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Old   January 28, 2008, 02:37
Default Radiation
  #1
Babila Ramamoorthy
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Hi,

I am M.S (Mech) student, I am lookig for some help in the computation of absorption coefficient from the spectroscopic database (HITRAN), I greatly appreciate any suggestions or reference in this area,

Thanks Babila
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Old   January 28, 2008, 10:19
Default Re: Radiation
  #2
opaque
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Dear Babila,

Have you read the book Radiative Heat Transfer, by Dr. Michael Modest. He clearly explains how to obtain "reduced" absorption coefficients from detailed spectral data. In addition, the book includes source code examples that can be used with the HITRAN database.

Opaque..

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Old   January 28, 2008, 14:06
Default Re: Radiation
  #3
Ertan Karaismail CFD&AMP
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Are you going to develop line-by-line solution ????! Why not using models? As far as I know HITRAN gives absorption cross-sections, not the absorption coefficients.
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Old   January 28, 2008, 20:07
Default Re: Radiation
  #4
Babila Ramamoorthy
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Hi,

Thank you for the responses. I am very new in this field, so your replies are very helpful.

What I am interested is the implementation of FSCK model (Modest). But the first step in implementing this model is obtaining raw absorption coefficient value from the line by line spectrum at certain spectral locations. I can understand how to calculate the absorption coefficient at a certain wavenumber due to a single line (either using Lorentz or voigt profile). But to obtain the absorption coefficient at a certain wave number do i have to sum up the contribution due to all the lines in the database?

I have Modest book (93 edition), this does not have any source code that can be directly used with HITRAN database. Probably the new edition has it, I think,

Thanks again, I greatly appreciate your help
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Old   January 29, 2008, 01:38
Default Re: Radiation
  #5
Ertan Karaismail CFD&AMP
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You'd better get the newest edition of Modest's book in which FSCK method is explained in more detail. Besides, the best sources for modeling of radiative properties are dissertations. Keep this in mind. You can look for dissertations on this subject. You may take a look at the dissertation of Hongmei Zang. If you can't find it from UMI let me know, I can send it to you. That might be worth to go through.

Generally the contributions from each lines are additive, but since I don't know the details of FSCK I am not very sure for your case. Besides, contributions of each line may be associated with weighting factors.

Good luck

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Old   January 30, 2008, 03:26
Default Re: Radiation
  #6
Babila Ramamoorthy
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Hi,

Thank you for the suggestion. I do not have access to UMI, so if you can send me, it would be really helpful. I would be getting the Modest new edition in a week, hopefully it should help me.

I have also a paper by Modest on FSCK which also suggest that to get the absorption coefficient at a given wave number, I have to sum the contributions from lines, but I am not sure whether it means all the lines in the database, since the database is huge (60000+ lines for CO2), such a calculation would be really enormous. I was wondering if I have misunderstood the idea or is that what I should do. I hope that I can get better idea with the new edition of the book.
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