28 



Values of \p are computed directly from the measurements of Schubauer and 

 Klebanoff by substituting data into Equation [67] and performing the indicated 

 integrations numerically by Simpson's rule. For comparison, values of ip are 

 obtained from the analytical formulations of I based on the methods of 

 Fediaevsky and of Ross and Robertson by inserting values of a and from the 

 experimental data into Equations [64], [65], and [66]. As seen in Figure 13, 

 in which \p is plotted for various stations along the boundary layer, both of 

 the Fediaevsky formulations show poor correlation with experimental points 

 while the Ross and Robertson formulation shows only fair agreement. It is 

 observed that except for experimental error the value of \p is practically con- 

 stant for different stations along the boundary layer. This suggests that 

 using a value of >p independent of the effects of pressure gradient ought to be 

 sufficiently accurate for most technical problems encountered. 



H£ 



U => 0.015 





^r Fediaevsky 3 Conditions 

















Fediaevsky 5 Conditions 

















Ross ft Robertson 

















< 



\~f * 



—y Experiments Points 





• 



• 



• 









V 







• T ~i 



t — • — 



21 22 



Station x in feet 



Figure 13 - Integral of Shearing Stresses Across the Boundary Layer 

 for Data of Schubauer and Klebanoff, Reference 25 



Before deciding on values of ip for pressure gradients in general, 

 it will prove fruitful to investigate the values of ip in a zero pressure gradi- 

 ent. From Equation [68] ip for a zero pressure gradient or ip Q may be written 



as 



k = 



PU 2 6 



[69] 



