The expression is 



*«^-£M£)'~<'-/M$ 2 £ ( ~'* 



5* d /u^ 2 



dxl (19) 



2 dx \U C ' 



Once the value of x Q is determined, C F (S L _ x ) and C R can be obtained, using Equations 

 (16) and (10). The value of C R obtained should be the same for both tripped and untripped 

 (AC T = 0) models. 



When trips are located near the leading edge, and/or the trip has a high parasitic drag, 

 the computed value of x Q can become negative. When this occurs, the following approxima- 

 tion is made when computing C R from Equation (12) 



S L -x„ L- x„ 



The results obtained in Series 1 experiments were computed using the previously 

 described equations. However, in Series 2 experiments, whenever x was directly involved in 

 the calculations, it was replaced by the arc length along the meridian s. Thus the virtual 

 origin was located at a position s from the leading edge of the plate of width 

 27ry = S L _ x /(s L - s ), operating at a Reynolds number R s _ s = U Q (s L - s q )/p, where s L is 

 the total arc length of the model. This change was necessary to obtain results on the two 

 flat-faced models. To compare results, C R values were computed, using both s and x for 

 Models 5 through 7. There was a difference of approximately 1 percent in the values of C R . 



RESULTS 



TRANSITION LOCATIONS 



On Models 1, 2, 5, 7, and 9, laminar separation was predicted to occur on the forebody 

 sections of the models at the locations given in Table 4. For the Reynolds number range used 

 in these experiments, hot films located immediately before the predicted locations indicated 

 laminar flow. Hot film gages, located immediately aft of the predicted locations, indicated a 

 disturbed or turbulent flow. It was concluded from these measurements that transition was 

 occurring between these two gages and that separation was tripping turbulent flow, thus 

 justifying the use of the predicted laminar separation location as the transition location. 



15 



