Linear and quadratic damping coefficients of a single module of a very large floating structure over variable bathymetry:Physical and numerical free-decay experiments  

作　　者：Yiting Wang Ziying Tang Lei Wang Xuefeng Wang 

机构地区：[1]State Key Laboratory of Ocean Engineering,Shanghai Jiao Tong University,Shanghai 200240,China [2]SJTU-Sanya Yazhou Bay Institute of Deepsea Science and Technology,Sanya 572024,China

出　　处：《Journal of Ocean Engineering and Science》2022年第6期607-618,共12页海洋工程与科学（英文）

基　　金：the support of the National Natural Science Foundation of China(Grant No.51979167,51179103);the Ministry of Industry and Information Technology(Grant No.[2018]473);the China Scholarship Council(Grant 201806230206);the Hainan Provincial Joint Project of Sanya Bay Science and Technology City(Grant No.520LH051).

摘　　要：The linearity assumption is widely used when acquiring the hydrodynamic coefficients of a floating structure.However,the linear damping is frequently underestimated,especially for the natural frequency.To investigate the sloping seafloor effects on the damping terms of a single module of a semi-submersible Very Large Floating Structure(VLFS),this paper revisits the conventional formulation and further proposes the direct integration method for obtaining the linear and quadratic damping coefficients from free-decay tests.Numerical free-decay simulations of the single module over variable bathymetry are carried out by the CFD numerical tank.Corresponding model tests are also implemented to verify and validate against the numerical solutions.The effects of the sloping seafloor,as well as the water depth,on the hydrodynamic coefficients are investigated based on the validated CFD modeling.Both numerical and experimental results indicate that the acquisition of the linear and quadratic damping coefficients is sensitive to the data-processing and identification approaches.For the case studied in present paper,the identification errors introduced by the conventional method are 1.5%while they are 0.5%using the direct integration method.The quadratic damping coefficient for heave mode decreases about 10.4%when the sloping angle increases from 0 to 6 deg.

关 键 词：Quadratic damping coefficient Very large floating structure Model tests Numerical simulations 

分 类 号：P75[天文地球—海洋科学]