| Vortex shedding phenomenon is usually harmful. For example, like a cylinder in fluid, the vortices will shed alternating behind the cylinder when fluid flows. It can make the cylinder vibrate and generate the lift force in transverse direction and the drag fore in flow direction. The VIV (Vortex-induced vibration) causes fatigue damage to the structures and affects the duability, leading great difficulties to the maintenance. In ship engineering, related researches include the VIV of barrel-shaped mast under wind load and the VIV of riser under stream load. However, there is also a bright side in vortex shedding phenomenon. For instance, like a foil in horizontal flow, directions of lift and drag forces are changed along with directions of structure motion. Lift and drag forces can create propulsive force in horizontal direction under proper condition. In ship engineering, related researches are the applications of single foil oscillating propulsor and the WIG (Wing-In-Ground) thrusters. Therefore, based on numerical simulation, this paper studied vortex shedding phenomenon of barrel-shaped and foil-shaped structures, which revealed different features of static structure in flow and moving structure in flow.The main contents and conclusions are as follows:On one hand, this paper studied the VIV of a barrel-shaped mast, which displayed the drawback from vortex shedding phenomenon of static structure. And, HPD (High Precision Direct) integration scheme was selected into sloving the structural responses.1. This paper established the fluid-structure coupling model of VIV by wind when Reynolds number was in subcritical area. The structural responses of VIV were calculated under several numerical methods, such as Newmark-β, HPD-L (High Precision Direct integration scheme-Linear form) and HPD-S (High Precision Direct integration scheme-Sinusoidal form), etc.. According to the measured value, the accuracy curves were given to show the best method, which was more stable and accurate than others.2. Furthermore, assuming barrel-shaped mast covered with ice, this paper revealed ice influnces to structural responses of VIV. The increase of ice thickness or the decrease of ice density can enlarge structural responses. The results also supported that the change of structural responses was mainly decided by the front face area. On the other hand, this paper not only studied the vortex-induced force propulsion of the WIG thrusters'foil-shaped wing, but also investigated the VIV of a fixed propeller's foil-shaped blade. The former expressed the advantage from vortex shedding phenomenon of moving structure, and the latter represented the disadvantage from vortex shedding phenomenon of static structure. An advanced fluid-structure interaction approach CLE (Compatible Lagrangian-Eulerian) was adopted into above numerical simulations.1. Based on the comparison of CLE and single Lagrangian, it was confirmed that CLE was more efficient in building model and more proper in describing fluid flow.2. Assuming that different WIG thrusters have different elastic ratios or material types, both hydrodynamic data and structural dynamic responses were showed after the numerical simulations. The thrust force coefficient CT and the propulsive efficientηwere in parabolic distribution under elastic ratio decrease. And, the maximum structural stress reduced along with elastic ratio cutting down. Moreover, the results also agreed that proper organic foil can provide better performance and lower structural stress than steel foil.3. The fluid-blade interaction model was built for studing vortex shedding phenomenon and structural responses of propeller's blade. It displayed the vortex broken positions due to irregular shape of blade. And, the interaction among vortexes decreased the vortex pressure and disordered the whole flow field. Finally, it calculated and showed structural responses of blade different parts.
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