Vibrations of simplified rudder induced by propeller wake

Abstract

Severe wake-structure interaction induces intense vibrations and noises. In this study, the rudder is simplified into a plate fixed at two ends. The vibrations of the plate operating in the propeller wake are analyzed. Detached eddy simulation is employed to simulate the turbulence in the flow field and propeller wake. The structural deformation equation is solved via the finite volume method. The pressure fluctuations in the propeller wake and the vibrations on the plate are investigated. The results show that the excited vibrations coexist with natural vibrations on the plate. The natural vibration mode can be occupied by the excited vibration. The lock-in regime between the excited vibrations and natural vibrations leads to weaker vibration at excitation frequencies. The vibration mode induced by the hub vortex transfers to the first natural vibration mode when the shaft frequency approaches the first natural frequency. The vibrations on the plate are more dominant at the first natural frequency in the approach of the shaft frequency to the first natural frequency. This investigation of plate vibrations induced by the propeller wake contributes to the structural design of the ship.