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

some problem about caculation of quadrature

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

Reply
 
LinkBack Thread Tools Display Modes
Old   March 8, 2006, 03:10
Default some problem about caculation of quadrature
  #1
ztdep
Guest
 
Posts: n/a
Hell0:

ervery one !

i want to compute the integeral of some variable over whole domain, the intergral need a high resolution gauss quadrature method, but i only have the varible value on my two dimensional grid points, the gauss quadrature need the value at the gauss quadrature points, then how should i know it.

it is a two diemsional rectangle domain. regards
  Reply With Quote

Old   March 8, 2006, 10:04
Default Re: some problem about caculation of quadrature
  #2
al
Guest
 
Posts: n/a
maybe you should use a spectral method.
  Reply With Quote

Old   March 8, 2006, 10:10
Default Re: some problem about caculation of quadrature
  #3
ztdep
Guest
 
Posts: n/a
can spectral method caculate the integral
  Reply With Quote

Old   March 8, 2006, 14:25
Default Re: some problem about caculation of quadrature
  #4
al
Guest
 
Posts: n/a
you wrote: "..I want to compute the integeral of some variable over whole domain, the intergral need a high resolution gauss quadrature method, but i only have the varible value on my two dimensional grid points, the gauss quadrature need the value at the gauss quadrature points, then how should i know it. "

I am assuming that your solution/ or your points are given in terms of a low order method, i.e. FDM or FVM. Your problem is that you want to use a high order quadrature for computing the integral (I dont know why). Of course, your quadrature point does not coincide with your FD/FV points. So, my suggestion was if you require high accuracy you should consider a high order method for example galerkin spectral method, or variations depending on your problem for computing your solution.

So, by the way why you want to use a gauss quadrature ? if you have your points uniform distributed you can use a rectangular integration rule or equilavents.

  Reply With Quote

Old   March 8, 2006, 17:58
Default Re: some problem about caculation of quadrature
  #5
ztdep
Guest
 
Posts: n/a
thank you very much! i am doing a Galerkin projection onto the POD eigenmode, the projection is a integral, and it is nesessary to evaluate it with a high resolution scheme! the pod eigenmode was obtained from the FVM solutions.

regards

  Reply With Quote

Reply

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
conduction problem venkataramana OpenFOAM 3 December 1, 2013 07:30
UDF compiling problem Wouter Fluent UDF and Scheme Programming 6 June 6, 2012 04:43
area does not match neighbour by ... % -- possible face ordering problem St.Pacholak OpenFOAM 9 November 22, 2011 10:02
natural convection problem for a CHT problem Se-Hee CFX 2 June 10, 2007 06:29
Adiabatic and Rotating wall (Convection problem) ParodDav CFX 5 April 29, 2007 19:13


All times are GMT -4. The time now is 07:42.