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-   -   3d free surface open channel modeling (vof) (http://www.cfd-online.com/Forums/fluent/64609-3d-free-surface-open-channel-modeling-vof.html)

hamed_roozegar May 16, 2009 06:10

3d free surface open channel modeling (vof)
 
<H1 style="MARGIN: 12pt 0in 3pt; TEXT-ALIGN: justify">:confused:im tring to model a 3d open channel flow. i dont know if i have modeled correctly.

can anyone check this stages? thanks.

fluent 3ddp

file read case .

grid check.

define models solver ok.

define models multiphase volume of fluid open channel flow ok implicit body force ok.

define models energy not selected ok.

define models viscous k epsilon model standard enhanced wall treatment pressure gradient effects ok .

define materials water liquid copy create.

Define phases phase 1 air, phase 2 water liquid close.

Define operation conditions gravity y coordinate -9.81 specified operation density selected ok.

Define boundary conditions vel in velocity inlet phase mixture set velocity specification method components z velocity 0.25m/s specification method k and epsilon ok.

Define boundary conditions vel in velocity inlet phase 2 multiphase volume fraction 1 ok.

Define boundary conditions pressure outlet pressure outlet phase mixture set specification method k and epsilon ok.

Define boundary conditions pressure outlet pressure outlet phase water multiphase backflow volume fraction 1 ok.

Define boundary conditions pressure up pressure outlet phase mixture set specification method k and epsilon ok. Close.

Solve controls solutions piso algorithm pressure body force weighted ok.

Adapt region x between ( -1.5 ,1.5) , y( 0,2) , z ( -6 , 6) , adapt yes mark close.

Solve initialize initialize init close.

Solve initialize patch volume fraction value 1 patch.

Solve monitors residual plot select ok.

Solve iterate 1000000 iterate.

</H1>

Ralf Schmidt May 16, 2009 06:34

Hi!

I don't know about the specific VOF model settings... but the others look good...

except: you have no grid @ scale ....

And I would turn off the standard fluent convergence check in the residuals menu...

Ralf

zhaopeng May 16, 2009 09:47

you can turn on the open channel flow option in boundary condition panel if you use pressure inlet or mass flow inlet in inlet boundary and pressure outlet or outflow in outlet boundary.

hamed_roozegar May 20, 2009 05:55

it does'nt work. the velocities are much more than real. :confused:

zhaopeng May 20, 2009 10:28

you can define the velocity magnitude in pressure inlet boundary after turning on open channel flow option.

hamed_roozegar May 21, 2009 14:03

thanks. i did it but it looks that the water is vaporing little by little.
the water goes up . it looks like that the gravity is opposite.

zhaopeng May 23, 2009 09:52

How did you set the outllet boundary?

hamed_roozegar May 23, 2009 11:46

outlet boundary:
multiphase : open channel : free surface level between (0,2).

mamadnamaie March 28, 2010 05:27

hi you should put gravity in z direction not y

Philipov March 29, 2010 02:37

Look the mesh quality and I can not see what is the time step of the calculation. VOF method is used often as an unsteady ....

gomane8 April 20, 2011 18:40

are you sur??? to mark!!!!
 
Adapt region x between ( -1.5 ,1.5) , y( 0,2) , z ( -6 , 6) , adapt yes mark close

i think that you have not to mark the region that you have adapt!!! iam not very sur but i hope for those ho read that topic to search and confirme :

gomane8 May 28, 2011 07:05

Quote:

Originally Posted by gomane8 (Post 304469)
Adapt region x between ( -1.5 ,1.5) , y( 0,2) , z ( -6 , 6) , adapt yes mark close

i think that you have not to mark the region that you have adapt!!! iam not very sur but i hope for those ho read that topic to search and confirme :

you are wright .....not to adapt !!!! just MARK......iam sorry

Yapoo December 23, 2011 17:29

Quote:

Originally Posted by hamed_roozegar (Post 216352)
<H1 style="MARGIN: 12pt 0in 3pt; TEXT-ALIGN: justify">:confused:im tring to model a 3d open channel flow. i dont know if i have modeled correctly.

can anyone check this stages? thanks.

fluent 3ddp

file read case .

grid check.

define models solver ok.

define models multiphase volume of fluid open channel flow ok implicit body force ok.

define models energy not selected ok.

define models viscous k epsilon model standard enhanced wall treatment pressure gradient effects ok .

define materials water liquid copy create.

Define phases phase 1 air, phase 2 water liquid close.

Define operation conditions gravity y coordinate -9.81 specified operation density selected ok.

Define boundary conditions vel in velocity inlet phase mixture set velocity specification method components z velocity 0.25m/s specification method k and epsilon ok.

Define boundary conditions vel in velocity inlet phase 2 multiphase volume fraction 1 ok.

Define boundary conditions pressure outlet pressure outlet phase mixture set specification method k and epsilon ok.

Define boundary conditions pressure outlet pressure outlet phase water multiphase backflow volume fraction 1 ok.

Define boundary conditions pressure up pressure outlet phase mixture set specification method k and epsilon ok. Close.

Solve controls solutions piso algorithm pressure body force weighted ok.

Adapt region x between ( -1.5 ,1.5) , y( 0,2) , z ( -6 , 6) , adapt yes mark close.

Solve initialize initialize init close.

Solve initialize patch volume fraction value 1 patch.

Solve monitors residual plot select ok.

Solve iterate 1000000 iterate.

</H1>

salam aqaie hamed
man rooie ie masaleie moshabehe in masaleie shoma kar mikonam
dar morede taeen sharaiete marzi be moshkel bar khordam mishe komakam konid?

mkhodier May 20, 2013 04:29

Did you guys know the problem, if yes, could u please tell me what was it. Thankls

flow_CH June 2, 2013 08:15

Quote:

Originally Posted by hamed_roozegar (Post 216857)
thanks. i did it but it looks that the water is vaporing little by little.
the water goes up . it looks like that the gravity is opposite.

I have this problem too. :(
I am using "Open channel flow" option in inlet and outlet boundaries. It is look like water goes up in pressure inlet boundary.:confused::confused:
Where is the origin of the free surface and bottom. Is it in bottom of any boundary or origin of coordinates?
help me please.

mohammad87 August 26, 2013 02:24

3D water-gas ejector with vof
 
How do we model the two phase (water-gas) ejector with vof in fluent??

I thank for the help..

mohammad87 January 26, 2014 17:16

mixture model
 
Please explain the mixed model for liquid-gas ejector simulation

Mohammad80 March 25, 2016 05:01

3 Attachment(s)
Hi.
In the attached picture I did a simulation of a pier into a channel using FLUENT but the drag force I got is negative. I used a pressure inlet and pressure outlet with giving the water and bottom levels by ticking on the open channel choice. Any tips please?


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