Numerical Simulation Of Wave Slamming Of Cylindrical FPSO

With the increasing of China’s comprehensive national strength,China’s energy consumption is also deepening day by day.The resources on land can no longer meet the growing energy demand.China’s development of fossil energy also looks from land to ocean,and gradually turns from shallow sea to deep sea.Under extreme sea conditions,offshore oil production equipment is prone to wave slamming,which seriously affects the safety of personnel and structure.As one of the main reasons for the damage and even overturning of offshore oil production equipment,wave slamming has naturally become a hot issue for practitioners.Therefore,accurate prediction of wave slamming load is an important basis for offshore oil production equipment.This paper mainly studies the wave motion response and slamming load law of cylindrical FPSO(floating production storage and unloading).Based on the CFD method of computational fluid dynamics,this paper uses STAR-CCM+ and CNT-CGCFD Solver(China numerical tank-Cartesian grid computational fluid dynamics,hereinafter referred to as cnt-cgcfd Solver)to create the wave motion response and slamming load prediction models of cylindrical FPSO under long wave conditions.The former is based on the finite volume method,RANS turbulence model is used to realize the prediction function;The latter is based on rectangular grid,uses Les turbulence model and realizes the prediction function by using the idea of stepby-step method.The main work of this paper is as follows:1)Using STAR-CCM+ and CNT-CGCFD Solver,a numerical model which can effectively predict the motion response and slamming load characteristics of cylindrical FPSO under regular wavelength wave conditions and irregular wave conditions is established,which can accurately simulate the motion response and wave slamming load of cylindrical FPSO.2)In the problem of motion characteristics and wave slamming of cylindrical FPSO in regular wave environment,firstly,the convergence of grid size and time step is analyzed by using STAR-CCM+ and CNT-CGCFD Solver for numerical wave making problem and wave test on deck with fixed hull.Then,the numerical simulation of cylindrical FPSO under different wavelengths and wave heights under regular wavelength wave conditions is carried out,and the numerical simulation data of heave,surge,trim attitude and pressure measuring points of cylindrical FPSO are obtained.According to the numerical simulation results,the effects of wavelength and wave height on the motion attitude and wave slamming of cylindrical FPSO are analyzed.Finally,the motion response and slamming load of cylindrical FPSO under different regular wave environments are summarized and analyzed,and finally the empirical formulas for predicting the motion response and slamming load of cylindrical FPSO are fitted.3)In the problem of irregular wave motion response and wave load of cylindrical FPSO,firstly,the same method is used to analyze the convergence of grid and time step for the 100 year sea state.Then,the numerical simulation of cylindrical FPSO under three irregular wave conditions is carried out,and the numerical simulation data of heave,surge,trim attitude and pressure measuring points of cylindrical FPSO are obtained.Finally,according to the results of numerical simulation,the motion attitude of cylindrical FPSO and the maximum and meaningful values of wave slamming load under different sea conditions are counted,so as to analyze the motion response and slamming load law of cylindrical FPSO under irregular wave conditions.4)The flow field characteristics of typical working conditions are analyzed,and the slamming pressure and flow field changes in a single cycle are compared and analyzed.The effects of different wavelengths and wave heights on the motion response and slamming load of cylindrical FPSO are analyzed to provide reference for the design of such ships.