Additives Injected Into the Boundary Layer of an Underwater Body 

 30| — — I — I 1 r 1 1 



25 



20' 



Drog 

 Reduction -gms 



15- 



Tunnel velocity 600 cm/sec. 

 0.25mm. Nose Slot 



Polyox WSR-301 



Polyox WSR-205 



- Polyox WSR- 35 



-I u 



50 100 150 200 250 300 



Polymer concentration - ports per million by weight. 



Fig. 11 - Drag reduction vs polymer concentration 



there is some scatter in the data which could indicate that there is some degra- 

 dation of the fluid at the smallest slot opening, the main conclusion drawn is that 

 at these flow rates the important parameter is not the flow rate but the quantity 

 of the fluid injected. 



DEGRADATION OF THE POLYMER SOLUTION 



On several occasions a solution was mixed and for some reason left stand- 

 ing for three or four days in a metal container. A brown deposit was usually 

 found in the bottom of the container, and when the solution was used it was noted 

 that the drag reduction was less than that obtained with solutions which had been 

 standing less than 24 hours. These runs were not included in the foregoing fig- 

 ures. To determine the magnitude of this effect we did runs with a standard and 

 with a degraded solution; the results are shown in Fig. 16. No analysis of the 

 brown deposit was carried out. 



No experiments were carried out to determine the mechanical degradation 

 of the polymer solutions. 



DYE -INJECTION STUDIES 



In order to determine whether the gross structure of the boundary layer was 

 affected when the polymer solutions were injected, it was decided to dye the fluid 



985 



