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-   -   What happens by doing Bandwidth Reduction? (http://www.cfd-online.com/Forums/fluent/72240-what-happens-doing-bandwidth-reduction.html)

mariachi January 29, 2010 12:50

What happens by doing Bandwidth Reduction?
 
Hey friends,

In fluent, what happens when u do bandwidth reduction by grid>reorder>domain

Why and when do u do it?

Thanks

DoHander January 30, 2010 13:52

After you read your mesh in Fluent you can do the bandwidth reduction. Basically Fluent will renumber the nodes of your mesh in order to have a "more diagonal" array. This will allow you to use less memory and also the solution will converge faster.

Do

mariachi January 31, 2010 06:25

Hey DoHander,

So basically, it means that one should make it a practice to always do bandwidth reduction after reading any mesh into Fluent...

DoHander January 31, 2010 13:54

If you use any of the implicit solvers of Fluent yes, you should always do the bandwidth reduction. For the explicit solver this is useless.

Do

mariachi February 1, 2010 12:26

Thanks DoHander :)

daandb February 28, 2013 06:24

I also have a question on this, till what value you need to reorder to achieve the most optimal bandwidth? Seem to me that the lower the bandwidth value the better?

cfd seeker April 15, 2014 02:32

Quote:

Originally Posted by daandb (Post 410606)
I also have a question on this, till what value you need to reorder to achieve the most optimal bandwidth? Seem to me that the lower the bandwidth value the better?

Yup, lower the bandwidth value the better the solution will get in terms of solution time!! But you cannot control the value to which the bandwidth (of matrix) can be reduced, as it depends on the number of non-zero entries in the matrix(the matrix generated as the fluent solves the N-S equations)

Far July 19, 2014 05:59

details can be found here...

http://en.wikipedia.org/wiki/Banded_matrix

This also clearly shows why you cannot have advantage of reordering for explicit solver...

Far July 19, 2014 06:05

details can be found here...

http://en.wikipedia.org/wiki/Banded_matrix

This also clearly shows why you cannot have advantage of reordering for explicit solver...


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