CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > General Forums > Main CFD Forum

Artificial Diffusion

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

Like Tree2Likes
  • 2 Post By FMDenaro

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   May 5, 2020, 10:11
Default Artificial Diffusion
  #1
New Member
 
Mudit Mehta
Join Date: Mar 2020
Posts: 15
Rep Power: 2
Mudit2208 is on a distinguished road
Hello, I want to know how to show the effect of artificial diffusion by using first order Upwind scheme for convective terms?
Mudit2208 is offline   Reply With Quote

Old   May 5, 2020, 11:05
Default
  #2
Senior Member
 
Filippo Maria Denaro
Join Date: Jul 2010
Posts: 5,355
Rep Power: 57
FMDenaro has a spectacular aura aboutFMDenaro has a spectacular aura aboutFMDenaro has a spectacular aura about
Use the linear wave equation, discretize using a first order explicit time integration and write the modified equation
vesp and Mudit2208 like this.
FMDenaro is offline   Reply With Quote

Old   May 5, 2020, 11:15
Default
  #3
New Member
 
Mudit Mehta
Join Date: Mar 2020
Posts: 15
Rep Power: 2
Mudit2208 is on a distinguished road
Thanks for your reply. But i am solving steady state Navier stokes equation for Lid driven cavity problem. I am required to demonstrate the effect of artificial diffusion using first order upwind scheme for convective terms. Could you please help me with this?
Mudit2208 is offline   Reply With Quote

Old   May 5, 2020, 11:29
Default
  #4
Senior Member
 
Filippo Maria Denaro
Join Date: Jul 2010
Posts: 5,355
Rep Power: 57
FMDenaro has a spectacular aura aboutFMDenaro has a spectacular aura aboutFMDenaro has a spectacular aura about
Quote:
Originally Posted by Mudit2208 View Post
Thanks for your reply. But i am solving steady state Navier stokes equation for Lid driven cavity problem. I am required to demonstrate the effect of artificial diffusion using first order upwind scheme for convective terms. Could you please help me with this?



Show the expression of the local truncation error of the discretization of the convective term. What term is present? What is the meaning in terms of the physics you are solving?
FMDenaro is offline   Reply With Quote

Old   May 5, 2020, 19:53
Default
  #5
Senior Member
 
sbaffini's Avatar
 
Paolo Lampitella
Join Date: Mar 2009
Location: Italy
Posts: 1,235
Blog Entries: 19
Rep Power: 30
sbaffini will become famous soon enoughsbaffini will become famous soon enough
Send a message via Skype™ to sbaffini
Two possible ways are:

1) Use second order as well and compare the two

2) Solve for a flow with analytical solution and detect the actual viscosity given by the numerical solution

In both cases it is required to work at fixed mesh size, otherwise the numerical viscosity would change
sbaffini is offline   Reply With Quote

Reply

Tags
navierstokes cfd, python, simple algorithm

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Problem simulating the temperature rise in a composite material (chtMultiRegionFoam) Adam_K OpenFOAM Running, Solving & CFD 2 March 27, 2019 06:51
Moving mesh Niklas Wikstrom (Wikstrom) OpenFOAM Running, Solving & CFD 122 June 15, 2014 06:20
numerical scheme without artificial diffusion artifact mpeti OpenFOAM Running, Solving & CFD 2 October 26, 2011 11:36
Any example of artificial viscosity artificial diffusion in OpenFOAM dbxmcf OpenFOAM Running, Solving & CFD 0 July 28, 2008 20:52
Artificial numerical diffusion Valdemir G. Ferreira Main CFD Forum 8 February 3, 2000 13:31


All times are GMT -4. The time now is 09:16.