Comparative Hydrodynamic Performance Analysis Of Three Typical Kinds Of Semi-submersible Floating Foundation Of Offshore Wind Turbine

With the increasing of environmental pressure and fossil energy depletion is getting worse,clean energy began to occupy an important part of national energy supply component.wind power as a kind of clean energy,is attaching great importance in the countries all over the world,because of it’s no pollution,sustainable development and easy to access.in the wind power industry,the offshore wind power by right of it near the economic center and the abundant reserve,has become the main direction of wind power development.the wind power in offshore area are mainly composed of fixed form foundation,with the increase of water depth,around 40-50 m depth interval,it had arrived at critical depth of fixed and floating foundations,Under the condition of deeper water depth,the floating foundation of wind turbine has better economic and technological advantages.Therefore,the floating wind power will become the main development direction of offshore wind power in the future,which has important engineering significance for the research on the floating foundation of offshore wind turbine.This paper based on three typical semi-submersible floating foundation:OC4,Windfloat,Ideol,By referring to the characteristics of three typical different types of floating foundations,and based on the three-dimensional potential flow theory,the hydrodynamic model is established by AQWA,then the comparative analysis of hydrodynamic performance,the dynamic responses coupled with wind,wave,and current in the time domain under different south china sea circumstances and the adaptability at different water depths were calculated.It took the conclusion that:(1)Through frequency-domain analysis,the surge performance of three-type foundation are similar,the heave response of damping pool foundation in low-frequency range is less than OC4 and Windfloat foundation,and the overall pitch response of Windfloat foundation is smaller than that of OC4 foundation and damping pool foundation.while the pitch response of damping pool foundation is much larger than that of OC4 and Windfloat foundation.(2)Through time domain analysis,the statistical values in surge of the three-type foundation response are similar;the mean and peak values of the OC4 foundation’s heave response are the smallest;the Windfloat’s heave response is much larger than that of the OC4 and damping pool foundation,which means it has poor heave performance,and the meanvalue of the damping pool foundation’s pitch response is the smallest,while the peak value is the biggest,because of the relatively small draught,the pitch performance can be easily influence by the environmental loads。(3)The OC4 foundation has a good adaptability in deep water depth,and the Windfloat foundation has good adaptability in medium water depth.the heave and pitch RAO of damping pool foundation varies not obviously with the increase of water depth and it has a better adaptability in shallow water.(4)Selection suggestion: the heave plate structure of Windfloat foundation is better than that of OC4 foundation’s pontoon in anti-rolling;the skirt-plate structure of damping pool foundation has better heave performance;the damping pool foundation has excellent adaptability in shallow water,but the pitch performance is poor;like the OC4 foundation with large displacement and deep draft has better comprehensive performance,which is the mainstream of development under the background of big power wind turbine.