Accession Number : ADA311625

Title :   Inverse Scattering Methods for Reconstructing Fluids.

Descriptive Note : Transmittal document,

Corporate Author : WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB

Personal Author(s) : Rouseff, Daniel ; Winters, Kraig B.

PDF Url : ADA311625

Report Date : JUL 1996

Pagination or Media Count : 12

Abstract : The reconstruction of a two dimensional moving fluid from acoustic transmission measurements is considered. The fluid is described by both a scalar index of refraction and a vector velocity. If the measured data are assumed to be straight ray geometric projections of the flow, it is known that inversion for the vector velocity is an underdetermined problem. In the present work, it is shown that if the measured data are assumed to satisfy a linearized time harmonic wave equation, then a unique inversion for the vector velocity is possible. This result is a distinctly finite wavelength effect indicating why ray based methods fail to produce a complete reconstruction. A filtered backpropagation algorithm for the tomographic reconstruction of the vector flow field is derived.

Descriptors :   *FLOW VISUALIZATION, *TOMOGRAPHY, REPRINTS, TWO DIMENSIONAL, REFRACTIVE INDEX, FLOW FIELDS, SOUND TRANSMISSION, ACOUSTIC MEASUREMENT, VECTOR ANALYSIS, SCALAR FUNCTIONS, INVERSE SCATTERING, RAY TRACING, ACOUSTIC VELOCITY, DIFFRACTION ANALYSIS.

Subject Categories : Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE