29 input voltage. From this, the threshold value of the input is found to be approximately 0.6 V.


Figure 3-6 Block diagram for calibration and velocity measurement for the water tunnel.


  60

  50
N
-r
ci,4 C=30

"0 20
0
  10


0. 6


  0.4
  0

0.2


2          4          6
   DAQ voltage (Volts)


Figure 3-7 Motor frequency of water tunnel plotted as a function of DAQ input voltage. Velocity Profiles

    For the velocity profile measurement of the water tunnel, the pitot-static probe is traversed from the bottom of the water tunnel until just below the air water interface in steps of 2 mm. The voltage v, is steadily increased from 1-8 V DC in steps of 1 V. An