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

Capturing the onset of Convection for Rayleigh benard convection with openfoam

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   April 16, 2018, 10:27
Default Capturing the onset of Convection for Rayleigh benard convection with openfoam
  #1
Member
 
a
Join Date: Oct 2014
Posts: 49
Rep Power: 6
cfd@kgp is on a distinguished road
I was trying to capture the critical Rayleigh number using Openfoam buoyantBoussinesqPimpleFoam?


However, I am unsuccessful to get the onset close to Ra_c= 1708; as one has to perturb the initial field with the correct scale.



Openfoam gives the onset some were inbetween Ra = 3000 to 8000 when I dont apply any disturbances in my initial field. Also after setting fluctuations (described below) in the initial temperature field I am not getting correct Rayleigh numbers.



I am starting with the linear conduction temperature profile and superimposing a sinosidal function as a disturbance as ----> 0.1*sin(pi*x)*sin(2*pi*y) .Here, (0.1) is the amplitude of the perturbation where 0.1 is dimensionless value (i.e., 10 % of T_h -T_c)



I have tried 2d simulations for a wide aspect ratio case (5:1) with periodic boundary conditions in x-axis, with central differencing scemes for both convective and diffussive terms


Experts please share your experience/suggesstion regarding this?



Waiting for earliest positive response from anyone.


Thanks in advance
cfd@kgp is offline   Reply With Quote

Reply

Tags
buoyantpimplefoam, onset of convection, openfoam 4, rayleigh number, rayleigh-benard

Thread Tools
Display Modes

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 On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
OpenFOAM Training Jan-Apr 2017, Virtual, London, Houston, Berlin cfd.direct OpenFOAM Announcements from Other Sources 0 September 21, 2016 12:50
benard convection samik FLUENT 0 April 19, 2008 16:22
benard convection samik FLUENT 0 April 2, 2008 17:41
Instability at the onset of natural convection Magherbi Main CFD Forum 0 October 23, 2002 10:53
Instability at the onset of natural convection Magherbi Main CFD Forum 0 October 23, 2002 08:19


All times are GMT -4. The time now is 04:19.