When measuring local velocity components of a flow with a laser anemometer, the control volume is necessarily of finite size. If this volume lies across a mean velocity gradient, particles crossing the control volume will have a range of velocities. As a result, the probability density function of a velocity component is broadened and skewed in comparison with that obtained from an ideal point measurement. This report derives formulae for "gradient broadening" corrections to measured mean and rms velocity components for arbitrary velocity profiles. Their application suggests that the correction to mean velocity can be made negligible except when the measuring volume is not small relative to the flow dimensions;correction of the rms velocity components is more significant, and can be obtained by a piecewise linearization of the mean velocity profile.
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