# convective boundary condition

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

 LinkBack Thread Tools Display Modes
 January 25, 2008, 09:08 convective boundary condition #1 Mani Guest   Posts: n/a Hi Can anyone tell me what on earth is convective boundary condition and how can i impose it at the outlet of my model. Thanks Mani

 January 28, 2008, 18:24 Re: convective boundary condition #2 Glenn Horrocks Guest   Posts: n/a Hi, It is normally used on a wall boundary condition to model heat transfer from the wall. It is not usually used at outlets. Glenn Horrocks

 January 28, 2008, 18:36 Re: convective boundary condition #3 Mani Guest   Posts: n/a Well in the paper that i have infront of me they have imposed this BC at the outlet. How can i use it in CFX anyway. Mani

 January 29, 2008, 19:33 Re: convective boundary condition #4 Glenn Horrocks Guest   Posts: n/a Hi, I have no idea. I can't see how imposing a convective heat transfer condition on an outlet can have any physical basis. The fluid exiting an outlet depends on the temperature upstream. Glenn Horrocks

 January 29, 2008, 19:34 Re: convective boundary condition #5 Glenn Horrocks Guest   Posts: n/a Are you sure they were not applying a thermal radiation boundary condition? You can apply this type of boundary on an outlet in CFX. Glenn Horrocks

 January 30, 2008, 04:29 Re: convective boundary condition #6 Andreas Guest   Posts: n/a Convection means something (mass, momentum, heat, concentration) is transported by the fluid; this is described by the term "div(rho u Phi)" where rho is density, u is velocity and Phi is what is transported. CFX has this convective boundary condition at outlets: for mass and momentum if you set pressure there, and for heat and concentrations this is automatically set (you cannot choose e.g. a temperature at an outlet). There comes a difficulty if pressure fluctuations reach the outlet since they can be reflected there so that the outlet is not fully "convective"; for this, try the beta feature "non-reflecting boundary conditions".

 January 30, 2008, 07:13 Re: convective boundary condition #7 Mani Guest   Posts: n/a Thank you Glenn & Andreas. How can i use "non-reflecting boundary condition" which i suppose is same as "convective BC". The purpose in either case would be to prevent pressure fluctuations reflecting back in flow domain right. Mani

 February 2, 2008, 17:25 Re: convective boundary condition #8 Mani Guest   Posts: n/a Ok i understand now what you meant Andreas. Thank you Mani

 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 HMR CFX 3 March 6, 2011 21:10 andrea_barbera OpenFOAM Running, Solving & CFD 4 March 4, 2010 05:36 garni FLUENT 0 September 25, 2005 13:00 michele OpenFOAM Other Meshers: ICEM, Star, Ansys, Pointwise, GridPro, Ansa, ... 2 July 15, 2005 04:15 STN Main CFD Forum 5 May 29, 2002 08:47

All times are GMT -4. The time now is 10:55.

 Contact Us - CFD Online - Top