233 



FIGURE 12. Afterbody profile view of DTNSRDC 

 model 5365 fitted with a rake of five-hole 

 pitot tubes on the starboard shaft. 



FIGURE 13. Double model installed in DTNSRDC 

 wind tunnel. 



the use and calibration of five-hole pitot tubes. 



The boundary layer velocity profile measure- 

 ments on the double model, Model 5365, in the wind 

 tunnel were obtained using a hot wire anemometer. 

 The model was mounted on its side and the anemom- 

 eter was moved in the horizontal direction by a 

 rack and pinion drive . The rack and pinion , with 

 its stepping motor, allowed the position of the 

 anemometer to be set to within a fraction of a 

 millimeter. 



Figure 13 shows the double model mounted in the 

 wind tunnel. The vertical strut at the stern of 

 the model is the support for the anemometry, and 

 the bottom horizontal bar is an arm to steady the 

 strut. The top horizontal bar is the traversing 

 arm on which the hot wire anemometer is mounted. 

 A close-up of the hot wire anemometer is shown in 

 Figure 14; a centimeter scale is shown in the 

 background of the photograph. 



FIGURE 14. Hot-wire anemometer probe used for model 

 wind-tunnel boundary layer profile measurements. 



