Study On Dynamic Response Characteristics Of Large Diameter Ocean Buoys Under Random Wave Action

Typhoon waves are irregular waves with strong randomness and high energy,and there is currently little research on the interaction between random waves and anchor structures.This article takes a 10m large-diameter buoy as the research object,selects the wave elements during the transit period of Typhoon "Taili" in the Sanmen Bay area of China as the conditions,and conducts a study on the hydrodynamic characteristics of large-diameter buoys under random wave action through a combination of model experiments and numerical simulations.Firstly,model experiments were conducted to analyze the effects of effective wave height and spectral peak elevation factors on the hydrodynamic characteristics of the buoy,such as motion trajectory,roll,and anchor chain tension,through conducting anchor chain length tests and counterweight tests.The quantified hydrodynamic characteristic parameters of the buoy under different wave elements were obtained.Research has shown that:(1)Under random wave conditions,the motion trajectory and force of the buoy exhibit irregular changes.When the anchoring method is determined,the effective wave height has a significant impact on the hydrodynamic characteristics of the buoy.When changing the spectral peak elevation factor,the hydrodynamic parameters of the buoy do not show linear changes.When the spectral peak elevation factor is greater than 3.3,the changes in the hydrodynamic parameters of the buoy are relatively significant.Therefore,large-diameter buoys have good wave following characteristics under wave conditions with small effective wave heights and spectral peak rise factors less than 3.3.The experimental data in this article provides a reference for the motion and force of buoys under such wave effects.(2)When a buoy adopts single point mooring,the anchor chain should not be too short.A certain amount of movement space should be reserved for the buoy,and the buoy should be equipped with a certain counterweight to ensure that the anchor chain is not easily straightened under random wave action,which is conducive to the stability of the buoy.Secondly,a DualSPHysics MoorDyn coupling model was established based on the SPH method.Wave conditions with an effective wave height of 10cm,an effective period of 1.5s,and a spectral peak elevation factor of 3.3 were selected to compare and verify the motion characteristics of the buoy under single point mooring,and the results were in good agreement.The dynamic response characteristics of buoys under random wave action were studied by conducting anchor chain quantity tests and counterweight tests using the DualSPHysics MoorDyn coupling model.Research has shown that:(1)the number of anchor chains and the weight of the buoy are directly proportional to the stability of the buoy,which can effectively fix the position of the buoy;(2)Choosing more than two anchor chains to anchor the buoy is not easy to lose,and the buoy has good stability.On this basis,equipping the buoy with certain counterweights can further improve its survival ability.The research results of this article can provide reference for the safety assessment and stability of 10m large diameter buoys in specific sea areas,and are of great significance for improving the survival ability of large diameter buoys in harsh sea conditions and the accuracy of monitoring data.