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## what is under relaxation factor?

Posted August 27, 2012 at 09:23 by kira

something to keep in mind:
Quote:
Originally Posted by Phil
;140717
Each of the variables(mass,mom,density) represents an equation the solver is trying to solve. Each iteration the values obtained for the variables should get closer and closer together - converge. FOR SIMPLE PROBLEMS ESPECIALLY COLD FLOWS WITHOUT COMBUSTION YOU SHOULD SIMPLY KEEP THE RELAXATION FACTORS AT DEFAULT.

Sometimes for many many reasons the solution can become unstable so a relaxation factor is used - takes part of value from previous iteration
...
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Posted August 10, 2012 at 13:50 by lakeat (Daniel Wei's CFD Blog: (http://lakeat.co.nf/))

http://www.cfd-online.com/Forums/ope...residuals.html
Senior Member
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## 2D unstructured mesher in F90

Posted August 9, 2012 at 08:23 by truffaldino
Tags

This is 2D unstructured mesher.

tri_mesh.f90 is a mesher and the rest are input files

Example 1: Cavity flow driven by upper cavity wall

file: cavity_bc.txt

Example 2: flow past NACA 0012 airfoil

files: NACA0012_bc.txt - airfoil
wt_bc.txt - wind tunnel
wake_bc.txt -wake

Description of the program is placed in the header of tri_mesh.f90
Attached Files
 tri_mesh.f (100.5 KB, 257 views) cavity_bc.txt (65 Bytes, 140 views) NACA0012_bc.txt (16.6 KB, 164 views) wt_bc.txt (184 Bytes, 135 views) wake_bc.txt (5.5 KB, 247 views)
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## Methods for creating cellZones and faceZones

Posted July 26, 2012 at 11:03 by kalyangoparaju

Friends,

I've been playing around a lot with the creation of cellZones and faceZones and here is what I have to report !

Till now I have found 3 ways to do it. ( I am sure there are more)

1. To use setSet utility and cellZonesSet and faceZoneSet commands.
This works amazingly well and creates the zones. A small problem can arrise if you are trying to set zones for an internal flow case and at the center of your geometry you have level 0 cells....
Attached Thumbnails

Attached Files
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## Torture

Posted July 26, 2012 at 05:11 by sumit_raised

Mentally tortured after two nights thinking on the applications of Computational Fluid Dynamics, Computation, Programming and my contribution to the field.

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