|
[Sponsors] |
inlet/outlet boundary conditions for a forced flow in a channel |
|
LinkBack | Thread Tools | Search this Thread | Display Modes |
September 12, 2011, 10:38 |
inlet/outlet boundary conditions for a forced flow in a channel
|
#1 |
New Member
Davide Cagnoni
Join Date: Jul 2011
Posts: 14
Rep Power: 15 |
hi!
I'm trying to run a simulation about an internal flow in a converging channel, and i am in doubt about the boundary conditions to use: i do not have a fixed mass-flow rate since what i am investigating is the result of a volume force on the fluid flow (therefore i have a source term in the momentum equation...) this force should (and does) pump the fluid towards the narrower section (which is my "outlet") at which i imposed a 0 pressure - 0 stress boudary condition. At first i have imposed the same BC on the other channel edge since i thought the inflow should be free from stress and also at the same "external" pressure - being the motion triggered only by the volume force to which the fluid is exposed - but being my results quite different from what i expected i think something in my opinions is wrong... thanks for every hint anybody would give me |
|
September 13, 2011, 04:41 |
|
#2 |
New Member
Davide Cagnoni
Join Date: Jul 2011
Posts: 14
Rep Power: 15 |
sorry for bumping....
|
|
September 13, 2011, 09:33 |
|
#3 |
Member
Zachariah Swetky
Join Date: Aug 2011
Posts: 36
Rep Power: 15 |
davide_c,
It seems to me that applying a force to the fluid should yield a pressure gradient from the inlet to the outlet. By applying 0 pressure at both the inlet and the outlet are you not nullifying this gradient? Are you specifying total pressure or static pressure at the inlet and outlet? |
|
September 13, 2011, 10:03 |
|
#4 |
New Member
Davide Cagnoni
Join Date: Jul 2011
Posts: 14
Rep Power: 15 |
If i am correct, my pressure object represents static pressure (normalized by the density)
I spent some time thinking about it and realised the same conclusion about the pressure drop, so I switched the pressure condition on inlet to 0-gradient. Still, with this other arrangement i have problems -instabilities- after some time at the outlet. I am thinking about imposing a 0 gradient condition on the whole boundary - which I know phisically not having much sense together wit a no stress condition for U - just to try out... |
|
Tags |
boundary, channel, forced, inlet |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Implementation of boundary conditions for FVM | Tom | Main CFD Forum | 7 | August 26, 2014 06:58 |
Channel flow with cyclic boundary conditions | nzy102 | OpenFOAM Running, Solving & CFD | 0 | April 19, 2007 17:13 |
open channel flow boundary conditions | yan | FLUENT | 0 | July 5, 2005 00:36 |
New topic on same subject - Flow around race car | Tudor Miron | CFX | 15 | April 2, 2004 07:18 |
Pressure boundary conditions of channel flow | Ray | Main CFD Forum | 4 | July 29, 2002 10:08 |