ABSTRACT 



A procedure and numerical results are presented for the 

 prediction of the steady pressure distribution on a rotating 

 propeller blade surface based on lifting surface theory. A 

 computer code, named the Propeller Steady Pressure (PSP) 

 program, has been developed by extending the existing pro- 

 peller analysis program, PSF, based on vortex/source lattice 

 techniques, developed at the Massachusetts Institute of 

 Technology. Predictions by PSP are compared with selected 

 experimental values that are believed to be accurately and 

 reliably measured. Comparisons are also made between PSP 

 predictions and other theoretical predictions. The pre- 

 dictions by PSP are generally in good agreement with experi- 

 mental values and with other prediction methods except for 

 the tip region where current procedures may not be accurate 

 enough to represent the actual flow. 



INTRODUCTION 

 Knowledge of the pressure distribution on the propeller blade surface is 

 essential to understanding cavitation phenomena, boundary layer characteristics 

 and stress on blades. Measuring the pressure distribution on a rotating blade is 

 extremely difficult and time-consuming, and even then the reliability and repeat- 

 ability of the experimental data are often questionable. Nevertheless, a number 

 of experimental results of reasonable reliability are available, such as the ones 



•la 

 6 



1* 2 3 4 5 



obtained by Mavludoff, Kato, Yamasaki, Takei et al., Jessup, and Versmissen 



and Van Gent. 



The ability to predict the blade pressure distribution reliably and accurately 

 is also highly desirable. Many institutions throughout the world have their own 

 prediction methods; most of them are based on lifting-surface methods such as those 

 of Okamura, Kuiper, Brockett, and Tsakonas et al. and a two-dimensional pro- 

 cedure with some empirical corrections for three-dimensional effects by Bahgat. 



In this report, a procedure is presented to predict the pressure distribution 



on the propeller blade surface operating in steady flow based on the discrete 



12 

 vortex/source lattice method developed by Greeley and Kerwin. The discrete 



vortex lattice method has been used in the field of aerodynamics as early as 1943 



*A complete listing of references is given on page 15, 



