Yamazaki 



<^=0, -Kfz=0.200 for Propeller M^ 



*=0, -Kfi =0.145 for Propeller Mji 



Rmx 

 Rh i). 



R^ 



1.2 

 1.1 

 1.0 

 0.9 

 0.8 - 

 0.7 - 



0.75 



1.00 



1.25 



0.75 



1.00 



1.25 



0.75 



1.00 



1.25 



0.75 



1.00 



1.25 



Fig. 



16 - Ratios of the bearing forces versus the 

 blade area ratio for a = 



CONCLUSION -~ ' - \ 



In the case of a ship with a single propeller and a single rudder being moved 

 straight with a constant velocity by rotating the propeller with a constant angular 

 velocity in unlimited still water, a general theory was developed for the flow 

 field around the ship and then the forces and moments acting on the hull, rudder, 

 and propeller on the basis of ideal fluid dynamics, in which the mutual interac- 

 tions among these parts were taken into account generally. The flow field around 

 the ship was determined so as to satisfy the boundary conditions on the surfaces 

 of the three parts simultaneously and was assumed to be composed of the irrota- 

 tional velocity field and the viscous velocity field. The viscous velocity field and 

 its interaction with the irrotational velocity field were assumed in appropriate 

 forms not to contradict with the boundary layer and wake theory. Then, by com- 

 paring the characteristics of the flow around a ship with a propeller and a rudder 

 with those around a ship from which the propeller was taken off, we derived the 

 general mathematical expressions for the differences of the forces and moments 

 acting on the hull, rudder, and propeller between these two ships. Thus we ob- 

 tained the unsteady propeller forces, which were subdivided into the surface 



80 



