Study On Flow-induced Vibration Of Elastic Propellers In A Nonuniform Inflow

The present research focuses on the flow-induced vibration of propeller blades under non-uniform inflow.Large eddy simulation(LES),finite element method/boundary element method were used to predict the vibration responses of the propeller blades under non-uniform inflows.The primary work includes,(1)LES and the corresponding signal processing method were used to calculate the pressure fluctuations and the wavenumber-frequency spectrums of the three dimensional NACA0015 airfoil.The effects of the non-uniform inflow on the pressure fluctuations and the wavenumber-frequency spectrums were also studied.(2)Numerical simulations were carried out using CFD and a combined finite element and boundary element method.The pressure fluctuations of the blade induced by the cyclic inflow were analyzed.A plastic and a metal seven-bladed highly skewed model propellers which have identical geometries were used in the simulations.The effects of the propellers' elastic properties on the vibration responses were carried out by comparing the vibration responses of the two propellers under different rotational speeds.(3).The axial velocity distributions of different cyclic inflows were measured using LDV.The vibratory strain and acceleration were measure by two different experimental methods.The propellers were accelerated through the flexible propeller's fundamental frequency to investigate the effect of resonance on vibration responses.(4)The vibration responses of the blades of the large diameter propeller were investigated numerically and experimentally.The variation characteristics of the unsteady forces were carried out by comparing the vibration responses of the different diameter propellers at the same operating condition.