13 



■=■ Turbulence Rod Supported by 



Towing Carriage in C_ Plane of Model «» 









f 







/" 



L.W.L. 



> 









1 2" 



1 * 



— = -z-tt" 



J 









? 









) 





J 





Stations 4 i 



> 





1 





3"~* 



6"-* 





H- t 



r— 

 24" — » 





Figure 9a - Positions of Turbulence Rod, Corresponding to 2k, k8, and 

 192 Hod Diameters Forward of Model Stem 



-3 0"- 



0.032" Trip Wire 



Stations 6 4 2 



•-I.25* 



Figure 9b - Location of Trip Wire at 5 Percent of Length from Bow 

 Fine Grain Sand Strip ~, 



/ L.W.L. 



Stations 6 4 2 



' 1*1.25-* 



Figure 9c - Location of Sand Strip; Average Grain Diameter, 0.028 Inch 



Figure 9 - Details of Devices Used to Stimulate A 

 Turbulent Boundary Layer on Tanker Model 



ANALYSIS OP RESULTS OP BOUNDARY- LAYER SURVEY 



THEORETICAL BACKGROUND 



A well developed theory of the stability of laminar flow exists and 

 may be put to use in the interpretation of results of these model experiments. 

 It appears worth while at this point to give a brief summary of this theory. 

 An extensive amount of literature has accrued during the past 70 years on the 

 subject of laminar stability. A recent and very thorough treatment has been 

 rendered by C.C. Lin 4 and much work has also been done by Schlichting which is 

 conveniently summarized in Reference 5- 



STABILITY THEORY OF LAMINAR FLOW 



Modern theory holds that transition from laminar to turbulent flow 

 is the result of a stability phenomenon. The most successful mathematical at- 

 tacks on the problem have been those in which a small disturbing flow, or 



