Study On The Influence Of Ocean Current On Sinking In Deep Water Of The Bucket Foundation With Tower And Vanes For Offshore Wind Power

At this stage,with the development of new basic structure of offshore wind power and the large-scale equipment for maritime operations,the scale of global offshore wind power development is expanding and gradually developing into far-reaching waters.The installation of the bucket foundation in deep water,which has installed the tower and vanes,has the characteristics of short construction time and low construction cost.So the installation of the whole machine has broad development prospects.Based on the 6.45 MW wind turbine,the numerical simulation and model test were used to study the influence of ocean current on sinking in deep water of the whole machine with a single-barrel,multi-bin structure.The specific content and results of the study were as follows:Based on the Genie module in SESAM software,the model of the whole machine was built.The influence of ocean current on sinking of the whole machine in deep water was studied in the SIMO module of SESAM software.When the three cables’ length and the cable’s position of the upstream surface were same,the cables of the back flow surface were symmetrically distributed with the cables of the upstream surface,and the hoop was installed on the tower,it was obtained three cables pulling whole machine was more advantageous that four cables pulling whole machine after analyzing those conditions,that is,the cable’s force,acceleration of fan head,roll angle and pitch angle under different cable’s numbers,sinking depths and flow rates.During the sinking process of the bucket foundation with tower and vanes,the cable’s force of the upstream surface increased with the increasing of the flow velocity,and the cable’s force of the backflow surface increased first and then decreased with the increasing of the flow velocity.When the whole machine sank at different depths,the acceleration of fan head,the roll and pitch angle increased with the increasing of the flow rate.Under the same flow rate,the inclination and acceleration of fan head increased with the increasing of the sinking depth.Under the same sinking depth and the same flow rate,the longitudinal acceleration was the largest,the sway acceleration was second and the heave acceleration was the smallest.When the depth of sinking of the whole machine was large,the pitch angle of the fan head was large and there was more than 10° under the action of small flow velocity.In order to reduce the risk of overturning due to excessive tilt during installation of the whole machine,the flow rate should not exceed 0.5m/s,and accordingly,the maximum value of the cable’s force was about 6000 k N.According to the relevant theory of model test,the model of the whole machine with a single-barrel,multi-cabin structure was designed and made.The dynamic characteristics of the whole machine were tested under different sinking depths and flow rates.The effects of flow velocity on three cables,head acceleration,roll and pitch angle were studied.The conclusions that were consistent with the numerical simulation’s results on the whole were obtained,and these research results can provide technical support for sinking of the whole machine in deep water.At the same time,when the water surface didn’t exceed the top cover of the tube skirt,as the flow rate increases,the pitch angle of the fan head was less than 1°,the roll angle was less than 0.6°,and the heave acceleration was less than 0.015 g.