CFD Online Logo CFD Online URL
Home > Forums > General Forums > Main CFD Forum

Mac Cormack scheme and use of PML boundary conditi

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

LinkBack Thread Tools Search this Thread Display Modes
Old   January 11, 2002, 04:00
Default Mac Cormack scheme and use of PML boundary conditi
vineet kshirsagar
Posts: n/a
hi i am doing a project aeroacoustic simulation in which i am using Mac Cormack scheme (yes its only 2nd order accurate). i am using linearised euler equations in the primitive form, and forward predictor, backward corrector scheme in 2 Dimensional cartesian grid.and i have a PML domain around my main computaional(from where i get the result). the PML equations i am using r the ones suggested by Mr Fang Q Hu in his paper " on absorbing boundary conditions for linearised euler equations by a perfectly matched layer", in which he splits all the veriables in the main domain(4 variables) into 2 in the pml doamin(thus 8 variables) and adds viscocity terms to the equations. at the PML and main region, i am intrpolating the equations

Now the problem i am facing is that after few (800-900)iterations at the boundary of the main computaional domain on one side the values dip and on the other side they rise... i will like to know if it is because of the reason that i am using such a scheme insteat of some central difference scheme. or there is some other problem.

thanx in advance. vineet
  Reply With Quote

Old   January 13, 2002, 01:46
Default Re: Mac Cormack scheme and use of PML boundary con
Posts: n/a
Dear Vineet,

In Hu's paper, a filter process is necessary, where a forth-order central difference scheme was used. MacCormack scheme is 2-order and dispersive in nature therefore an effective filter is also needed. In addition, you may try the staggered grid to suppress the spurious oscillations.

Hope it's helpful

  Reply With Quote


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

All times are GMT -4. The time now is 10:27.