Research On The Motion Simulation Of Floating Structure In Water Body Based On One-Fluid Model

Waves are one of the environmental loads that must be considered for floating offshore structures.The accurate simulation of floating structures in waves is very important for the design of coastal engineering buildings.The study of the interaction between the floating structure and the mooring system can lay a foundation for the study of the dynamic response characteristics of the floating structure in waves,and then provide a reference for the design of the floating structure.If the motion response of floating structure is to be calculated numerically,the wave simulation in digital wave tank is the first prerequisite.In this paper,a multiphase flow solver is used to construct a two-dimensional viscous numerical wave flume based on the one-Fluid equation.In the one-Fluid model,the immersion boundary method(IBM)is used to establish a generalized equation to control the motion of air,water and rigid bodies.Numerical discretization uses fixed Cartesian grid(MAC method)combined with finite volume method to solve the velocity-pressure coupling problem using a stepwise method,level-set method to track the free surface,and rigid Heaviside function to identify the structure.The velocity boundary entrance wavemaking method is used to define the wave velocity and waveform analysis expression at the entrance boundary to generate the incident wave,and the relaxation method is used to eliminate the wave at the end of the calculation area to prevent any wave from being reflected into the test part.In order to verify the reliability of the wave-making and wave-elimination performance of the constructed numerical wave tank,by simulating different types of waves in the constructed two-dimensional viscous numerical wave tank—regular waves and irregular waves,the waves will be in large scale.A comparative analysis of the physical model results performed by the tank and the obtained digital model results verify the accuracy of the model;then,a variety of different factors such as the height of the incident wave,the period of the incident wave,and the floating body under the action of regular waves and irregular waves are discussed.The influence of relative width and relative draft on the dynamic response of floating structure to heave;finally,in the one-fluid multiphase flow solver,based on the statics equation-catenary method,the floating structure mooring system model is established,The physical model test of a single box floating breakwater verifies the accuracy of the mooring system constructed in this paper for solving waves and ocean floating structures.After that,the dynamic response of the marine floating structure under the action of waves and the force of the anchor chain are numerically calculated.