Spectrum measurements with laser velocimeters

The length of time or number of samples required for a laser velocimeter experiment to attain a specified variability error level is determined. The study is based on available techniques for estimating turbulence point spectra with a Poisson sampling signal formalism. The discretized lag product technique is found to be the most efficient spectral estimator. The variability error theory developed by Gaster and Roberts (1975) for an exact lag product algorithm provides a practical formula for the discretized lag product algorithm.