| A new type of floating breakwater(FB),water turbine-type FB,with the function of attenuating wave and generating clean energy is proposed in this paper.The main purpose is to provide safe and durable working environment and electric power for people who lives seaside or on the island.Basing on computational fluid dynamics(CFD)technology,hydrodynamic performance of the FB is explored in the numerical tank under the sea conditions of South China Sea.The results are analyzed to explore the best configuration of the designed model.Main contents are as follows:There are mainly two types of mooring styles for FB: pile-restrained and anchor chain-restrained.According to the character of each mooring style,two kinds of water turbine-type FBs are designed.Pipe-restrained water turbine-type FB is combined with rotary generator,oscillating generator and wind driven generator.Anchor chain-restrained water turbine FB is combined with rotary generator.Based on the theory of viscous flow,the numerical wave flume is established and the correctness of it is verified.Wave dissipation theory is applied in the end of the flume to reduce the effect of reflection wave and the volume of fluid(VOF)method is employed to trace the gas-fluid dynamic interface.The flume with and without waves at the initial moment is simulated respectively and compared.The ability of two kinds of FB to attenuate waves and generate electric power is verified by simulation in the numerical flume.For anchor chain-restrained water turbine FB,three degree of freedom is released: surge heave and roll.Besides,the rotator can rotate related to the buoyancy tank.Basing on the settings of numerical flume,the overlapping grid is used to realize the wave interaction with floating structure.The anchor chain is simulated and the interaction between rotator and the buoyancy tank is released by revolute Joint.Conclusion can be drawn from the comparison of the results that both two FBs have the ability to attenuate the incoming waves and the pile-restrained FB has better effect in generating electric power.Pile-restrained FB is selected to explore the best configuration.Basing on the analysis of the results with the model under wave and current load respectively,the blade number of the FB and the angle of blade do have effect on the ability of FB to attenuate waves and generate power.It is found out that three blades FB with the blade angle being 110 degree has the best property.The hydrodynamic performance and the effect of FB are further explored and the tendency of relative variables is revealed with changes of wave parameter,for instance,wave period and wave height.Two ways are given to select the main dimension of the FB.The first is to select the suitable dimension for single-row FB.The influence on the performance of the dimension is provided for the reader to refer.Secondly,smaller double-row FB can also achieve good results.The performances of single-row and double-row FB are given and contrasted in this thesis. |
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