CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Pre-Processing

interFoam, nonuniform alpha for channel flow

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

Like Tree1Likes
  • 1 Post By KTG

LinkBack Thread Tools Search this Thread Display Modes
Old   February 23, 2017, 22:41
Default interFoam, nonuniform alpha for channel flow
Senior Member
Join Date: May 2016
Posts: 119
Rep Power: 10
KTG is on a distinguished road
Hi Foamers,

I am trying to setup a simple test case for channel flow boundary conditions. I would like to have river-like flow, using the interFoam solver. The attached zip contains a case file, where water is invading a square channel, and displacing air (see screenshot). I have two questions:

1) Is there a simple way to set the value of alpha at the boundary to be noninform in space? For example, alpha=1 for y<=.5, alpha=0 for y>.5. This is just a shifted heavyside function of y, but I can't figure out how to implement it. I will eventually be using these boundary conditions with a more complicated geometry, so my goal is to find a way to implement different water heights without having to re-mesh every time. This seems simple enough that I shouldn't have to write a new boundary condition, but I am lost on the implementation. Its ok if the water height is constant in time.

2) In the attached case, I have set pressure and velocity boundary conditions based on what I have read on the forums for stability reasons. In reality, I have measured the velocity, but not the pressure in a river. Why is it ok to set uniform pressures at the boundaries , and how should I choose the actual values? Also, it seems that things are not stable unless I put a little water against the inlet for the initial value. This is not really a problem, but if someone can explain that behavior, I would be very interested.

Attached Images
File Type: jpg channel_flow.jpg (23.1 KB, 40 views)
Attached Files
File Type: zip (7.9 KB, 19 views)
ahparvin likes this.
KTG is offline   Reply With Quote


bounday conditions, channel flow, interfoam, pressure

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Issues on the simulation of high-speed compressible flow within turbomachinery dowlee OpenFOAM Running, Solving & CFD 11 August 6, 2021 06:40
setting a Constant Inlet flow - Interfoam bdh1103 OpenFOAM Programming & Development 10 March 6, 2016 09:29
Interfoam - Real world Geometry with constant inlet flow bdh1103 OpenFOAM Running, Solving & CFD 0 February 10, 2016 14:54
Open channel flow with interFoam sorockin OpenFOAM Running, Solving & CFD 8 October 20, 2013 06:50
Flow meter Design CD adapco Group Marketing Siemens 3 June 21, 2011 08:33

All times are GMT -4. The time now is 16:36.