Ivar KJELBERG
COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted:
1 decade ago
Feb 27, 2013, 1:58 a.m. EST
Hi
do you have some "air / vacuum around your wave-guide?
I do remember from previous simulations that the PML worked better when they surrounded a all air domain
--
Good luck
Ivar
Hi
do you have some "air / vacuum around your wave-guide?
I do remember from previous simulations that the PML worked better when they surrounded a all air domain
--
Good luck
Ivar
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Posted:
1 decade ago
Feb 28, 2013, 1:48 p.m. EST
3 things are important:
1. enough mesh elements in the PML
2. same material for PML and the domain it touches
3. change PML type to General if you want to change PML scaling factor and other parameters manually
3 things are important:
1. enough mesh elements in the PML
2. same material for PML and the domain it touches
3. change PML type to General if you want to change PML scaling factor and other parameters manually
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Posted:
1 decade ago
Mar 1, 2013, 10:53 a.m. EST
Hi,
Thank you for the suggestions.
I haven’t used any air/ vacuum my system is a waveguide Silicone (n=3.4) as core between silica (n=1.45) and water (n=1.33) as claddings.
I split the PML in to 3 for each material in my system so that the PML and the materials match.
I have used a sweep mesh for the PML from the interface of the Materials and the PML with 10 elements. But I am still getting some back reflections?
When you said change the PML to general for manual scaling is it in version 4.3 ? I didn’t see an option to do that in the definition node.
Best regards,
Hi,
Thank you for the suggestions.
I haven’t used any air/ vacuum my system is a waveguide Silicone (n=3.4) as core between silica (n=1.45) and water (n=1.33) as claddings.
I split the PML in to 3 for each material in my system so that the PML and the materials match.
I have used a sweep mesh for the PML from the interface of the Materials and the PML with 10 elements. But I am still getting some back reflections?
When you said change the PML to general for manual scaling is it in version 4.3 ? I didn’t see an option to do that in the definition node.
Best regards,
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Posted:
1 decade ago
Mar 1, 2013, 3:05 p.m. EST
When you said change the PML to general for manual scaling is it in version 4.3 ? I didn’t see an option to do that in the definition node.
It's in the settings for PML. Geometric Settings, Type: General
[QUOTE]
When you said change the PML to general for manual scaling is it in version 4.3 ? I didn’t see an option to do that in the definition node.
[/QUOTE]
It's in the settings for PML. Geometric Settings, Type: General
Ivar KJELBERG
COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
Please login with a confirmed email address before reporting spam
Posted:
1 decade ago
Mar 2, 2013, 3:11 a.m. EST
Hi
then I have a question, if we have different materials, and we split up the PML accordingly to have the "same material" what about oblique vaves hitting the interface in the PML region, would that scatter ?
What is best, set all air around and PML air, or remove the air for large INF domains, and split the PML and give material properties ?
--
Have fun COMSOLing
Ivar
Hi
then I have a question, if we have different materials, and we split up the PML accordingly to have the "same material" what about oblique vaves hitting the interface in the PML region, would that scatter ?
What is best, set all air around and PML air, or remove the air for large INF domains, and split the PML and give material properties ?
--
Have fun COMSOLing
Ivar
Please login with a confirmed email address before reporting spam
Posted:
1 decade ago
Mar 4, 2013, 10:39 a.m. EST
Hi,
then I have a qusion, if we have different mateials, and we split up the PML accordingly to have the "same material" what about oblique vaves hitting the interface in the PML region, would that scatter ?
I haven't seen the back-scattering at such interfaces. Sometimes there is a "surface wave" going along this interface. But seems like scattering BC outside of PML takes care of it.
What is best, set all air around and PML air, or remove the air for large INF domains, and split the PML and give material properties ?
I never set up air all around.For the simulations I do, it won't represent the correct structure. But I guess it should work in antenna-type simulations just fine.
Hi,
[QUOTE]
then I have a qusion, if we have different mateials, and we split up the PML accordingly to have the "same material" what about oblique vaves hitting the interface in the PML region, would that scatter ?
[/QUOTE]
I haven't seen the back-scattering at such interfaces. Sometimes there is a "surface wave" going along this interface. But seems like scattering BC outside of PML takes care of it.
[QUOTE]
What is best, set all air around and PML air, or remove the air for large INF domains, and split the PML and give material properties ?
[/QUOTE]
I never set up air all around.For the simulations I do, it won't represent the correct structure. But I guess it should work in antenna-type simulations just fine.
Ivar KJELBERG
COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
Please login with a confirmed email address before reporting spam
Posted:
1 decade ago
Mar 4, 2013, 2:38 p.m. EST
Hi
Thanks for your comments ;)
--
Good luck
Ivar
Hi
Thanks for your comments ;)
--
Good luck
Ivar
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Posted:
1 decade ago
Mar 11, 2013, 7:30 a.m. EDT
Dear All
thanks allot for these information, i also simulate the silicon wave guide: brillouin scattering ( interaction between the pump and Stoke waves), i used the PML to prevent the reflection in the wave guide, but still i can not get the scattered wave because i do not know how to simulate the Stoke wave and get the acoustic mode. I used the RF electromagnetic and elastic wave modules.
please any suggestions and if you want i will attach my Comsol file.
Best Regards
Dear All
thanks allot for these information, i also simulate the silicon wave guide: brillouin scattering ( interaction between the pump and Stoke waves), i used the PML to prevent the reflection in the wave guide, but still i can not get the scattered wave because i do not know how to simulate the Stoke wave and get the acoustic mode. I used the RF electromagnetic and elastic wave modules.
please any suggestions and if you want i will attach my Comsol file.
Best Regards