Design of LV experiments for turbulence measurements

In planning laser velocimeter experiments for turbulence measurements, the major contributors to turbulence bias errors are processor frequency limitations, measurement volume polar response, PMT SNR ratio, and digital measurement resolution. In the Lockheed LV system the major controlling influence available to the experimenter is the apparent fringe velocity. By identifying the sources of these bias errors, the paper presents a technique for selecting fringe velocities which minimize the effects of these biases and quantifying (to some extent) the remaining errors. In addition, guidelines are provided for the technical development of LV systems which will be able to make accurate measurements in very-low-turbulence flows.