CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM

roughness in shallowWaterFoam

Register Blogs Community New Posts Updated Threads Search

Like Tree1Likes
  • 1 Post By haze_1986

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   November 9, 2011, 05:46
Default roughness in shallowWaterFoam
  #1
WSc
New Member
 
Wolfgang Schanderl
Join Date: Nov 2011
Location: Munich
Posts: 2
Rep Power: 0
WSc is on a distinguished road
Hallo everybody,

I want to do an open-channel simulation with shallowWaterFoam.
How can I define the bed-roughness? Or do I have to model it somehow?

Regards,
Wolfgang
WSc is offline   Reply With Quote

Old   July 16, 2013, 22:51
Default Are you looking to model a free-surface flow?
  #2
New Member
 
David Jessop
Join Date: Jul 2013
Posts: 5
Rep Power: 13
dai_bach is on a distinguished road
Hi,

This reply may come far too late for the original post but I hope it may help other openfoam users. I've been trying to model certain classes of free-surface gravity currents for which the horizontal length scale (x and/or y) is much larger than the vertical scale (z). In this framework, vertical accelerations are small compared to gravity, and the conservation equations can be depth averaged which leads to what are often called the shallow water equations. For this reason, I started to investigate the shallowWaterFoam solver. However, as is described in

HTML Code:
http://www.tfd.chalmers.se/~hani/kurser/OS_CFD_2010/johanPilqvist/johanPilqvistReport.pdf
this solver has been written for atmospheric/oceanic flows where the depth (z) is large compared to the Earth's radius. Furthermore, the top and bottom stresses are assumed to be zero. Hence, as is, this solver cannot be used to treat the kind of problem that I've described above. However, with modifications to the equation set in shallowWaterFoam.C, the same files can be used to tackle these classes of problems via a finite volume method.
dai_bach is offline   Reply With Quote

Old   July 22, 2013, 15:10
Default
  #3
Member
 
Haomin Yuan
Join Date: Jan 2012
Location: Madison, Wisconsin, USA
Posts: 59
Rep Power: 14
yhaomin2007 is on a distinguished road
I think you can just use a rough wall function. You may look it up in turbulence model wall function source file.
yhaomin2007 is offline   Reply With Quote

Old   July 22, 2013, 15:31
Default
  #4
New Member
 
David Jessop
Join Date: Jul 2013
Posts: 5
Rep Power: 13
dai_bach is on a distinguished road
That would mean that the "rough wall" would be one of the "frontAndBack faces". I don't think that would work as the domain is only one-cell thick in the depthwise direction, but I could be wrong.
dai_bach is offline   Reply With Quote

Old   September 2, 2013, 04:58
Default
  #5
Senior Member
 
Join Date: Jul 2011
Posts: 120
Rep Power: 15
haze_1986 is on a distinguished road
you are right. it would not work since it is only one cell thick. In depth averaged models the wind and bed stresses act as souce and sink to the momentum equations. I am currently working on this.
cfdopenfoam likes this.
haze_1986 is offline   Reply With Quote

Old   September 4, 2013, 10:03
Default
  #6
Member
 
Andreas Ruopp
Join Date: Aug 2009
Location: Stuttgart / Germany
Posts: 31
Rep Power: 17
andyru is on a distinguished road
hi,
for bottom roughness you just have to impose an additional source. I did that already and that works brilliantly. It is easy:

Code:
...=lambda*hU
Best,

andy
andyru is offline   Reply With Quote

Old   September 24, 2013, 03:49
Default
  #7
Senior Member
 
Join Date: Jul 2011
Posts: 120
Rep Power: 15
haze_1986 is on a distinguished road
Quote:
Originally Posted by andyru View Post
hi,
for bottom roughness you just have to impose an additional source. I did that already and that works brilliantly. It is easy:

Code:
...=lambda*hU
Best,

andy
Hi Andy, did you include this in the hUEqn, momentumPredictor or inside the piso loop?
haze_1986 is offline   Reply With Quote

Old   September 24, 2013, 05:33
Default
  #8
Member
 
Andreas Ruopp
Join Date: Aug 2009
Location: Stuttgart / Germany
Posts: 31
Rep Power: 17
andyru is on a distinguished road
According to Jasak PhD http://powerlab.fsb.hr/ped/kturbo/Op...jeJasakPhD.pdf
I added it to momentum predictor as well as in piso-loop.
andyru is offline   Reply With Quote

Old   September 24, 2013, 06:09
Default
  #9
Senior Member
 
Join Date: Jul 2011
Posts: 120
Rep Power: 15
haze_1986 is on a distinguished road
Quote:
Originally Posted by andyru View Post
According to Jasak PhD http://powerlab.fsb.hr/ped/kturbo/Op...jeJasakPhD.pdf
I added it to momentum predictor as well as in piso-loop.
Can you show me how it can be implemented in both momentum predictor and pisoloop? I have a couple of term that I need to add in shallowWaterFoam.

Last edited by haze_1986; October 3, 2013 at 05:42.
haze_1986 is offline   Reply With Quote

Old   October 1, 2013, 02:34
Default
  #10
Senior Member
 
Join Date: Jul 2011
Posts: 120
Rep Power: 15
haze_1986 is on a distinguished road
Fixed, thanks

Last edited by haze_1986; October 3, 2013 at 05:43.
haze_1986 is offline   Reply With Quote

Old   August 28, 2023, 06:23
Default the roughness
  #11
New Member
 
Join Date: Aug 2023
Posts: 8
Rep Power: 3
Kdelavy is on a distinguished road
Hi everyone,

I am trying to simulate a river with openfoam, using the shallowWaterFoam solver. Is the solver still not considering bottom roughness? How may I add the manning roughness number in the simulation then? Thanks a lot in advance.
Kdelavy is offline   Reply With Quote

Reply

Tags
open channel flow, roughness, shallow water


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
nutRoughWallFunction and Surface Roughness Documented AlanR OpenFOAM Programming & Development 64 January 6, 2024 08:13
Laminar flow and wall roughness junbbung FLUENT 2 November 26, 2022 22:22
Surface roughness in Flow-3d Marco FLOW-3D 3 June 3, 2018 03:15
NACA standart roughness DAK565656 Main CFD Forum 2 August 24, 2005 01:47
Roughness adaptation in CFX 4.4 Bart CFX 1 May 2, 2003 09:32


All times are GMT -4. The time now is 06:34.