Wereldsma 



Fp = forward perpendicular 



I = moment of inertia 



M = mass 



P - pitch of propeller 



Q = torque, torque of propeller . ;- 



R = propeller radius 



T = propeller thrust 



z = mechanical impedance 



n = speed of rotation 



X = axial vibratory motion of the propeller 



z = blade number of the propeller 



d = angular position , v: i: ^i / I; ,,.. - -f v: 



cp = rotational vibratory motion of the propeller 



Subscripts 



A refers to aft propeller 



F refers to forward propeller 



T refers to turbine 



1 refers to aft propeller shafting system 



2 refers to forward propeller shafting system 



Superscripts ■• '- 



G refers to gearing ^ 



INTRODUCTION 



During the past decade much knowledge has been gained about the vibratory 

 effects of ship propellers operating in the wake of a hull. Theoretical as well as 

 experimental techniques have been developed for the study of propeller- generated 

 vibrations. 



236 



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