Analysis of the Laser Doppler Measurement Technique for Application in TurbulentFlows

摘要

Laser Doppler Anemometry (LDA) has proven to offer the potential of being a nonintrusive, reliable measuring technique for turbulence measurements. In this thesis the Laser Doppler measurement technique will be evaluated for measurements in general turbulent flow where mean velocities, turbulent energy, turbulent shear stress, temporal and spatial correlations are of interest. Several issues directly related to the measurement technique were treated, like the comparison of different calibration techniques, and experimental studies on the influence of noise, bias-effects and fringe gradients on LDA measurements. As test cases for the LDA, measurements were conducted in three different flow configurations featuring different turbulence levels and Doppler signals with different SNR.