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boundary conditions in FLUENT VOF for open channel flow |
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March 24, 2011, 05:04 |
boundary conditions in FLUENT VOF for open channel flow
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#1 |
New Member
Gillian
Join Date: Sep 2010
Posts: 15
Rep Power: 16 |
Hi guys,
I have been working on the simulation of flow in a channel through a baffle using VOF FLUENT. I encountered a few problems and would appreciate it if you could please give me some suggestions: Currently I am using two separate inlets for water and air. The BC for air is set as pressure inlet. I have tried 3 types of BC for water (pressure-inlet, mass flow, and velocity - as the velocity is known) but the simulation somehow gave me a flow direction that looks like the water flows from outlet back to the inlet. The outlet is set as 1 outlet (for both water and air) and operated as pressure outlet. The top surface of air is also set as pressure outlet. I am wondering if there is some problems with my current setting ? Your suggestions are very much appreciated. Gillian |
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March 24, 2011, 05:36 |
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#2 |
New Member
mohsen
Join Date: Feb 2011
Posts: 13
Rep Power: 15 |
hi.
you should not separate the inlet or outlet for water and air.it's better to use OPEN CHANNEL FLOW by switch it's toggle on and set the inlet and outlet as PRESSURE INLET/OUTLET one and entered your data.also it's better too use ''explicit'' method {define>models>multiphase.....} good lock. |
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March 26, 2011, 09:03 |
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#3 |
New Member
Gillian
Join Date: Sep 2010
Posts: 15
Rep Power: 16 |
hi momech,
Thanks a lot for the suggestion! |
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April 5, 2011, 01:58 |
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#4 |
New Member
Gillian
Join Date: Sep 2010
Posts: 15
Rep Power: 16 |
Hi,
I tried the simulation with one inlet for the two phase but could not get the results right. The solution still did not converge and another serious issue is the results gave me reverse flow at the inlet. My boundary conditions are: 1. inlet: pressure inlet, with specifying the flow depth at the inlet 2. outlet: pressure outlet, with flow depth specified (which is lower than in the inlet, due to pressure drop across the baffle) 3. upperbound : I have tried either pressure outlet and symmetry. Would appreciate it very much if anyone please give me some suggestions on how to solve the problem of reverse flow at the inlet during the simulation. Indeed, I tried to use velocity inlet as BC for inlet. However, I am a bit confused of how to come up with the volume fraction of water and air respectively (in my physical model, the flow is at 0.04 m/s). Besides, it seemed that with velocity inlet, I could not initialize using open channel initialization. Can anyone give me some suggestions on how should i set velocity inlet BC for open channel ? Thanks a lot! Gillian |
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April 5, 2011, 09:08 |
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#5 |
New Member
mohsen
Join Date: Feb 2011
Posts: 13
Rep Power: 15 |
Hi newcomer
I did the 3D open channel case with cutwater and get acceptable results, it seems that you didn't patch your desired area/volume with water and its velocity after initialize. best regards. |
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April 16, 2013, 19:13 |
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#6 | |
New Member
Moahanad
Join Date: Apr 2013
Posts: 6
Rep Power: 13 |
Quote:
anyone can help me with setting the boundary conditions in the open channel flow? Thanks |
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April 16, 2013, 19:18 |
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#7 |
New Member
Moahanad
Join Date: Apr 2013
Posts: 6
Rep Power: 13 |
did u figure out the problem, if u did, could u help me. Thank you.
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June 2, 2013, 09:32 |
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#8 | |
Senior Member
FHydro
Join Date: Jan 2013
Posts: 197
Rep Power: 13 |
Quote:
I am using "Open channel flow" option in inlet and outlet boundaries. It is look like water goes up in pressure inlet boundary. Where is the origin of the free surface and bottom. Is it in bottom of any boundary or origin of coordinates? help me please. |
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June 3, 2013, 04:07 |
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#9 | |
New Member
Join Date: Jun 2013
Posts: 6
Rep Power: 13 |
Quote:
please read "Heave and Pitch Simulation of Ship hull moving through head sea waves" tutorial |
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June 6, 2013, 15:23 |
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#10 |
New Member
Moahanad
Join Date: Apr 2013
Posts: 6
Rep Power: 13 |
Thank you for replying. Could you please send me the tutorial, I can't find it. Thank you for your help.
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June 10, 2013, 12:19 |
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#11 |
Senior Member
OJ
Join Date: Apr 2012
Location: United Kindom
Posts: 473
Rep Power: 20 |
Can you post you email address? I can sent it across to you.
OJ |
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June 10, 2013, 14:18 |
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#12 |
New Member
Moahanad
Join Date: Apr 2013
Posts: 6
Rep Power: 13 |
mkhdcpu1@yahoo.com Thank you for your help
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June 10, 2013, 14:53 |
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#13 |
Senior Member
FHydro
Join Date: Jan 2013
Posts: 197
Rep Power: 13 |
saeed.azsh88@gmail.com thank you
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July 7, 2013, 05:33 |
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#14 |
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Bhargav
Join Date: Jun 2013
Posts: 6
Rep Power: 13 |
ybhargav93@gmail.com thank u
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July 17, 2013, 03:51 |
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#15 |
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tomo umor
Join Date: Jul 2013
Posts: 7
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tomo.umor@gmail.com thanks for help
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July 22, 2013, 17:37 |
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#16 |
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Derek Foran
Join Date: Jul 2013
Posts: 10
Rep Power: 13 |
servicesamigo@gmail.com If it's still out there, thanks!
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July 29, 2013, 05:38 |
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#17 |
New Member
Join Date: Jul 2013
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July 29, 2013, 12:58 |
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#18 |
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Derek Foran
Join Date: Jul 2013
Posts: 10
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I have not received it yet either, I guess it no longer is out there
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August 10, 2013, 04:46 |
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#19 |
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mostafa shamsi
Join Date: Aug 2013
Location: iran
Posts: 4
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August 25, 2013, 10:05 |
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#20 |
New Member
JAY
Join Date: Jul 2013
Posts: 10
Rep Power: 13 |
I have some problem with my boundary condition that how i utilize the neumann condition(∂φ/∂x = 0) at outlet. Can i select pressure outlet at outlet?
my inlet condition is : flat velocity profile =40m/s Re=1.916*10^5 turbulent intensity=4.5% And Inlet height of duct=5mm I select velocity inlet at inlet because my flow is incompresible. And axis boundary condition applied along the centerline. and no slip condition at wall. pls help me. |
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