McCormick 



Fig. 1 - Section of TRI-B body 



The purpose of removing the boundary layer is to stabilize the laminar 

 layer and prevent it from becoming turbulent. The slots and suction flow quan- 

 tity were chosen to prevent the Reynolds number based on the thickness of the 

 laminar boundary layer from exceeding a critical value. This prescribed value 

 and the means by which the slot geometry was chosen were based on the find- 

 ings of Loftin and Burrows as reported in Ref. 1. 



For testing, TRI-B is placed in a protective launching tube, lowered to a 

 depth of 400 ft and released. Its buoyancy of approximately 84 lbs propels it 

 vertically upward attaining a velocity at the surface of approximately 30 to 50 

 fps depending on whether or not laminar flow is achieved. 



HYDRODYNAMIC DESIGN OF BODY 



The method used to design the suction slots, i.e., their axial spacing, slot 

 width and suction flow quantity was based on the semi- empirical approach pro- 

 posed in Ref. 1. This reference relates experimentally the change in Reynolds 

 number, based on the boundary layer thickness, across a suction slot to the 

 amount of boundary layer flow removed through the slot. 



If AQ is the flux removed per unit length of slot, then Ref. 1 has determined 

 experimentally the ratio of s immediately after the slot, s^ to s immediately 

 before the slot, § j . 



^1 Qbl 



AQ 



< .275 



(1) 



QgL is the flux per unit width of fluid in the boundary layer. 



Again from the experimental results of Ref. 1, the power required for the 

 suction flow was calculated from an expression for the head loss across each 

 suction slot. According to the reference. 



1002 



