Table 1 

 Values of U* , z , and r 2 for Vertical Flow Speed Data 





v mid 



Number of 



U A 



z o 





cm/sec 



Profiles 

 5 



cm/sec 

 1.13 



cm 



r 2 



22 



0.0036 



0.98 



43 



47 



2.26 



0.0046 



0.97 



59 



4 



3.36 



0.0090 



0.97 



74 



48 



3.68 



0.0036 



0.96 



41. The following procedure was used in the testing of each nozzle: 



a. The equilibrium design flow condition was established and 

 defined by achieving consistent vertical profiles of flow speed 

 taken along the center line of the test section (Sections A and 

 B) . If the vertical profiles at Sections A and B differed sig- 

 nificantly (more than 5 percent) from the design flow, the 

 discharge was either increased or decreased until the desired 

 speed profiles were obtained. Typically, the profile was 

 measured at eight points. 



b. Vertical profiles of flow speed, consisting of eight points 

 with increasing spacing from the bottom, were measured at the 

 control location (Section A). This profile defined the refer- 

 ence flow profile without the trap in the tank. 



c. The rack with the nozzle to be tested was placed at the test 

 section (Section B) , and the vertical profile of flow speed was 

 measured at Section A. If the speed at any location differed 

 by more than 5 percent from that of the reference profile 

 measured in step b, the water level was lowered (to increase 

 the discharge and compensate for the flow resistance caused by 

 the trap) until all measurements fell within this tolerance. 

 The water level was never lowered more than 1.3 cm. Because 

 flow speeds were measured below the elevation z = 26.4 cm in 

 obtaining vertical profiles, lowering of the water level did 

 not require modification of the usual measurement point eleva- 

 tions . 



d. The flow speed at points distributed uniformly across the area 

 of the streamer nozzle was measured (3, 4, or 9 points, 

 depending on nozzle size and geometry) . These point measure- 

 ments defined the flow field directly in front of the nozzle. 



e. The rack and nozzle were removed, and the reference profile was 

 reestablished at Section A. 



30 



