Boundar condition for pipe flow

GamFlu · May 10, 2011, 05:28

I am beginner in CFD. I need some help, how to take into consideration the effect of the gravity in vertcial pipeflow (upward flow).

Thanks.

shimmyya · May 10, 2011, 07:07

i guess u can easily set gravity in operating conditions

GamFlu · May 10, 2011, 08:04

Yes that where i need help, do i check in gravity and make -9.8m2/s ... aldo do i need to check in operating density and what vale, I am simulating vertical pipe flow of water

shimmyya · May 11, 2011, 02:22

it depends on ur coordinate system, if ur vertical axis goes up positiv, then jes -9.82 m/s² ..... and this density checkbox u can ignore for water in my opinion

hope i could help u

GamFlu · May 12, 2011, 00:12

Thanks shimmyya for your reply. Yes my cooridnate system is +y upwars i.e. I have taken my reference coordinates (0,0,0) at the top of the pipe.
As I understand I do need to check in the gravity option box and do not need to fill the operating density ... but by default it shows a value of 1.225 .. shoud I make this zero or someother value as far i understood the value subsituted here will be subtracted from fluid density i.e. [rho(fluid) - rho(op density] g.h?

waiting for your reply. Thanks once again

shimmyya · May 12, 2011, 02:05

hi,
just let this "specified operating density" box unchecked, that should be fine.

GamFlu · May 13, 2011, 02:23

Need help, can you plz help ... how to calcuate the pressure drop in pipe flow ... can't seem 2 understand the Fluent output plots .. as values I have do not come anywhere near.

shimmyya · May 16, 2011, 09:44

i dont know if this help u , but u can set probe-points which can read out the data of this points like pressure, velocity ......

could be also good to know what version of FLUENT u use

May 10, 2011, 05:28	Boundar condition for pipe flow	#1
GamFlu New Member Join Date: Mar 2011 Posts: 11 Rep Power: 15	I am beginner in CFD. I need some help, how to take into consideration the effect of the gravity in vertcial pipeflow (upward flow). Thanks.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
CFX mass flow boundary condition	Michele Cagna	CFX	3	February 22, 2007 15:52
Mass flow boundary condition	Renato.	Main CFD Forum	0	July 21, 2006 22:07
mass flow inlet boundary condition	vivian	FLUENT	5	April 21, 2006 06:23
External,incompressible flow boundary condition?	John	Main CFD Forum	0	October 1, 2003 00:00
Mass flow boundary condition	Síle	FLUENT	0	June 12, 2003 07:30

May 10, 2011, 07:07		#2
shimmyya New Member eddy Join Date: Apr 2011 Posts: 8 Rep Power: 15	i guess u can easily set gravity in operating conditions

May 10, 2011, 08:04		#3
GamFlu New Member Join Date: Mar 2011 Posts: 11 Rep Power: 15	Yes that where i need help, do i check in gravity and make -9.8m2/s ... aldo do i need to check in operating density and what vale, I am simulating vertical pipe flow of water

May 11, 2011, 02:22		#4
shimmyya New Member eddy Join Date: Apr 2011 Posts: 8 Rep Power: 15	it depends on ur coordinate system, if ur vertical axis goes up positiv, then jes -9.82 m/s² ..... and this density checkbox u can ignore for water in my opinion hope i could help u

May 12, 2011, 00:12		#5
GamFlu New Member Join Date: Mar 2011 Posts: 11 Rep Power: 15	Thanks shimmyya for your reply. Yes my cooridnate system is +y upwars i.e. I have taken my reference coordinates (0,0,0) at the top of the pipe. As I understand I do need to check in the gravity option box and do not need to fill the operating density ... but by default it shows a value of 1.225 .. shoud I make this zero or someother value as far i understood the value subsituted here will be subtracted from fluid density i.e. [rho(fluid) - rho(op density] g.h? waiting for your reply. Thanks once again

May 12, 2011, 02:05		#6
shimmyya New Member eddy Join Date: Apr 2011 Posts: 8 Rep Power: 15	hi, just let this "specified operating density" box unchecked, that should be fine.

May 13, 2011, 02:23		#7
GamFlu New Member Join Date: Mar 2011 Posts: 11 Rep Power: 15	Need help, can you plz help ... how to calcuate the pressure drop in pipe flow ... can't seem 2 understand the Fluent output plots .. as values I have do not come anywhere near.

May 16, 2011, 09:44		#8
shimmyya New Member eddy Join Date: Apr 2011 Posts: 8 Rep Power: 15	i dont know if this help u , but u can set probe-points which can read out the data of this points like pressure, velocity ...... could be also good to know what version of FLUENT u use