Hydrodynamic Performance Analysis Of Cell Spar Type Off-shore Wind Turbine

On the way to further exploit offshore wind energy, conventional fixed bottom technology hasbeen limited by the water depth. Moreover, limited wind speed, visual pollution and large land occupations make onshore wind farms seeing limits to the increasing demands of renewableenergy. For further exploitation, offshore wind energy caught our eyes with higher winds speed and less intense used area, of which is believed to be on the verge of a phase of fast expansion. To achieve this goal, how to investigate new support structures became the top consideration.Differing from drilling platforms, offshore wind turbine requires less buoyancy but better pitch and heave performance due to smaller support weight and considerable moment induced bywinds. Derived from commercialized offshore oil and gas platform of Cell Spar, a conceptualdesign of a Cell Spar type support structure for offshore wind turbine is proposed. For furtherhydrodynamic performance estimations, numerical simulations have been performed to compute the response amplitude operators and the wave response motions, which are the key factors of the preliminary design. The influence of different parameters on the motion performanceCell Spar floating offshore wind turbine were analyzed, Which can be an enlightenment for other researchers.The main contents and results are as follows:Firstly, based on the three-dimensional frequency domain potential flow theory, analysis of the movement characteristics has been carried out. The impact of heave plate number, water depth and height of center of gravityfor hydrodynamic performance of Cell Spar type offshore wind turbine has been studied. Comparison of motion characteristics between Cell Spar and Classic Spar has been carried out,which can be useful for futher studies.Second, On the basis of three-dimensional time-domainpotential flow theory, the motion performance of Cell Spar type offshore wind turbine has been studied. Studies of motion coupling performance between pontoon mooring system and thetraditional system in time domain has been taken. The pontoon mooring system shows betterperformance. The impact of different wave height, wave direction and wind speed has been ta king into consideration. Impact of the chain breaking of the mooring system under extreme sea conditions has also been analyzed.Finally, based on the theory of three dimensional viscousflow numerical wave tank technology and VOF method, A three dimensional numerical wavetank model of wave structure interaction has been carried out. Based on this model, the motion response under regular wave has been simulated. At last the motion performance of Cell Spar type offshore wind turbine has been studied.