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This paper surveys fluid dynamic-acoustic mechanisms that may explain low-frequent, broadband hull excitation experienced on board of ships and caused by propeller cavitation. Observations obtained from sea trials and model scale experiments are used to describe the hydrodynamics involved in each particular mechanism. The investigations are still ongoing and aim to identify causes of broadband inboard noise and vibration on passenger vessels in the frequency range of 20 to 70 Hz.

A potential-based lower-order surface panel method is developed to calculate the flow around a three-dimensional hydrofoil with an attached sheet cavity the leading edge. A Dirichlet type dynamic boundary condition on the cavity surface and a Neumann boundary condition on the wetted surface are enforced. The cavity shape is initially assumed and the kinematic boundary condition on the cavity surface is satisfied by iterating the cavity length and shape. Upon convergence, both the dynamic boundary condition and the kinematic boundary condition on the cavity surface are satisfied, and a re-entrant jet develops at the cavity closure. The flow at the closure of the cavity and the mechanism of the re-entrant jet formation is investigated. Good agreement is found between the calculated results and MIT’s experiments on a 3-D hydrofoil.