Correlation of Theoretical Predictions of Propeller-Induced Hull Pressures with Available Data.
STEVENS INST OF TECH HOBOKEN NJ DAVIDSON LAB
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A method has been developed to calculate the blade frequency point pressure on a hull surface in the presence of a propeller and a free water surface. The approach is based on that previously employed in calculating the propeller-induced hull forces in which the hull is represented by a source distribution smeared over the hull surface whose strength is determined through the solution of a Fredholm integral equation of the 2nd kind in terms of specified propeller-induced velocities. Point pressures are determined by superposing the free-space pressure emanating from the propeller through its fanning action on the pressure due to the diffraction potential. A series of calculations was performed for the case of a model tanker tested extensively at the Norwegian Experimental Tank Ship and Ocean Labroatory, Norwegian Hydrodynamic Laboratories. The agreement between experimental and predicted values varies from point to point in general, the maximum deviation of amplitude is between or - 30, but the phases are in poor agreement. A new method is suggested in which the hull is represented by a doublet distribution rather than a source distribution. This approach which reduces computing time considerably permits improved accuracy and results in much better correlation between experimental and calculated values.
- Marine Engineering
- Fluid Mechanics