Publication Date:
2019-07-13
Description:
An experimental investigation was conducted in the 14- by 22-foot subsonic tunnel at NASA-Langley Research Center to measure the inflow into a scale model helicopter rotor in forward flight. These inflow measurements were acquired utilizing a two-component laser velocimeter, and the data were processed by a frequency-domain processor (FDP). As a subset of the experiment, a time-domain counter processor was utilized simultaneously with an FDP to make a comparison of the two processors possible. The results indicate that the FDP had a marked improvement in processing capability in conditions of low signal-to-noise ratios and had a reduction in the number of erroneous data points acquired. However, the FDP yielded a lower data rate in comparison to the counter when signal-to-noise ratios were high. Comparison of the data sets shows that the FDP consistantly measures velocities which are 0.7 percent higher than those measured by the counter processor.
Keywords:
INSTRUMENTATION AND PHOTOGRAPHY
Type:
ICIASF ''91 - International Congress on Instrumentation in Aerospace Simulation Facilities; Oct 27, 1991 - Oct 31, 1991; Rockville, MD; United States
Format:
text
