Accession Number : ADA133258

Title :   Application of Two-Dimensional Discrete-Ordinates Methods to Multiple Scattering of Laser Radiation.

Descriptive Note : Rept. for 6 Dec 82-17 Feb 83,

Corporate Author : ARMY ARMAMENT RESEARCH AND DEVELOPMENT COMMAND ABERDEEN PROVING GROUND MD CHEMICAL SYSTEMS LAB

Personal Author(s) : Zardecki,A ; Gerstl,S A W ; Embury,J F

PDF Url : ADA133258

Report Date : Jun 1983

Pagination or Media Count : 30

Abstract : The discrete-ordinates finite element radiation transport code TWOTRAN is applied to describe the multiple scattering of a laser beam from a reflecting target. For a model scenario involving a 99% relative humidity rural aerosol, the authors compute the average intensity of the scattered radiation and correction factors to the Lambert-Beer law arising from multiple scattering. As their results indicate, two-dimensional x-y and r-z geometry modeling can reliably describe a realistic three-dimensional scenario. Specific results are presented for the two visual ranges of 1.52 and 0.76 km which show that for sufficiently high aerosol concentrations (e.g., equivalent to V=0.76 km) the target signature in a distant detector becomes dominated by multiply scattered radiation from interactions of the laser light with the aerosol environment. The merits of the scaling group and the delta M approximation for the transfer equation are also explored.

Descriptors :   *Numerical methods and procedures, *Computations, *Fortran, *Radiative transfer, Target signatures, Algorithms, Laser beams, Two dimensional, Coding, Finite element analysis, Scenarios, Aerosols, Scattering, Equations, Grids(Coordinates)

Subject Categories : Theoretical Mathematics
      Computer Programming and Software
      Thermodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE