The apparent thermal radiation properties of an isothermal V-groove with specularly reflecting walls

Abstract

Rece ntl y the re has been a great deal 0(' work reo ported in the literature on the problem of predicting the appare nt thermal radiation properti es of cavities and rough surfaces when the properties of ideally smooth surfaces of the same material are known. An interesting problem that has not been previously treated very completely is reRection by an iso thermal V -groove, whose walls are specularly reRecting. Sparrow and Lin [3]1 have reported some results for the effec tive absorptance of suc h a groove. Their method of analysis is followed here using a simpler procedure, extended somewh at, and results are given for effec tive directional re Rectance. The main limitation on the results reported here is due to the assumption tha t the V -groove has spec ular walls. This assumption is valid when the wavelength of the incident radiation is much less than the characteristic dime nsions of the groove, and at the same time much greater than the characteristic dimensions of the roughness of the groove walls. Experimental results re ported by the author [4] have shown this to be true.