| The flow-induced vibration response characteristics of hydrofoils are significant to the ship engineering application research in vibration and noise reduction.The elastic vibration response and stress state caused by vortex motion have a non-negligible influence on the structural design of ship propeller.At the same time,the relationship between wall disturbance and the cavitation performance is worth for consideration for the marine structure improvement.In addition,as the important liquidgas conversion process,fluid-induced cavitation has been difficult to suppress or utilize in the fluid machinery operation.When the cavitation is tightly coupled with structural vibration,the complex hydrodynamic load characteristic and the flow field motion status change have significant effect on the hydrofoils.Because the numerical simulation method can directly obtain the pressure information of any flow field space according to the discretized fluid field,the relevant application into the fluidstructure coupling problem can ensure the reliability and visibility of research.In this paper,the NACA0009 trailing edge truncated hydrofoil section is concerned,the DES SST k-ω turbulence model is adopted to simulate the vortex shedding and near-wall flow characteristics under different flow velocity,and the finite volume solid stress model is coupled for the elastic vibration computation.The comparative analysis of the non-cavitation fluid-structure coupling numerical simulation and the rigid hydrofoil hydrodynamic numerical simulation was carried out based on the three-dimensional model and two sides constrains.The flow-induced vibration response analysis of the three-dimensional elastic hydrofoil considering the Schnerr-Sauer cavitation model was carried out.The fluid structure interaction study of the cavitating cantilever three-dimensional trapezoidal hydrofoil was also carried out for the local flow status and load characteristics.The main research content are as following:(1)Numerical simulation analysis for the hydrodynamic load and vortex shedding behavior of the elastic NACA0009(mod)hydrofoil with two sides constrained under different angles of attack and flow velocity were carried out,and the hydrodynamic performance difference between rigid-elastic hydrofoil was evaluated.The Fast Fourier Transition and vibration modal analysis obtained the resonance and frequency lock-in phenomenon of the coupled system.Based on the time-domain characteristic of the periodic lift load,the flow characteristics and motion trend were analyzed.(2)With the consideration of cavitation model,the numerical simulation study was carried out on the vibration response and flow field characteristics of the fluid-structure coupling system,and the hydrodynamic load of the elastic hydrofoil under different flow field pressures was evaluated.Carried out the analysis and processing of time-frequency domain vibration response load signal including structural load,flow load,structural vibration and flow state.The motion characteristics of the local cavitation flow and the cavity distribution are studied.Combined with the pressure frequency domain characteristics of the local flow field near the wall of the hydrofoil,the differential flow status at different position around hydrofoil is analyzed.(3)Concentrating on the structural material properties and geometric characteristics affecting the hydrodynamic response of elastic airfoil structure and its turbulence field problem,the research about of elastic materials affect(stainless steel and aluminum)on the constrained hydrofoil based on the cavitating coupled system is carried out.The influence of the foil spanwise geometry influence on the flow field motion trend is studied.The characteristics of the hydrodynamic load and the corresponding and local stress state of the cantilever trapezoidal structure coupled with cavitation flow are discussed.Combining the local flow status with the three-dimensional cavitation and vortex structure,the relevant time-domain trend is elaborated. |
PDF Full Text Request