about open channel simulation in flow-3

 User Name Remember Me Password
 Register Blogs Members List Search Today's Posts Mark Forums Read

 LinkBack Thread Tools Display Modes
 January 18, 2009, 12:38 about open channel simulation in flow-3 #1 Marco Guest   Posts: n/a Dear expert : I want to simulate rectangle shape open channel in flow-3d. I have some questions. 1. When I set boundary conditions. It can set velocities versus time. Can I set fluid depths versus time or set discharge curve versus time? If it can be set where could I do that? 2. What did I set on top boundary condition(Z max) because top boundary is air. Did I set symmetry boundry? If that's true what did I sat anything? 3. There are two fluids in open channel. One is water one is the air. Did I set two fluids in global? If that's true what did I sat anything? Thaks your help!

 January 26, 2009, 13:13 Re: about open channel simulation in flow-3 #2 HC Guest   Posts: n/a 1. Yes, you can also set time-dependent fluid depth/discharge. When you open the boundary dialog, there is a fluid height button. Click on that, and you can put values in the table inside that dialog. Between two neighboring times, the fluid height would be linearly interpolated. The similar procedure also applies to volume flow rate boundaries. In the dialog with volume flow rate option checked, there is a button called "Volume flow rate". Click on that and follow the same steps. 2. If the water is not touching the top boundary in the simulation, yes, you can set the Zmax boundary to symmetry, or you can set it to the pressure boundary with fraction of fluid equal to 0. 3. If there is no strong interaction between the water and the air, meaning the air is not affecting the water flow, you may as well just use one fluid model to simulate the motion of water. In some cases, you may need to study the entrained air and there is air entrainment model available under the physics tab. For some others, users may need to use two-fluid option accordingly and it depends on the cases. zandi likes this.

 February 2, 2009, 12:22 Re: about open channel simulation in flow-3 #3 Fran Guest   Posts: n/a Marco, In a same case we have we have set in the inlet a fixed height and FF=1. In the outlets a static pressure = 0. The upper BC is simmetry.

December 22, 2012, 15:40
#4
Senior Member

Fatema Zandi Goharrizi
Join Date: Mar 2009
Posts: 131
Rep Power: 8
Quote:
 Originally Posted by HC ;93158 1. Yes, you can also set time-dependent fluid depth/discharge. When you open the boundary dialog, there is a fluid height button. Click on that, and you can put values in the table inside that dialog. Between two neighboring times, the fluid height would be linearly interpolated. The similar procedure also applies to volume flow rate boundaries. In the dialog with volume flow rate option checked, there is a button called "Volume flow rate". Click on that and follow the same steps. 2. If the water is not touching the top boundary in the simulation, yes, you can set the Zmax boundary to symmetry, or you can set it to the pressure boundary with fraction of fluid equal to 0. 3. If there is no strong interaction between the water and the air, meaning the air is not affecting the water flow, you may as well just use one fluid model to simulate the motion of water. In some cases, you may need to study the entrained air and there is air entrainment model available under the physics tab. For some others, users may need to use two-fluid option accordingly and it depends on the cases.
can you help me with how finding the amount of air content?! in post processing part

 January 11, 2013, 12:53 #5 New Member   Mahdiar Farhoudi Join Date: Feb 2012 Location: Tehran, Iran Posts: 17 Rep Power: 5 Hi HC, whould you mind tell me what do you mean by "strong interaction between the water and the air, meaning the air is not affecting the water flow" ?? As i read before in an article two-fluid option didn't work for two phases like air & water, because of their great density diffrence. So it was written that we should use one-fluid, activating density evaluation & drift flux in physics tab. but I'm not sure it works or not!! http://hub.hku.hk/bitstream/10722/56029/3/FullText.pdf Last edited by mf_emp; January 11, 2013 at 13:13.

 Thread Tools Display Modes Linear Mode

 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 OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post ElanMorin FLUENT 4 February 25, 2015 17:26 k.baker FLUENT 0 December 3, 2010 04:30 sxhdhi OpenFOAM Running, Solving & CFD 3 May 5, 2009 21:58 yan FLUENT 1 May 21, 2005 00:21 ram Main CFD Forum 5 June 17, 2000 21:31

All times are GMT -4. The time now is 10:33.

 Contact Us - CFD Online - Top