Hydrodynamic Research And Analysis Of Anchored Test Platform And Its Carrying Tidal Current Turbine

"National Sea Test 1" is an offshore platform serving marine instrument equipment and test.As a common test platform for marine instrument and equipment,the safety and service life of its anchoring system are affected by marine environmental factors such as wind,wave and current.In order to ensure the long-term safe and reliable operation of the offshore platform in harsh marine environment and satisfy the normal operation of the tidal current turbine carried on the platform,the method of theoretical analysis,numerical simulation and physical model is adopted to analyze the "National Sea Test 1" platform,mooring system and tidal current turbine.In the theoretical analysis,the basic hydrodynamic characteristics of the platform in the ocean,such as six degrees of freedom inherent period,attenuation curve,additional mass and radiation damping,are calculated by using the theoretical methods of frequency domain analysis and time domain analysis.The environmental loads on the platform in water are analyzed by using potential flow theory,and the force analysis method of the anchorage system is derived from the catenary model.The analysis of loaded horizontal axis tidal current energy turbine is based on the impeller momentum theory.In the numerical simulation,based on AQWA numerical simulation,the numerical model of the platform and the mooring system are established,the annual average extreme sea state of Weihai are counted,and the hydrodynamic characteristics of the mooring system in two types of "tension" and "slack" are analyzed under different sea conditions life periods,and the different hydrodynamic time curves are obtained.The maximum and average values of each operating condition are counted.In the physical model test,in order to verify the validity and accuracy of numerical simulation,a 1:30 platform physical model was made according to the analysis of wave maker and wind maker capacity,and similar theory in the marine environmental dynamics laboratory.The operating parameters of wave,wind and current in the basin were set up,and the actual extreme operating conditions are scaled to a certain extent according to the similar theory.Through the basin test,the duration data of two mooring system platforms under different operating conditions are obtained.Through the analysis of the numerical model and physical model of the platform,the feasibility of the research method is confirmed,which can be used in the actual marine engineering test.In order to study the safety and reliability of the platform coupled with tidal current turbine,the hydrodynamic analysis of the coupling between tidal current turbine and platform was carried out.Through the analysis of the coupling model,it can be acquire that the movement of the platform is directly affected by the tidal current turbine,and the movement of the platform also affects the power conversion efficiency of the tidal current turbine.Based on the theoretical basis of potential flow,the feasibility of the research method is determined by the verification of numerical simulation method and physical model test,which provides basis for the selection of mooring system of "National Sea Test 1",and provides certain reference basis for coupling motion problems in other marine engineering.