34 



10 

 u> 

 o 



o 

 8 



a 

 c 

 o 



1/32" Trip Wire Around 

 Girth at Station 1 



\ 













\ 















( 











\ 



■a 





s 



a. 



e 



o 

 o 2 



o 



c 





N 



— "■ 





k 



[A 











\ 





4xl0 6 6 8 10 12 14 



Model Reynolds Number 



1/8" Turbulence Rod Held Vertically 

 >v 48 Diameters Forward of Bow 



\ 

 i 



\ 











_--■ 



- —0 



( 



"^ 





, 











\ 



t 















_\ 















7/8" Sand Strip Around 

 Girth at Station 1 







































T"—Jf — 



"o— - 





N.— ^* 



^?^- 













V 



4X10 6 8 10 12 I 



Mddel Reynolds Number 



2 







4XI0 6 6 8 10 12 14 16 



Model Reynolds Number 



Definitions 



ac is the measured increase in model resistance 

 ioo -jr 1 with turbulence stimulation in percent of the 

 * computed model frictional drag. 



is the measured percent increase in model re- 



I00 c r ^ sistance with correction for the stimulator; 



f see Equations [23], [24], and [25]. 



* i9 the computed increase in model resistance 

 ,_o— o loo A f f obtained from hot-wire survey of the boundary 



c 'f layer with and without stimulation of turbulenaa. 



The computed model frictional drag is B.'. - 12 lb at 

 model Reynolds number R = 14.7 x 10 6 (3.50 knots) 



Figure 22 - Curves of Increase of Resistance of Tanker Model Obtained 



with Various Stimulators as Derived from Drag Tests 



and Boundary Layer Surveys 



CORRECTION FOR TURBULENCE ROD 



Direct calculation of a correction for the undesirable effects of 

 the turbulence rod on the flow about the ship model Is very difficult. The 

 rod produces a wake or a reduction in the flow velocity in a narrow band at 

 the bow of the model. Quite recently measurements have been made in the TMB 

 model circulating-water channel of the wake behind a circular cylinder. At a 

 position 48 diameters aft of a 1 /8-inch rod the average value of the velocity 

 is about 0.93 U for a rod Reynolds number of 1900. At the bow of the ship 

 model this wake effect is distributed over a width of about one inch. One 

 might imagine that the wave resistance of the model is also influenced by the 

 wave pattern set up' by the rod. Some idea of the magnitude of the combined 

 wake and wave effect of the rod on the model resistance may be obtained from 



