TURBULENCE IN MEAN 

 FLOW DIRECTION = v/o^-i 



■SENSOR A 

 -0.04 TYPICAL SPACING (1.0 mm) 



TURBULENCE IN DIRECTION 

 PERPENDICULAR TO MEAN 

 FLOW = s/v^ 



PROBE STEM 



FILM SENSOR: 0.002 IN. DIA (0.05 mm) 



Figure 2 - Schematic of a Two Element Sensor Alined 90 Degrees 

 to Each Other and 45 Degrees to Probe Axis 



The frequency response of the anemometer system, for reliable measure- 

 ments claimed by the manufacturer, is to 200 kHz. Calibration of the "X" 

 hot film was made before and after each set of measurements. It was found 

 that the hot-film anemometer system had a +0.5 percent accuracy, +0.75 

 ft/sec (+0.23 m/s) accuracy at the free stream velocity of 150 ft/sec 

 (45.72 m/s), during the entire experiment. An estimate was made of the 

 cross-flow velocity by yawing the "X" hot-film probe in the freestream. It 

 was found that the crossflow velocities were about one percent of the 

 freestream velocity. 



The linearized signals were fed into a Time/Data Model 1923-C real- 

 time analyzer. Both channels of the analog signal were digitized at a 

 rate of 128 points per second for 8 seconds. These data were immediately 

 analyzed by a computer to obtain the individual components of mean 

 velocity, turbulence fluctuation, and Reynolds stress on a real time basis. 



