Laser velocimeter data acquisition, processing, and control system

The use of a mini-computer for data acquisition, processing, and control of a two-velocity-component dual beam laser velocimeter in a low-speed wind tunnel is described in detail. Digital stepping motors were programmed to map the mean-flow and turbulent fluctuating velocities in the test section boundary layer and free stream. The mini-computer interface controlled the operation of the LV processor and the high-speed selection of the photomultiplier tube whose output was to be processed. A statistical analysis of the large amount of data from the LV processor was performed by the computer while the experiment was in progress. The resulting velocities are in good agreement with hot-wire survey data obtained in the same facility. (auth)