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Radiosity (heat Transfer)
In radiometry, radiosity is the radiant flux leaving (emitted, reflected and transmitted by) a surface per unit area, and spectral radiosity is the radiosity of a surface per unit frequency or wavelength, depending on whether the spectrum is taken as a function of frequency or of wavelength. The SI unit of radiosity is the watt per square metre (), while that of spectral radiosity in frequency is the watt per square metre per hertz (W·m−2·Hz−1) and that of spectral radiosity in wavelength is the watt per square metre per metre (W·m−3)—commonly the watt per square metre per nanometre (). The CGS unit erg per square centimeter per second () is often used in astronomy. Radiosity is often called in branches of physics other than radiometry, but in radiometry this usage leads to confusion with radiant intensity. Mathematical definitions Radiosity Radiosity of a ''surface'', denoted ''J''e ("e" for "energetic", to avoid confusion with photometric quantities), is defined as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
View Factor
In radiative heat transfer, a view factor, F_, is the proportion of the radiation which leaves surface A that strikes surface B. In a complex 'scene' there can be any number of different objects, which can be divided in turn into even more surfaces and surface segments. View factors are also sometimes known as configuration factors, form factors, angle factors or shape factors. Summation of view factors Because radiation leaving a surface is conserved, the sum of all view factors ''from'' a given surface, S_i, is unity: :\sum_^n = 1 For example, consider a case where two blobs with surfaces ''A'' and ''B'' are floating around in a cavity with surface ''C''. All of the radiation that leaves ''A'' must either hit ''B'' or ''C'', or if ''A'' is concave, it could hit ''A''. 100% of the radiation leaving ''A'' is divided up among ''A'', ''B'', and ''C''. Confusion often arises when considering the radiation that ''arrives'' at a ''target'' surface. In that case, it generally does n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
