Morgan and Caster 



ratios of 0.065, 0.025, and -0.022, respectively. Each of the ducts were designed 

 to have a constant chordwise circulation distribution. 



The experimental pressure distribution, along with two sets of theoretical 

 values from linearized theory, are shown in Figs. 8, 9, and 10 for these ducts at 

 zero angle of incidence. The solid lines are the theoretical results from Ryall 

 et al. (35), who assumed that a constant chordwise circulation distribution pro- 

 duces only 74% of its theoretical loading. They based this assumption on the 

 fact that in two dimensions the constant chordwise circulation distribution 

 (NACA a = 1.0 mean line) produces only 74% of its predicted lift (36). Thus, in 

 determining the pressure distributions shown by the solid lines in Figs. 8, 9, 

 and 10, only 74% of the contribution from the ring vortices was used in calculat- 

 ing the pressure distribution. The dashed lines on these figures are the theo- 

 retical pressure distribution calculated by the linearized theory of Ref. (33) with 

 a nonlinear correction. All the predictions shown in these figures were made 

 using the Bernoulli equation without linearization. 



Fig. 8 - Pressure distribution on ARL duct Bl at 

 zero angle of attack (a = 0) 



The theoretical predictions for this set of tests are quite inconclusive. The 

 predicted pressure distribution for duct Bl, decelerating type, is satisfactory 

 except near the leading edge if 74% of the contribution from circulation is used 

 in the calculation (35), Fig. 8. For duct B3, accelerating type, the prediction is 

 unsatisfactory on the inside of the duct using the same procedure, Fig. 10. On 



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