Vogel and Patterson 



up to the second slot is elliptical in shape, the section from the second to the fifth 

 slot is cylindrical and the tail section is faired to a pointed trailing edge. Each 

 slot can be individually adjusted, and the polymer solution can be injected through 

 each slot independent of the flow through the other slots. Only the nose slot was 

 used for this work. 



The wings are elliptical sections symmetrical about the line joining the lead- 

 ing and trailing edges. They are mounted on the body so that the planes of sym- 

 metry of each wing pass through the centre-line of the body. The wings serve 

 two purposes: to support the body in the three -component force balance, and to 

 act as a shield for the lines running to the slots. Three lines are in one wing and 

 two lines in the other. 



The pumping system and tunnel set-up are shown in Fig, 3. In order to min- 

 imize the possibility of degrading the fluid before it is injected into the boundary 

 layer it was decided to use air pressure as the pumping force. When the fluid 

 is mixed it is drawn into the pump by reducing the air pressure in the pump. To 

 inject the fluid into the boundary layer a known positive pressure is applied to 

 the pump. The pressure is adjusted until the desired flow rate is achieved. The 

 flow rate is determined by using a stopwatch to measure the time required for a 

 known volume of the fluid to leave the pump. 



Fig. 3 - Water tunnel and equipment used for 

 drag reduction experiments 



978 



