Accession Number : ADA190909

Title :   Computer Tomography and Hybrid Optical/Digital Methods for Aerodynamic Measurements.

Descriptive Note : Final rept. 1 Jan 84-28 Dec 87,

Corporate Author : MICHIGAN UNIV ANN ARBOR DEPT OF MECHANICAL ENGINEERING AND APPLIED MECHANICS

Personal Author(s) : Vest, C M

PDF Url : ADA190909

Report Date : 28 Dec 1987

Pagination or Media Count : 44

Abstract : A hybrid optical/digital system has been developed to measure instantaneous, three-dimensional, density distributions in aerodynamic flows. The system uses a pulsed laser and discrete phase-step holographic interferometry, resulting in excellent phase resolution and a substantial level of automation of phase readout. The system uses reflection-, as well as transmission-, holography. Data are analyzed by computer tomography using a new algorithm (constrained iterative convolution) developed during this program. The entire system was used to study turbulent helium jets, disclosing their basic structures. Research also was conducted to develop methods for computer tomographic analysis when the optical probing rays are bent due to strong refraction, e.g., around shocks. Two iterative methods and a perturbation approach is recommended.

Descriptors :   *TOMOGRAPHY, *INTERFEROMETRY, AERODYNAMICS, ALGORITHMS, COMPUTER APPLICATIONS, COMPUTERS, CONVOLUTION, DENSITY, DIGITAL SYSTEMS, DISTRIBUTION, FLOW, HELIUM, HOLOGRAPHY, HYBRID SYSTEMS, ITERATIONS, JET FLOW, MEASUREMENT, OPTICAL EQUIPMENT, OPTICAL PROPERTIES, PERTURBATIONS, PULSED LASERS, REFRACTION, RESOLUTION, TURBULENT FLOW, FLOW VISUALIZATION

Subject Categories : Aerodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE