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

Implementing boundary condition as additional term in differential equations

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   March 16, 2015, 12:32
Default Implementing boundary condition as additional term in differential equations
  #1
New Member
 
Manuel do Nascimento
Join Date: May 2012
Posts: 14
Rep Power: 14
MdoNascimento is on a distinguished road
Hello,

I am wondering if there is anyone who did something like this (sorry for bad english):

let's say we have a one dimensional heat convection problem dT/dt = a*d²T/dx².

Now let's say one boundary is supposed to be adiabatic -> dT/dx = 0.

The idea: I would like to implement the boundary condition as an additional term in the differential equation with the following method: dT/dt = a*d²T/dx² + A*(dT/dx)

Now the factor A has to have a value equal to zero (or extremely small) in any area, except at (or very near) the adiabatic wall where it has to have a large value. The large value of A then has the function to make sure the boundary condition is satisfied at this area to make the product in the new differential equation equal to zero.

This is just an imaginary example to get the idea. I think this method already exists but I don't know the name or how to find it in a mathematical publication.

Does anyone know a solver / a case where something like this has been done? Or an idea how to implement this in OpenFOAM? I am quite new to this software.

Best regards, and thanks
MdoNascimento is offline   Reply With Quote

Old   March 25, 2015, 12:48
Default
  #2
Member
 
Mat
Join Date: Jan 2012
Posts: 60
Rep Power: 14
Mat_fr is on a distinguished road
Hi Manuel,

I think what you want to do is close to a penalization method, which is part of the family of immersed boundary methods or fictitious domain method. (You will find a lot of article for those methods in literature)

But first of all, why don't you want to use a normal boundary condition for your temperature gradient ?

Best,
Mat
Mat_fr is offline   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
Question about heat transfer coefficient setting for CFX Anna Tian CFX 1 June 16, 2013 07:28
Low Mixing time Problem Mavier CFX 5 April 29, 2013 01:00
Velocity profile boundary condition Tuca FLOW-3D 1 April 23, 2013 13:02
Problems implementing new Boundary Condition diegosene OpenFOAM Running, Solving & CFD 5 October 31, 2011 22:32
asking for Boundary condition in FLUENT Destry FLUENT 0 July 27, 2010 01:55


All times are GMT -4. The time now is 16:19.