CFD Online Logo CFD Online URL
Home > Forums > FLUENT

Open Channel Flow

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

LinkBack Thread Tools Display Modes
Old   March 13, 2011, 17:36
Default Open Channel Flow
New Member
Join Date: Mar 2011
Posts: 3
Rep Power: 6
ElanMorin is on a distinguished road

I'm currently trying to perform a simple open channel flow simulation using Fluent 6.3.26 and having absolutely no luck. I've tried looking for tutorials online but haven't found any worth mentioning as they don't cover what I'm trying to do.

The current problem I'm trying to solve is a simple geometry as follows: (Link to well known image hosting website)

The picture shows what I expect the results to be and the boundary conditions that I've set.

The length of the model is 2 meters and the height is 0.5 meters. The aim I'm trying to achieve with this simulation is just to get a working open channel flow example.

Starting from opening Fluent, these are the steps I would expect to take:


(Read case)

Define -> Operation Conditions
Tick: gravity -> Y = -9.81
Define -> Models -> Multiphase
Volume of Fluid -> Tick: Open Channel Flow (Implicit)
Define -> Materials
Define Water
Define -> Phases
phase-1: primary-phase -> air
phase-2: primary-phase -> water
Define -> Boundary Conditions:
Inlet: mass-flow-inlet
Mixture: Multiphase -> Tick: Open Channel
Free Surface Level = 0.2
Bottom Level = 0.1
air: Momentum -> Mass Flow-Rate = 1kg/s
water: Momentum -> Mass Flow-Rate = 100kg/s
Outlet: pressure-outlet
Mixture: Multiphase -> Tick: Open Channel
Free Surface Level = 0.1
Bottom Level = 0
Solve -> Initialize -> Init

Solve -> Iterate (1000 iterations)


I've also tried, unsteady flow, different flow rates including zero for both air and water, ticking or unticking open channel flow at the outlet, and adding various turbulence models. Though if you think these to be the problem, please say, as I may have been adding half the right things but missing out crucial components.

I have also tried different mesh densities (9,000 elements to 255,000 elements)

The current results I attain show a contour phase plot of all air.

My question is simply, what have I done wrong? I have been trying to follow the open channel flow user guide notes from Fluent, and (I think) done everything they say, but still get spurious results.

Thanks in advance.
ElanMorin is offline   Reply With Quote

Old   March 14, 2011, 00:56
Join Date: Apr 2009
Location: Pune
Posts: 37
Rep Power: 8
Sushilkumar is on a distinguished road
I presume you are simulating it in 2D.

what fluid heights you have mentioned at the inlet and outlet locations..?
Sushilkumar is offline   Reply With Quote

Old   March 14, 2011, 04:45
New Member
Join Date: Mar 2011
Posts: 3
Rep Power: 6
ElanMorin is on a distinguished road
Thanks very much for the reply!

My apologies, yes it's 2D.

I've set the fluid heights at 0.1m at the inlet and outlet. Does this significantly change the motion of the fluid downstream? At the inlet it would make a difference but I fail to see what setting a height of 0.1m at the outlet achieves.
ElanMorin is offline   Reply With Quote

Old   August 19, 2011, 14:21
seyedashraf's Avatar
Omid Seyedashraf
Join Date: May 2010
Location: Iran
Posts: 41
Rep Power: 7
seyedashraf is on a distinguished road
Send a message via AIM to seyedashraf Send a message via Yahoo to seyedashraf
air: Momentum -> Mass Flow-Rate = 0.0001kg/s

also you have patched the water section , or not mentioned here
you had to define water in adapt=> region => mark and close
after the initialization, patch the marked section
seyedashraf is offline   Reply With Quote

Old   February 25, 2015, 17:26
New Member
Join Date: Nov 2012
Posts: 22
Rep Power: 4
azna is on a distinguished road
how did you patched the water section for this ? for region that is not rectangular. for example trapezoidal
azna is offline   Reply With Quote


fluent 6.3.26, open channel, open channel flow

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
pisoFoam compiling error with OF 1.7.1 on MAC OSX Greg Givogue OpenFOAM Programming & Development 3 March 4, 2011 18:18
Open Channel Flow OffshoreStructuralEnginer CFX 13 August 3, 2010 21:31
Depth averaging in an open channel flow vrpati STAR-CCM+ 1 January 23, 2010 18:23
pressure outlet (open channel flow) Willem Brantegem Main CFD Forum 0 April 3, 2007 09:39
Open Channel flow Boundary khalid FLUENT 1 November 4, 2006 12:53

All times are GMT -4. The time now is 16:11.