Bavin, Vashkevich, and Miniovich 



to the equations for a wide-bladed propeller, the calculated pressure amplitudes 

 are in perfect agreement with the experimental ones (see the dash-dot curve in 

 Fig. 4). Corresponding calculations for the case of a propeller operating in a 

 wake cannot be made at present because of the lack of precise knowledge of the 

 chordwise distribution of the loading on the blade of a propeller operating in a 

 nonuniform flow. 



The curves in Fig. 5 show the relative effect of flow nonuniformity on pres- 

 sure amplitudes for a propeller behind a screen. It can be seen that for this 

 particular case the theory underestimates the relative effect as compared with 

 the experimental data. 



ezp«rlnental raluea 



Fig. 5 - Relative effect of flow nonuniformity 

 for a propeller behind a screen: 1, maximum 

 wake; 2, minimum wake 



A more complete experimental investigation of the effect of nonuniformity 

 on vibratory pressures should be carried out in the future with propellers hav- 

 ing various geometrical elements. 



CONCLUSIONS 



1. The equations derived in this paper make it possible to compute the am- 

 plitudes of the blade -frequency harmonics of the pressures generated by a ship 

 propeller operating in a wake. It is shown that within linearized theory the re- 

 lation between induced pressure and nonstationary circulation around the pro- 

 peller blade remains the same as in the case of uniform flow conditions. 



12 



