Atmospheric Radiation

sylangear · November 30, 2018, 12:39

Hello everyone,

I did a quick search on the forum for "Terrestrial Solar Irradiation" but couldn't find a solution to my problem.

I'm trying to see the effect of the solar radiation emitted and reflected by the earth's surface. I used the discrete transfer and already selected the solar radiation from general settings. However, it just calculates the solar radiation that directly reached to body. I want to add also terrestrial solar radiation(or atmospheric radiation) to my model by using open sky and constant earth surface temperature. Is there any way to calculate it?

I'm using Floefd 16 with Creo. If I'm missing anything about physics, please also tell me. Any help would be appreciated. Thank you!

DB99 · January 7, 2019, 23:59

Don't think it is available but see if you can set your Air property to have absorption and semi-transparent. This air absorption aspect of this is "participating media" as opposed to semi-transparent solid. Might need Combustion Module of EFD to do this. Best to ask EFD product manager for feature set per software module.
For terrestrial reflection search for "albedo" which is generally in non-spectral model considered in bulk to be 0.3 or so of incoming.

Boris_M · January 8, 2019, 04:33

Hi Volkan,

This shouldn't be a problem but you need to know the emissivity of the earth's surface probably more like an average as a field of grass is different than a rock of course.
The discrete transfer radiation model (DTRM) can handle reflection in a diffusive way and should be perfectly fine with that.

The atmospheric radiation you should be perfectly fine to assume the environment temperature as that is your atmosphere. You don't need to use absorption of gasses as this is considered as the environment temperature. that radiates back onto the body.
Any open sky is basically blocked by a lot of air and in a cold winter night with a clear sky the temperatures get colder, hence the environment temperature is lower and that is it.

If you need a specific effect, then you would need to explain in more detail what you are trying to model because the mentioned method works perfectly in 99% of all cases.

Regards,
Boris

DB99 · January 16, 2019, 12:47

Please see the attached Terrestrial Radiation Spectrum along with digitized data for use in FloEFD.

November 30, 2018, 12:39	Atmospheric Radiation	#1
sylangear New Member Volkan Join Date: Nov 2018 Posts: 1 Rep Power: 0	Hello everyone, I did a quick search on the forum for "Terrestrial Solar Irradiation" but couldn't find a solution to my problem. I'm trying to see the effect of the solar radiation emitted and reflected by the earth's surface. I used the discrete transfer and already selected the solar radiation from general settings. However, it just calculates the solar radiation that directly reached to body. I want to add also terrestrial solar radiation(or atmospheric radiation) to my model by using open sky and constant earth surface temperature. Is there any way to calculate it? I'm using Floefd 16 with Creo. If I'm missing anything about physics, please also tell me. Any help would be appreciated. Thank you!

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January 7, 2019, 23:59		#2
DB99 New Member DB Join Date: Jan 2019 Posts: 28 Rep Power: 7	Don't think it is available but see if you can set your Air property to have absorption and semi-transparent. This air absorption aspect of this is "participating media" as opposed to semi-transparent solid. Might need Combustion Module of EFD to do this. Best to ask EFD product manager for feature set per software module. For terrestrial reflection search for "albedo" which is generally in non-spectral model considered in bulk to be 0.3 or so of incoming.

January 8, 2019, 04:33		#3
Boris_M Disabled Join Date: Jul 2009 Posts: 616 Rep Power: 24	Hi Volkan, This shouldn't be a problem but you need to know the emissivity of the earth's surface probably more like an average as a field of grass is different than a rock of course. The discrete transfer radiation model (DTRM) can handle reflection in a diffusive way and should be perfectly fine with that. The atmospheric radiation you should be perfectly fine to assume the environment temperature as that is your atmosphere. You don't need to use absorption of gasses as this is considered as the environment temperature. that radiates back onto the body. Any open sky is basically blocked by a lot of air and in a cold winter night with a clear sky the temperatures get colder, hence the environment temperature is lower and that is it. If you need a specific effect, then you would need to explain in more detail what you are trying to model because the mentioned method works perfectly in 99% of all cases. Regards, Boris