Singing problem of high efficiency propeller

摘要

The cause of propeller singing could be explained by the resonance between Karman vortex street from the trailing edge of 0.55R~0.6R and the natural frequency of the blade. Therefore the modification of shape around the trailing edge by grindingcould almost prevent the singing.However, recently there were many cases that the propeller singing could not be prevented by the usual measure. In this study, the characteristics of the recent singing and its preventive measures are considered using FFT analyzer of noise occurred onsome large ships. In consequence, one of the new anti-singing method leading to good results on some applied ships is shown.