Concept Design And Investigation On Motion Performance Of An Innovative Triple-hull-combined FLiDAR Buoy

With the adjustment of energy consumption structure,national governments have increased the policy support and capital investment for the development and utilization of wind energy resources,especially in the development and utilization of offshore wind energy resources.Offshore wind power industry has good prospects for development and gradually to develop in the direction of large scale and far-reaching sea area.But the measurement of offshore wind profile as the basis of the entire offshore wind power project,the conventional meteorological mast technology can not meet the needs of industry development,while FLiDAR(Floating Light Detection And Ranging)buoy systems,the most advanced offshore wind measurement technology,are a flexible and particularly cost-effective alternative to the conventional way,and offers a great potential to assess offshore wind resources.However,the development and application of FLiDAR buoy system is still at the initial stage,and the corresponding research work is not enough,in our country.In addition,the existing foreign solutions,mostly in the traditional buoy hull modified design,there are still shortcomings.Therefore,the development of a new FLiDAR professional buoy system has obvious strategic and economic value for promoting the development of China offshore wind power industry.In this paper,the FLiDAR wind measurement technology,the typical foreign technology solutions and the corresponding key issues were summarized and analyzed.Based on this,considering the environmental characteristics of coastal waters in China,an innovative Triple-Hull-Combined FLiDAR Buoy concept has been presented.The conceptual design,the intact stability analysis,the hydrodynamic and motion response analysis in the frequency domain and time domain of THC FLiDAR buoy system,have been done.The main contents include the following aspects:1.This paper introduces and summarizes the typical FLiDAR buoy system solutions systematacially in the world through the method of information collection and data collation,and expounds meanwhile analyzes the key problems.Considering the applicability of the new FLiDAR buoy in the coastal waters of China,the selection of water depth and sea condition,the selection of the key equipment of the lidar,the design of buoy supply subsystem and the selection of buoy structure are carried out.The conceptual design of THC FLiDAR buoy system has been made,including the buoy structure and technical characteristics,the main design parameters,installation and distribution methods and the integrity of the stability analysis.Finally,the designed buoy system can meet the corresponding technical requirements,and has excellent stability performance.2.Taking the effect of viscous damping into account,the hydrodynamic force and amplitude-frequency motion response of buoy hull are calculated and analyzed by AQWA program,and the short-term forecast analysis in frequency domain is carried out.The results show that the buoy hull exhibits relatively good hydrodynamic characteristics,which is relatively small in response to pitch,roll and heave motion,and the natural frequency can avoid the main energy frequency range of wave.The influence of wave direction angle,water depth and the distance between small floating bodies on buoy frequency response is explored in the frequency domain.It turned out that the variation of the distance between small floating bodies and wave direction angle have a great influence on the RAOs,and the variation of the water depth has little effect on the RAOs.3.The mooring method commonly used in marine data buoys is systematically summarized.Based on this,the motion response of the buoy body under different mooring modes and the mooring cable tension are compared in order to select and analyze mooring method of the THC FLiDAR buoy,and ultimately confirm the use of single-point mooring.4.AQWA procedure was used to make the time domain coupling analysis of the buoy under the states of operating sea conditions and extreme sea conditions,,including the motion response and the mooring line calculation and statistical analysis,and to check and explain the results according to the corresponding industry standards and specifications.The results show that the mooring system has good control of the buoy hull motion response and meets the design requirements.The mooring system of the THC FLiDAR buoy still has a high margin of safety factor even in 50 years of severe sea conditions,which has sufficient safety and strong production capacity.