Effects of burst detection and analysis upon turbulence measurements for laser Doppler anemometry

This study shows that for turbulence measurements made using laser Doppler anemometry, errors associated with the frequency analyzer's resolution can be present. Since all analyzers are based upon some digital clock, the mini mum clock cycle is proportional to the finest frequency resolution (f(r)) p ossible. It was found that if the frequency histogram spaned less than 16f( r) for +/-3 sigma, then the calculated values for all of the Reynolds stres s tensor components will be in error. This was observed for a counter syste m and a correlator system. The correlator system interpolated to less than one clock cycle, but the interpolation did not seem to help in the eliminat ion of the errors. (C) 1999 Elsevier Science Ltd. All rights reserved.