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

Blog Entries

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

Old

what is under relaxation factor?

Posted August 27, 2012 at 10:23 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
...
New Member
Posted in Uncategorized
Views 492 Comments 1 kira is offline Edit Tags
Old

Useful Threads

Posted August 10, 2012 at 14:50 by lakeat (Daniel Wei's CFD Blog: (http://lakeat.co.nf/))

http://www.cfd-online.com/Forums/ope...residuals.html
lakeat's Avatar
Senior Member
Posted in Uncategorized
Views 675 Comments 0 lakeat is offline Edit Tags
Old

2D unstructured mesher in F90

Posted August 9, 2012 at 09:23 by truffaldino

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
File Type: f tri_mesh.f (100.5 KB, 186 views)
File Type: txt cavity_bc.txt (65 Bytes, 109 views)
File Type: txt NACA0012_bc.txt (16.6 KB, 130 views)
File Type: txt wt_bc.txt (184 Bytes, 106 views)
File Type: txt wake_bc.txt (5.5 KB, 218 views)
truffaldino's Avatar
Senior Member
Posted in Uncategorized
Views 731 Comments 3 truffaldino is offline Edit Tags
Old

Methods for creating cellZones and faceZones

Posted July 26, 2012 at 12:03 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
Click image for larger version

Name:	setSet_substrate.PNG
Views:	162
Size:	72.9 KB
ID:	80   Click image for larger version

Name:	constant_zones.PNG
Views:	158
Size:	95.0 KB
ID:	81   Click image for larger version

Name:	constant_substrate.PNG
Views:	145
Size:	84.3 KB
ID:	82   Click image for larger version

Name:	snappy_zones.PNG
Views:	156
Size:	95.2 KB
ID:	83   Click image for larger version

Name:	snappy_substrate.PNG
Views:	150
Size:	79.9 KB
ID:	84  

Attached Files
Member
Posted in Uncategorized
Views 573 Comments 0 kalyangoparaju is offline Edit Tags
Old

Torture

Posted July 26, 2012 at 06:11 by sumit_raised



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

sumit_raised's Avatar
New Member
Posted in Uncategorized
Views 452 Comments 0 sumit_raised is offline Edit Tags

All times are GMT -4. The time now is 17:38.