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

Buoyancy generated Turbulence flow

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   July 13, 2006, 11:49
Default Buoyancy generated Turbulence flow
  #1
Nitesh
Guest
 
Posts: n/a
Hi all

I am simulating a buoyancy driven flow to compute heat transfer and temperature profile inside a spherical vessel.

My simulations involved high Rayleigh Number of order of 10^7 or higher as I have to find the above parameter at high pressure range. So I have included K-epsilon turbulence model along with Boussinesq approximations.

My problem is, I am still unable to find the parameter c3 Epsilon in the list of turbulence specifying parameter, as mentioned in fluent manual, that affects the allignment of gravity and boundary shear flow.

Kindly help me in finding if

1. If there is any other approach to specify this parameter C3 epsilon than specifying in turbulence parameter panel.

2. Kindly explain the effect of this parameter on the sensitivity of results

3. Is this is due to some error that I might have made in specifying other parameters.

Thanks in advance

Regards Nitesh.
  Reply With Quote

Old   July 13, 2006, 19:58
Default Re: Buoyancy generated Turbulence flow
  #2
Khyati
Guest
 
Posts: n/a
Hey,

I am trying to solve Flow over a heated cylinder in a contra Flow(vertically downward direction) using Fluent, at Re = 130 and Richardson number between 0.0. and 1.0. This arrangement also gives a buoyancy driven flow. I had tried using the Boussineq approximation but didnt work. So I had to use density as a function temperature ands seems to give reasonable results for lower temperatures. But there are complications with the higher temperatures.

What is the Re that you are using? Do you think that at Re=130 and Richardson number =1.0 for a flow over a heated cylinder the flow becomes turbulent?

I also have problems in calculating the Cd. In references do you take the area= radius x depth or dia x depth. I tried taking dia X depth and seeems to give nearly half of what it should. Is there any other way that I could calculate the Cd.

I would really appreciate any help from you.

Thanks Khyati
  Reply With Quote

Reply


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
Turbulence settings for external flow around a kite RobinTU Main CFD Forum 2 July 15, 2011 07:26
Turbulence intensity in fully devloped pipe flow - Reference Shocktrain Main CFD Forum 0 October 14, 2010 07:58
buoyancy driven flow ocy FLUENT 6 December 10, 2004 14:12
buoyancy driven flow + unsteady co2 FLUENT 4 May 6, 2004 12:37
fluid flow fundas ram Main CFD Forum 5 June 17, 2000 22:31


All times are GMT -4. The time now is 07:44.