Vogel and Patterson 



Drag 

 Reduction gms 



1 r 



Tunnel velocity - 400om/sec. 

 0.25mm. Nose Slot 

 Flow rate - 30ml/sec. 



-Polyox WSR-301 



.n -Polyox WSR-205 



Polyox WSR - 35 



50 100 150 200 250 300 



Polymer concentration - parts per million by weight. 



Fig. 9 - Drag reduction vs polymer concentration 



Polyox WSR-301 



- Polyox WSR - 205 



- Polyox WSR -35 



50 100 150 200 250 300 



Polymer concentration - parts per million by weight. 



Fig. 10 - Drag reduction using polymer concentration 



concentrations were carried out to a flow rate of 50 ml/sec and the drag reduc- 

 tion was still increasing with increasing flow rate. There was some indication 

 that at flow rates higher than this a plateau was reached in the drag reduction. 

 Whether this is a real effect in the boundary layer or a limitation in the flow 

 through the tubes to the slot has not been determined. It has also been sug- 

 gested that increased turbulence in these tubes could degrade the polymer. 



The average velocities through the nose slot for these flow rates are; 87 

 cm/sec for 13 ml/sec, 154 cm/sec for 23 ml/sec, 200 cm/sec for 30 ml/sec, 

 and 335 cm/sec for a flow rate of 50 ml/sec. These injection velocities are com- 

 parable to the tunnel velocities at which these tests were run. 



Figure 15 shows the effect of increasing the slot width from 0.25 mm to 

 about 0.9 mm. Four flow rates were used with each slot opening, and although 



984 



