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Hydrodynamic coefficients of compound circular cylinders in heave motion

University of British Columbia

The added mass and damping coefficients of a compound circular cylinder in heave motion are computed theoretically using a semi analytical potential flow method. The method uses continuity of pressures and velocities between adjacent regions of the flow field. The heave exciting forces on the compound cylinder are calculated from the heave damping coefficient. The hydrodynamic coefficients and the heave exciting forces are compared to theoretical results obtained from a boundary element method. The hydrodynamic coefficients of the compound circular cylinder are determined experimentally by forced harmonic oscillation of the cylinder model. The wave height at a point in the flow field was also measured during the experiment. The effects of variation of amplitude and frequency of oscillation and draft are also studied experimentally. The results are compared to the theoretical predictions. The heave exciting forces on a compound cylinder model due to small amplitude, sinusoidal waves are measured experimentally in a towing tank. The results are compared to predictions by the theoretical method presented in this thesis and by a boundary element method. The heave exciting forces on single and double cylinder models are also determined experimentally. These results are compared to theoretical predictions by a boundary element method. The comparisons between theory and experiment show the applicability of linear potential flow theory in the determination of the hydrodynamic coefficients of the compound cylinder model.

Text

2010-05-24

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http://hdl.handle.net/2429/24957

Mechanical Engineering

University of British Columbia

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