Accession Number:

ADA014826

Title:

Research Effort in Atmospheric Propagation.

Descriptive Note:

Final technical rept. 1 Dec 74-30 May 75,

Corporate Author:

OHIO STATE UNIV RESEARCH FOUNDATION COLUMBUS

Report Date:

1975-08-01

Pagination or Media Count:

51.0

Abstract:

This report presents work performed on 1 The propagation of light through aircraft boundary layers 2 The measurement and interpretation of refractive index spectra at high altitudes and 3 The temporal spectra of angle-of-arrival fluctuations. A method of analyzing the data from the experiment on light beams propagating through aircraft boundary layers to obtain the boundary layer MTF was presented. Next a calculation of the effects of velocity and air mean free path on wire microthermal measurements was reported. The results were that the procedure of calibrating a microthermal sensor at zero velocity and making measurements at low altitude at Mach 1 can have up to 17 error. Further, flying at an altitude of 20 km where the air molecular mean free path is larger can increase the error another 4. A discussion of refractive index spectra obtained from airborne microthermal measurements resulted in an empirical formula which could be made to fit the data. The formula involved the addition of two von Karman type of spatial spectra. The data showed outer scales between 300 to 1000 meters. Finally, results of an analysis on the temporal spectrum of angle-of-arrival fluctuations were presented. The model included a moving source, and a position proportional detector. The resulting curve showed a peak contribution from refractive index fluctuations of size equal to one fifth the source height.

Subject Categories:

  • Atmospheric Physics
  • Optics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE