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

how to caculate the Galerkin projection

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   March 15, 2006, 08:46
Default how to caculate the Galerkin projection
  #1
ztdep
Guest
 
Posts: n/a
hell0:

I don not how to caculate the Galerkin projection.

( laplace(T), phi )

Where phi is the basis, and i want to project the laplace(T) onto the phi, but 1), what is the meaning of ( ) , and i have the value of T only at discrete points, then how to caculate it.

regards!
  Reply With Quote

Old   March 15, 2006, 09:34
Default Re: how to caculate the Galerkin projection
  #2
al
Guest
 
Posts: n/a
Let us assume a(x) and b(x) two functions in an interval [0,1]. Then (a,b)=integral a(x) b(x) dx

means the inner product, (dot product), between the functions a and b. This can be considered as a projection of a() into b() and the other way around.

This is much more simple, for the case of simple vectors, e.g. a=[1 0 1] and b=[1 0 0] (a,b) = |a| |b| cos( angle (a,b) )

Equivalent, (laplace(T),phi) means that you want to determine the projection of laplace(T) into phi.

Why do you have only discrete points? Are you using a Galerkin spectral method?

Any way, if you have only T at some points, e.g. T[i] , then you can compute approximately laplace(T) at the same points, laplace(T)[i]. Then you can approximate the inner product as

(laplace(T),phi)= laplace(T)[1] phi[1] Deltax + laplace(T)[2] phi[2] Deltax+ ...

where Deltax is the space between the points.

  Reply With Quote

Old   March 15, 2006, 21:36
Default Re: how to caculate the Galerkin projection
  #3
ztdep
Guest
 
Posts: n/a
Hi,Wed:

thank you for your feedback!

would you like to give me your email address, i have some question!

regards!

  Reply With Quote

Old   March 15, 2006, 23:52
Default Re: how to caculate the Galerkin projection
  #4
Mike
Guest
 
Posts: n/a
See here

http://community.livejournal.com/res....html#comments

Mike
  Reply With Quote

Old   March 16, 2006, 01:03
Default Re: how to caculate the Galerkin projection
  #5
ztdep
Guest
 
Posts: n/a
Mike:

what have you give me! i can not get any information from it? then how to use it
  Reply With Quote

Old   March 16, 2006, 01:49
Default Re: how to caculate the Galerkin projection
  #6
Mike
Guest
 
Posts: n/a
My name is "Michail" and I'm Russian

in Russian it means "BEAR"

http://community.livejournal.com/ru_preved/

Bear is our natianal HERO

  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
Galerkin projection sara2115 Main CFD Forum 0 June 5, 2011 11:57
projection method for helical pipe(3D) ehsan_am86 Main CFD Forum 0 August 14, 2010 22:30
[blockMesh] BlockMeshmergePatchPairs hjasak OpenFOAM Meshing & Mesh Conversion 11 August 15, 2008 08:36
free surface flow and projection methods sylvain Main CFD Forum 2 April 26, 2002 10:45
A Second-Order Projection Method for Incompressibl Ivan Main CFD Forum 5 April 29, 2001 08:27


All times are GMT -4. The time now is 03:48.