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Problems with geometry quality

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Hello. First of all i am fairly new comsol user. Currently i am studying heating of fused silica fibers (https://en.wikipedia.org/wiki/Optical_fiber) for purposes of laser applications. Typical optical fiber is very thin cylinder (diameter is 125 um) with big length (1 m and much more). So this is the place where the problem appears. I draw a fiber with lenght of 1.5 mm and diameter of 125 um and comsol manage it very good (see two files "Length_1500um_General View.jpg" and "Length_1500um_Transverse View.jpg"). But fiber with length of 1 m looks very low poly and modeling heating in such geometry is worthless ("Length_1m_General View.jpg" and "Length_1m_Transverse View.jpg"). Is there any mean to make comsol maintain quality in this situation?



4 Replies Last Post Sep 1, 2019, 5:20 a.m. EDT
Jeff Hiller COMSOL Employee

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Posted: 5 years ago Aug 28, 2019, 5:17 p.m. EDT

This is a rendering effect due to the high aspect ratio, and it has been discussed before in this Discussion Forum, see e.g. https://www.comsol.com/forum/thread/77211/object-shape-changing-due-to-high-aspect-ratio?last=2015-05-19T18:02:19Z .

The cross section of your geometric object is still a circle even if it does not look that way on screen. This will become obvious when you mesh one of the end surfaces of your fiber.

Best regards,

Jeff

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Jeff Hiller
This is a rendering effect due to the high aspect ratio, and it has been discussed before in this Discussion Forum, see e.g. https://www.comsol.com/forum/thread/77211/object-shape-changing-due-to-high-aspect-ratio?last=2015-05-19T18:02:19Z . The cross section of your geometric object is still a circle even if it does not look that way on screen. This will become obvious when you mesh one of the end surfaces of your fiber. Best regards, Jeff

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Posted: 5 years ago Aug 29, 2019, 2:53 p.m. EDT

This is a rendering effect due to the high aspect ratio, and it has been discussed before in this Discussion Forum, see e.g. https://www.comsol.com/forum/thread/77211/object-shape-changing-due-to-high-aspect-ratio?last=2015-05-19T18:02:19Z .

The cross section of your geometric object is still a circle even if it does not look that way on screen. This will become obvious when you mesh one of the end surfaces of your fiber.

Best regards,

Jeff

Thank you. I will look through your link.

>This is a rendering effect due to the high aspect ratio, and it has been discussed before in this Discussion Forum, see e.g. https://www.comsol.com/forum/thread/77211/object-shape-changing-due-to-high-aspect-ratio?last=2015-05-19T18:02:19Z . > >The cross section of your geometric object is still a circle even if it does not look that way on screen. This will become obvious when you mesh one of the end surfaces of your fiber. > >Best regards, > >Jeff Thank you. I will look through your link.

Jeff Hiller COMSOL Employee

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Posted: 5 years ago Aug 29, 2019, 4:11 p.m. EDT
Updated: 5 years ago Aug 29, 2019, 4:11 p.m. EDT

Here is a better link on the same topic: https://www.comsol.com/forum/thread/36108/geometry-of-a-cylinder?last=2013-07-04T06:45:03Z

Jeff

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Jeff Hiller
Here is a better link on the same topic: https://www.comsol.com/forum/thread/36108/geometry-of-a-cylinder?last=2013-07-04T06:45:03Z Jeff

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Posted: 5 years ago Sep 1, 2019, 5:20 a.m. EDT

In topic (https://www.comsol.com/forum/thread/77211/object-shape-changing-due-to-high-aspect-ratio?last=2015-05-19T18:02:19Z ) Daniel Connelly suggest to use scaling rules to extend solution to longer lengths but i do not know how to do it. How to apply these rules in comsol?

In topic (https://www.comsol.com/forum/thread/77211/object-shape-changing-due-to-high-aspect-ratio?last=2015-05-19T18:02:19Z ) Daniel Connelly suggest to use scaling rules to extend solution to longer lengths but i do not know how to do it. How to apply these rules in comsol?

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