Accession Number:

AD0607537

Title:

THEORETICAL AND EXPERIMENTAL EVALUATION OF AN ENCLOSURE FOR THE INVESTIGATION OF ATMOSPHERIC LONGWAVE RADIATION PHENOMENA.

Descriptive Note:

Final rept.,

Corporate Author:

TEXAS UNIV AUSTIN ELECTRICAL ENGINEERING RESEARCH LAB

Personal Author(s):

• Willis,Glen E.
• Duchon,Claude E.

Report Date:

1964-06-30

Pagination or Media Count:

72.0

Abstract:

An enclosure was constructed of a polyethylene film top and four polished aluminum walls resting on a platform on the ground. Measurements of longwave radiation and air temperature were made at various locations inside the enclosure as a function of time under clear nighttime skies. A mathematical model was formulated in which the upward and downward components of radiation were computed from radiative transfer theory as a function of height at the center of the enclosure. The computations show that with a wall reflectivity of 0.95, a polyethylene film reflectivity of 0.15, and the lower boundary radiating as a black body, the divergence of net radiation due only to the walls is the same order of magnitude as the divergence measured in the atmosphere. Values of divergence were measured inside the real enclosure of the same order of magnitude as predicted by the theory. Consequently, the concept of a horizontally homogeneous radiating atmosphere, attained if the walls acted as specular reflectors with a reflectivity of unity, could not be realized. Author

Descriptors:

• TEST FACILITIES
• INFRARED RADIATION
• MATHEMATICAL MODELS
• CONSTRUCTION
• POLYETHYLENE PLASTICS
• FILMS
• ALUMINUM
• REFLECTION
• BLACKBODY RADIATION
• THERMODYNAMICS

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE