# some problem about the integral

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

 July 12, 2006, 07:58 some problem about the integral #1 ztdep Guest   Posts: n/a Sponsored Links Hi: I have some problem about the integral. if i have a function F(kexi,eta), now, the inverse problem algorithm need the integral of the F over the whold spacedomain, so i expressed it as int(F)dkexi deta but it should expressed as int(F) J dkexi deta where J is the Jacobian coefficient. so why should i include the J in the integral regards

 July 12, 2006, 08:54 Re: some problem about the integral #2 Mani Guest   Posts: n/a the jacobian relates the absolute coordinate system (say x, y, z) to the local coordinate system (say xi, eta, zeta). what you really want to do is to integrate over the absolute space, so your local "dxi, deta, dzeta" vector has to be multiplied by the jacobian matrix to get "dx, dy, dz". absolute and local coordinates may differ in direction (e.g. with a local curvilinear system) and/or may have different scales (normalized local coordinates).

 July 13, 2006, 11:50 some problem about the integral #3 m. malik Guest   Posts: n/a Just because J=J(exi,eta).

 Thread Tools Display Modes Linear Mode

 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 OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post JonW OpenFOAM 3 February 23, 2013 21:41 St.Pacholak OpenFOAM 9 November 22, 2011 11:02 tilek CFX 3 May 8, 2011 08:39 ParodDav CFX 5 April 29, 2007 19:13 Ning FLUENT 0 March 18, 2007 13:51