Accession Number : ADP009032

Title :   Particle Induced Limits of Accuracy in Laser Doppler Anemometry,

Corporate Author : KARLSRUHE UNIV (GERMANY F R) INST FUER HYDROMECHANIK

Personal Author(s) : Ruck, B. ; Pavlowksi, B.

Report Date : 23 JUL 1992

Pagination or Media Count : 8

Abstract : The laser Doppler anemometry (LDA) is one of the most advanced optical measuring techniques for flow velocities. Thus, laser Doppler anemometry is wide-spread in use in the laboratories of industry and universitarian research institutions. Based on innumerable applications in the past, there is no doubt that laser Doppler anemometry is one of the most accurate flow measuring techniques. However, recent investigations have shown that the period lengths of LDA signal bursts are not as constant as one might expect within the individual burst. This can induce an additional scatter in the signal frequency and in the determination of flow velocity from individual bursts. This paper describes experimental investigations which show qualitatively and quantitatively that the particle passage through the laser beams shortly before the point of superposition, i.e., the LDA measuring volume, yields a distorted LDA fringe pattern which results in a scatter of the measured velocity data for those particles, passing the center of the measuring volume at the same time. (Author)

Descriptors :   *LASER ANEMOMETERS, *OPTICAL SCANNING, RESONANCE SCATTERING, MEASUREMENT, ACCURACY, PARTICLE FLUX, SIGNAL PROCESSING, VARIATIONS, OPTICAL IMAGES, PHASE DISTORTION, FLOW FIELDS, ERROR ANALYSIS, FAST FOURIER TRANSFORMS, SIGNAL TO NOISE RATIO, EXPERIMENTAL DATA, GERMANY.

Subject Categories : Optical Detection and Detectors
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE