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SECURITY CLASSIFICATION OF THIS PAGE fHTian Data Entered) 



(Block 10) 



lED funding under Element 62766N, Work Unit No. 1552-119, NAVMAT 

 DIRECT Laboratory Funding under Element 62543N, Work Unit Nos. 

 1520-004 and 1500-200. 



(Block 20 Continued) 

 velocities and the modified hull pressure distribution are computed with 

 appropriate corrections to the hull singularities. The axial force is 

 then derived by integration of the pressure on the hull and also by appli- 

 cation of the steady-flow Lagally theorem. 



The usefulness of this technique is illustrated by its application to 

 several stern propeller-body-of-revolution configurations. It is shown 

 that stern appendages contribute up to 25 percent of the total thrust de- 

 duction. The relative contributions of propeller loading and thickness 

 are examined. It is found that the lifting-surface representation predicts 

 10 to 20 percent lower thrust deduction than the classical lifting-line 

 (sink disk) approximation. Calculations for a series of four raked pro- 

 pellers illustrate the significant (over 50 percent) attenuation of the 

 interaction force as rake is increased. It is concluded that the method 

 is useful for both the analysis of a given design and for parametric in- 

 vestigations of higher efficiency propeller-afterbody configurations. The 

 method may also be extended to treat contrarotating and ducted propellers. 



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SECURITY CLASSIFICATION OF*THIS PAGEfWhen Dale Entarad) 



