Accession Number : ADP008932

Title :   Simulation and Experimental Verification of Statistical Bias in Laser Doppler Anemometry Including Non-Homogeneous Particle Density,

Corporate Author : QUEENSLAND UNIV BRISBANE (AUSTRALIA) DEPT OF MECHANICAL ENGINEERING

Personal Author(s) : Fuchs, W. ; Albrecht, H. ; Nobach, H. ; Tropea, C. ; Graham, L. J.

Report Date : 23 JUL 1992

Pagination or Media Count : 6

Abstract : The correlation between the measured velocity component and the instantaneous particle rate in laser anemometry leads to a statistical bias of most commonly used estimators. An additional bias may occur in non-homogeneously seeded flows if a correlation exists between the velocity and the particle density. These statistical bias effects are investigated using numerical simulations. Models for the particle arrival statistics are derived using autoregressive (AR) time series of the first order, generated for three velocity components with prescribed means, Reynolds stress tensor and time scales of the three normal stress tensor terms. The expected results obtained with commonly used processors and sampling techniques are investigated for various prescribed homogeneous and inhomogeneous particle densities. The numerical results are compared to existing theoretical solutions and to some initial experimental results, obtained in an axisymmetric, co-flowing free jet. Some comparisons between one-dimensional and three-dimensional flowfields are also presented. (Author)

Descriptors :   *LASER ANEMOMETERS, BIAS, PROBABILITY DENSITY FUNCTIONS, FLOW FIELDS, PARTICLES, DOPPLER EFFECT, BIAS, SHEAR STRESSES, GERMANY.

Subject Categories : Optical Detection and Detectors
      Statistics and Probability

Distribution Statement : APPROVED FOR PUBLIC RELEASE