Propeller Excitation and Response of 230000 TDW Tankers 



5. The type and extension of the cavitation, as observed on the full 

 scale ship (six-bladed propeller) and in the cavitation tunnel, are rea- 

 sonably similar for the fully loaded condition. In the ballast condition, 

 however, cavitation is more extensive on the ship than on the model 

 propeller. 



6. The observed type and extent of cavitation were confirmed with 

 reasonable accuracy by the calculations illustrated in the present 

 paper. 



7. The pressure impulses of both blade and twice blade frequency, 

 recorded onboard the ship, correlated well with those calculated with 

 the use of the method developed for the calculation of pressure fluc- 

 tuations from cavitating propellers. 



VIII. ACKNOWLEDGEMENT 



The investigation was carried out in close cooperation between 

 the initiator, Uddevallavarvet AB, the Swedish State Shipbuilding Ex- 

 perimental Tank and Det norske Veritas. The work has been sponsor- 

 ed partly by the Swedish Board for Technical Development and partly 

 by the shipyard and the shipowner companies involved, i.e. A/S Thor 

 Dahl, Sandefjord and Odd Godager and Co, Oslo. 



The authors would like to express their sincere thanks to all 

 those members of the staffs of the above-mentioned establishments 

 and companies, who have taken part in the investigations and contri- 

 buted to the analysis of the material. 



LIST OF SYMBOLS 



A /A = developed blade area ratio 



C = dL/— —pc db V = lift coefficient 



1 2 



C = (p-p )/~r~ pV = pressure coefficient 



p o 2 



c = blade chord 



D = propeller diameter 



dL = lift of profile 



603 



