# Repeated Indicies

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

 August 21, 2005, 17:30 Repeated Indicies #1 Dan Guest   Posts: n/a i know that the convention for repeated indicies is summation. but if i have (where bracketed terms are the indicies) - Ans1 = [ M(ij) * M(ij) ] / [ F(kl) * F(kl) ] is this the same as - Ans2 = [ M(ij) * M(ij) ] / [ F(ij) * F(ij) ] is Ans1 = Ans2 ???

 August 21, 2005, 18:19 Re: Repeated Indicies #2 Ahmed Guest   Posts: n/a ans2 is just rubbish. The rule is very simple, no index can be repeated more than twice in the same term

 August 22, 2005, 05:45 Re: Repeated Indicies #3 Dan Guest   Posts: n/a hi ahmed, thanks for your reply. i have regularly seen the following expression for the dynamic smagorinsky coefficient ... C = -0.5 * [L(ij)M(ij)] / [M(ij)M(ij)] are you saying that this is incorrect?

 August 23, 2005, 00:44 Re: Repeated Indicies #4 Ahmed Guest   Posts: n/a Yes(in what refers to the indices). Once again the rule "No index may appear more than twice in any term" and the expression as written by you breaks the rule. Remember all these are dummy indices and meant to indicate summation so any letter can do but for clarity they are not repeated more than twice, books on turbulence in general have an appendix that list all these rules so stretch your legs to the library or pay ten dollars to amazon and they will send you the book by Aris.

 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 hamzamotiwala STAR-CCM+ 12 December 9, 2011 05:35 mullenc525 CFX 2 December 21, 2010 14:57 Mlynam STAR-CCM+ 3 July 6, 2010 12:24 tryingof OpenFOAM Bugs 17 December 7, 2008 05:41 santos OpenFOAM Running, Solving & CFD 19 January 17, 2008 10:07

All times are GMT -4. The time now is 02:12.