CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > OpenFOAM Running, Solving & CFD

channelFoam

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

Like Tree5Likes
  • 1 Post By wyldckat
  • 1 Post By wyldckat
  • 1 Post By wyldckat
  • 1 Post By JR22

Reply
 
LinkBack Thread Tools Display Modes
Old   February 27, 2013, 07:08
Default channelFoam
  #1
Member
 
pedroxramos's Avatar
 
Pedro Ramos
Join Date: Mar 2012
Location: Portugal
Posts: 59
Rep Power: 5
pedroxramos is on a distinguished road
Hello there!

I'm doing a simulation of the flow around a cylinder with the solver channelFoam.

something like this: http://openfoamwiki.net/images/1/17/...rf_cylMesh.jpg

Any of you is working with a similar case?

I'm trying to adptate the channel395 example of openfoam but i'm not having success.

Any of you have a tutorial for thys kind of problem? Please, help me.

Regards.
__________________
Pedro Ramos

FEUP, Portugal
pedroxramos is offline   Reply With Quote

Old   February 28, 2013, 16:31
Default
  #2
Super Moderator
 
Bruno Santos
Join Date: Mar 2009
Location: Lisbon, Portugal
Posts: 8,258
Blog Entries: 34
Rep Power: 84
wyldckat is just really nicewyldckat is just really nicewyldckat is just really nicewyldckat is just really nice
Greetings Pedro,

Can you be a bit more specific of what exactly you're trying to do?

Best regards,
Bruno
wyldckat is offline   Reply With Quote

Old   February 28, 2013, 16:44
Default
  #3
Member
 
pedroxramos's Avatar
 
Pedro Ramos
Join Date: Mar 2012
Location: Portugal
Posts: 59
Rep Power: 5
pedroxramos is on a distinguished road
Hello Bruno.

I'm workin in a research project at FEUP, Porto.

We are trying to do a numerical simulation of the flow around a cylinder. Like this: http://www.youtube.com/watch?v=1u-Bx13PRGg

The numerical investigation will be validated agains experimental data of the open channel flow around a pille.

What kind of openfoam solver do you suggest? I'm trying the channelFOAM!

Regards.
__________________
Pedro Ramos

FEUP, Portugal
pedroxramos is offline   Reply With Quote

Old   March 2, 2013, 06:28
Default
  #4
Super Moderator
 
Bruno Santos
Join Date: Mar 2009
Location: Lisbon, Portugal
Posts: 8,258
Blog Entries: 34
Rep Power: 84
wyldckat is just really nicewyldckat is just really nicewyldckat is just really nicewyldckat is just really nice
Hi Pedro,

The solver seems to be a good choice, but it depends on a few more details:
  • What have you already been able to do with OpenFOAM? If you're going directly into this solver, than it's a very big jump. It uses LES and it's one of the slowest kinds of simulations that can be performed for incompressible flows!
  • You can find a simple geometry for a flow around a cylinder in the OpenFOAM Programmers Guide, located in the folder "$WM_PROJECT_DIR/doc/Guides-a4". And more specifically, the case should be available in the "tutorials" sub-folder "basic/potentialFoam/cylinder".
  • You can setup more complex geometries if you use SwiftBlock. Or even use SwiftSnap if you have the channel geometry designed in 3D CAD.
  • Are you going to simulate only the submerged part?
Best regards,
Bruno
wyldckat is offline   Reply With Quote

Old   March 2, 2013, 16:17
Default
  #5
Member
 
pedroxramos's Avatar
 
Pedro Ramos
Join Date: Mar 2012
Location: Portugal
Posts: 59
Rep Power: 5
pedroxramos is on a distinguished road
Hello Bruno!

I changed my plans. I think I should use the interFoam solver, using the VOF method. I have no relevant experience with OpenFOAM

I already build the 3D mesh with blockMesh.

I need to use LES model because I want compare the results obtained by Fluent.

Do you think interFoam is a good idea?

Thank you so much, Bruno.

Best regards.
__________________
Pedro Ramos

FEUP, Portugal
pedroxramos is offline   Reply With Quote

Old   March 2, 2013, 20:16
Default
  #6
Super Moderator
 
Bruno Santos
Join Date: Mar 2009
Location: Lisbon, Portugal
Posts: 8,258
Blog Entries: 34
Rep Power: 84
wyldckat is just really nicewyldckat is just really nicewyldckat is just really nicewyldckat is just really nice
Hi Pedro,

At first I didn't even think that VOF supported LES... but then I remembered that the tutorials folder does have 3 kinds: "laminar", "ras" and "les".

I don't know which specific version of OpenFOAM you're using, but if you've got 2.1.1 installed, have a look into this tutorial that 2.1.x has got: https://github.com/OpenFOAM/OpenFOAM...s/waterChannel
You can then try and compare the case setup with the tutorial "multiphase/interFoam/les/nozzleFlow2D".

I honestly am not sure of what else to suggest to you. The rule of thumb with OpenFOAM is to gradually work your way up from a simple case to the target case. So try to keep the geometry as simple as possible to start with.
Starting with icoFoam, simpleFoam and/or pimpleFoam would help you get the feeling for how OpenFOAM works...
But if you want to stick to interFoam, then I suggest that you do some simple cases similar to your target case, starting with laminar, then RAS and finally LES, always comparing with Fluent if possible, so that you can get a good feeling on how things work on OpenFOAM. This of course is if and only if you feel more at ease with Fluent

In addition, do not switch to parallel mode until you really need it! OpenFOAM's VOF in parallel requires some additional calibration of the "fvSchemes" file. Searching the forum for this information should bring up some possible solutions.

Best regards,
Bruno
pedroxramos likes this.
wyldckat is offline   Reply With Quote

Old   April 11, 2013, 06:01
Default
  #7
Member
 
pedroxramos's Avatar
 
Pedro Ramos
Join Date: Mar 2012
Location: Portugal
Posts: 59
Rep Power: 5
pedroxramos is on a distinguished road
Hello again!

I'm using the interFoam solver and I got tihis:
https://dl.dropboxusercontent.com/u/...ier9abril3.avi

I have a problem in the outlet. What boundary condition do you suggest?

Best regards.
__________________
Pedro Ramos

FEUP, Portugal
pedroxramos is offline   Reply With Quote

Old   April 11, 2013, 09:51
Default
  #8
Super Moderator
 
Bruno Santos
Join Date: Mar 2009
Location: Lisbon, Portugal
Posts: 8,258
Blog Entries: 34
Rep Power: 84
wyldckat is just really nicewyldckat is just really nicewyldckat is just really nicewyldckat is just really nice
Hi Pedro,

Are you talking about the detail where the water level seems to reduce on the outlet only?

And what boundary conditions are you currently using? Are they identical (on the outlet) to the ones provided in the tutorial "waterChannel"?

Have you confirmed if the gravity "constant/g" is pointing in the right way?

By the way, I don't know if you have seen the following website: http://folk.ntnu.no/nilsol/cases/openfoam/ - it's geometrically different from what you're doing, but the type of simulation is similar....

Best regards,
Bruno
pedroxramos likes this.
wyldckat is offline   Reply With Quote

Old   April 20, 2013, 14:06
Default
  #9
Super Moderator
 
Bruno Santos
Join Date: Mar 2009
Location: Lisbon, Portugal
Posts: 8,258
Blog Entries: 34
Rep Power: 84
wyldckat is just really nicewyldckat is just really nicewyldckat is just really nicewyldckat is just really nice
Hi Pedro,

I know that you've been able to go further on this topic, at least from what I've seen from this thread: Channel flow using InterFOAM

But I'm posting here about a very recent thread I've seen just now that might be useful to you: open channel flow

Good luck!
Bruno
pedroxramos likes this.
wyldckat is offline   Reply With Quote

Old   April 23, 2013, 05:33
Default
  #10
Member
 
pedroxramos's Avatar
 
Pedro Ramos
Join Date: Mar 2012
Location: Portugal
Posts: 59
Rep Power: 5
pedroxramos is on a distinguished road
Thanks Bruno!

Right now, the problem is the inlet zone.

As you can see here ( http://d.pr/i/yhog ) the water goes up in front of the inlet...

Regards.
__________________
Pedro Ramos

FEUP, Portugal
pedroxramos is offline   Reply With Quote

Old   April 26, 2013, 05:54
Default
  #11
Member
 
pedroxramos's Avatar
 
Pedro Ramos
Join Date: Mar 2012
Location: Portugal
Posts: 59
Rep Power: 5
pedroxramos is on a distinguished road
Hello Bruno.

Do you know why the no slip condition causes this problem?


LIke it has been said here: I built a artificial inlet block with full slip condition in the walls and I got this


any suggestion?
__________________
Pedro Ramos

FEUP, Portugal
pedroxramos is offline   Reply With Quote

Old   April 26, 2013, 13:19
Default
  #12
Senior Member
 
Matthew Denno
Join Date: Feb 2010
Posts: 137
Rep Power: 7
mgdenno is on a distinguished road
Hi Pedro,

Are you initializing the velocity field with setFields? I have seen that kind of wave when the inlet BC does not match the internal field.

Matt
mgdenno is offline   Reply With Quote

Old   April 26, 2013, 19:55
Default
  #13
Super Moderator
 
Bruno Santos
Join Date: Mar 2009
Location: Lisbon, Portugal
Posts: 8,258
Blog Entries: 34
Rep Power: 84
wyldckat is just really nicewyldckat is just really nicewyldckat is just really nicewyldckat is just really nice
Greetings to all!

There is another possibility: the initial pressure fields might be incorrectly defined. Check the following thread for more information: dambreak tutorial's weird velocity field. - more specifically, check post #7

Best regards,
Bruno
wyldckat is offline   Reply With Quote

Old   April 29, 2013, 17:51
Default
  #14
Super Moderator
 
Bruno Santos
Join Date: Mar 2009
Location: Lisbon, Portugal
Posts: 8,258
Blog Entries: 34
Rep Power: 84
wyldckat is just really nicewyldckat is just really nicewyldckat is just really nicewyldckat is just really nice
Quick note: I found today the boundary condition:
Code:
variableHeightFlowRateInletVelocityFvPatchVectorField
I saw it on the list for "Inlet Boundary Conditions": http://foam.sourceforge.net/docs/cpp/a09425.html
Perhaps that boundary condition can help in not injecting too much water into the domain? I haven't re-checked the boundary conditions discussed on the related threads, to see if this is the one already being used...
wyldckat is offline   Reply With Quote

Old   May 8, 2013, 06:27
Default
  #15
Senior Member
 
JR22's Avatar
 
Jose Rey
Join Date: Oct 2012
Posts: 122
Rep Power: 8
JR22 will become famous soon enough
Hi Pedro,

There was recent post that might interest you. It looks like a similar problem as the one you were having:

http://www.cfd-online.com/Forums/ope...t-k-omega.html
pedroxramos likes this.
JR22 is offline   Reply With Quote

Reply

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
p equation solver in channelFoam cheng1988sjtu OpenFOAM Running, Solving & CFD 0 September 6, 2012 17:55
Pressure gradient, channelFoam libra OpenFOAM 4 July 11, 2012 00:40
Error in channelFoam Run in parallel dhruv OpenFOAM 3 March 2, 2012 06:36
perturbation in channelFoam? cheng1988sjtu OpenFOAM Running, Solving & CFD 5 November 2, 2011 16:36
channelFoam for a 3D pipe AlmostSurelyRob OpenFOAM 3 June 24, 2011 13:06


All times are GMT -4. The time now is 01:27.