forgetting here? is there any other parameter I need to enter in Fluent?

P.S. As a trial I activated the 'Specified Operating Density' option in the 'Operating Conditions' window, under the 'Boundary Conditions', and I set it to the density of my working fluid: water (when I simulate one phase only) & water-vapor (when I am simulating 2 phases)
rgd is offline   Reply With Quote

Old   May 29, 2015, 11:02
Default
  #9
New Member
 
Thota
Join Date: Apr 2014
Posts: 6
Rep Power: 4
Thota is on a distinguished road
I think body forces are critical in your case. Try changing the under-relaxation factors and then check the results.
Thota is offline   Reply With Quote

Reply

Thread Tools
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 On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
steam flow in a pipe driven by a pressure gradient between inlet and outlet SalvoCalvo Main CFD Forum 0 March 11, 2010 07:52
Two-phase air water flow problems by activating Wall Lubrication Force challenger85 CFX 5 November 5, 2009 06:44
The lift force coefficient in bubbly flow Kai Yan Main CFD Forum 1 November 4, 2008 14:54
Pipe flow with obstacle - HELP Min FLUENT 5 April 10, 2007 17:23
Effects of gravity in pipe - pressure distribution Anthony Wachs FLUENT 2 July 25, 2001 07:07


All times are GMT -4. The time now is 23:15.