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-   -   Graphics Problems (http://www.cfd-online.com/Forums/fluent/28202-graphics-problems.html)

Amadou Sowe February 8, 2001 15:26

Graphics Problems
 
I have a Dell Precision 620 workstation preloaded with Windows 2000. In fluent 5.5.14 I read in a mesh file of a pipe of radius 0.1 in. and 1.0 in length. After reading the mesh file and running the grid check utility, I issue the grid display command. The pipe is displayed with no errors. The same display command now leads to a floating point error after scaling the domain by 1.0e-5 in all coordinate directions. This error disables all display capabilities in my current fluent session. The actual project I am working on has a more complex geometry than the pipe I have described above but the error that results is the same. For the sake of easy repeatability I therefore suggest we restrict our efforts on the pipe problem.

I replaced my factory-installed Elsa Gloria 2 pro graphics adapter with an Intense 3D Wildcat Pro thinking that this will resolve my problems. It did not. I have installed updated graphics drivers, BIOS patches, Windows 2000 patches but still no resolution to my problem.

My guess is that this problem will be resolved by Installing Windows NT instead Windows 2000. So I would like all Dell Precision 620 (may be 420) owners to help me by running the same pipe problem on their machines. Whether you have Win NT or Win 2000 your help will still be valuable. For others who do not have the PCs I am talking about, your inputs are still welcome. Thanks in advance for your help.

John C. Chien February 11, 2001 13:48

Re: Graphics Problems
 
(1). If the radius is 0.1, then smallest mesh could be 0.001. And if you scale it by 0.00001, the mesh becomes 0.00000001. (2). If the mesh location difference between two points is 0.0002, then it will become 0.000000002 after scaling. (3). Can the code handle this?

Amadou Sowe February 12, 2001 13:53

Re: Graphics Problems
 
The code should be able to handle this since it has a double precision option. This means that the mantissa to my real number representation has been extended. I just calculated my PC machine unit, it is about 1e-16. The machine unit is the smallest possible increment in a stored mantissa. If a number is represented as X = M.10^i where M = .d1d2d3...dk, i is an integer normally called the characteristic or exponent, and d1 is not zero, then M is called the mantissa.

Kai Kang February 12, 2001 14:01

Re: Graphics Problems
 
I am using dell620 and optiplex PC with NT4.0/service pack 4. I remember quite long ago, somebody asked a similar question, you might want to check previous archives.

I had this only once, what I did was save it after scaling and reread in. If you'd like, I could check it out on my wkstation...


Amadou Sowe February 12, 2001 14:15

Re: Graphics Problems
 
After scaling, I saved it and reread it but received the same graphics disabling error right after clicking on the display -> grid command.

I could check previous archives if I knew what to look for. Any ideas.

Finally, I will be more than glad if you can check it out on your Dell 620 workstation. What graphics adapter do you have in your workstation 620?


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