Investigation Of The Structural Dynamic Response For Vertical-Axis Tidal Curret Turbine

The investigation of the structural dynamic response for tidal current turbine has received a lot of attention in the society.Many numerical and experimental investigations have been conducted to study the tidal current turbine characteristics.These studies focus on the hydrodynamics or power output of the tidal turbine.The structural dynamic response of tidal current turbine is also very important considering the material makeup and stability and reliability of the turbine.This thesis presents three-dimensional numerical analysis on the blade response of the vertical-axis tidal turbine based on discrete vortex method(Discrete vortex method—DVM-UBC)and beam solver(Geometrically Exact Beam Theory—GEBT).It is the first time to use the beam solver(GEBT)to perform the dynamic analysis for tidal current turbine.Comparing with the traditional three dimensional finite element method,the new method has a lot of advantages,such as saving computing cost,easily building model and high accuracy and so on.In the modal analysis,the nature frequency of single blade and entirely turbine with various H/R ratio are obtianed and we find that the size of arms have bigger influence on the frequency than that of blade.In the transient dynamic analysis,the deflections of blade tip in one complete rotation with various H/R ratios is investigated.Compared results with the critical deflections,we find that when the height-to-radius(H/R)is greater than 3.0,the maximum deflection is greater than the critical deflection that leads to turbine failure.At last,this paper used variational asymptotic beam section analysis method(VABS)to get the stress component distribution contour with various H/R ratio.The structural dynamic response of tidal current turbine based on GEBT method can provide a new insight and method for designer.The conclusion of this paper have great reference value.