In order to establish a optical measuring method of spatial turbulence scale, a new laser 2-focus velocimeter (L2F) system with the high optical SN ratio was developed. It consists of a couple of L2F system in which wide-stripe type high power semiconductor laser was installed. Flow velocities were measured simultaneously at two adjacent points in a circular air jet, and all these velocity data and their corresponding data sampling time were acquired in time sequence by a personal computer. The correlation-based slotting technique was applied for analyzing the spatial correlation of turbulence. Estimated spatial- and temporal- turbulence correlations were compared to those measured by the hot wire anemometer. It is clearly shown that a couple of L2F system in combination with the correlation-based slotting technique is very useful for turbulence correlation measurement.
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