Information on multiband radiation

me3840 · June 23, 2020, 10:19

Hello all,

I'm trying to incorporate (solar) radiation into one of my models and I'm a bit confused on the multiband setup.

Clearly in the viewFactorCoeffs subdict I can put in nBands 2. But where do I choose the frequency cutoffs for those bands?

Further in the solarLoadCoeffs model I see the tutorials have written:
spectralDistribution (2 1)

What exactly is this referring to? I can't find any notes about it in the source code, just that somehow it's describing the energy spectrum.

Anyone with any clues?

Thanks!

Fetze · March 4, 2021, 05:09

do you solved the problem?

lumpor · March 25, 2021, 10:33

I think it's simply the proportion between the different frequencies you have. If the distribution is (2 1) it means 2 thirds of the radiation is of the first frequency and one third of the radiation is of the second frequency.

Then in boundaryRadiationProperties you can specify the emissivity and aborptivity of the boundaries. For example emissivity ( 0.5 0.8) absorptivity ( 0.5 0.8 ) means that the patch absorbs and emits 50% of the energy from the first frequency band and 80% of the second one.

I don't think the actual frequency in Hz matters to the solver. You just make a mental note of which frequency each column represents.

June 23, 2020, 10:19	Information on multiband radiation	#1
me3840 Senior Member Join Date: Nov 2010 Location: USA Posts: 1,232 Rep Power: 24	Hello all, I'm trying to incorporate (solar) radiation into one of my models and I'm a bit confused on the multiband setup. Clearly in the viewFactorCoeffs subdict I can put in nBands 2. But where do I choose the frequency cutoffs for those bands? Further in the solarLoadCoeffs model I see the tutorials have written: spectralDistribution (2 1) What exactly is this referring to? I can't find any notes about it in the source code, just that somehow it's describing the energy spectrum. Anyone with any clues? Thanks!

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March 4, 2021, 05:09		#2
Fetze New Member Tobias Join Date: Apr 2019 Posts: 4 Rep Power: 7	do you solved the problem?

March 25, 2021, 10:33		#3
lumpor Member Fabian Friberg Join Date: Dec 2020 Posts: 31 Rep Power: 5	I think it's simply the proportion between the different frequencies you have. If the distribution is (2 1) it means 2 thirds of the radiation is of the first frequency and one third of the radiation is of the second frequency. Then in boundaryRadiationProperties you can specify the emissivity and aborptivity of the boundaries. For example emissivity ( 0.5 0.8) absorptivity ( 0.5 0.8 ) means that the patch absorbs and emits 50% of the energy from the first frequency band and 80% of the second one. I don't think the actual frequency in Hz matters to the solver. You just make a mental note of which frequency each column represents.