Propeller -Induced Appendage Forces 



0.2 0.4 0.6 0.8 



Spacing/Propeller Diameter 



1.0 



Fig. 34 - Induced force ratio vs spacing ratio for a 

 three -bladed propeller upstream of an appendage, 

 transverse measurements, and an appendage angle 

 of 0° 



THEORETICAL STUDIES 



At the start of this overall program it was recognized that measurements 

 would be made of relatively small interaction effects, and since the work was 

 exploratory it would be important to have a guide as to the expected relative 

 magnitude and character of the various force components. Thus a coordinated 

 approach of combined theory and experiment was carried out, so that compari- 

 sons could establish a predictive tool for future studies. The theoretical study 

 described herein (abstracted from Ref . 5) is intended to determine the relative 

 magnitude of the transverse and axial forces acting on upstream appendages in 

 the presence of a rotating propeller without considering (for this present work) 

 the changing forces on the propeller blades due to the interaction. The mathe- 

 matical analysis of the flow problem is based on two-dimensional ideal non- 

 viscous flow for which potential theory is applicable, similar to the work on this 

 problem described in Refs. 1 through 4. 



205 



