Numerical Simulation Of Wave Loads On Single Cylinder In A Steady-state Wave System

With the increasing exhaustion of land energy resources,human beings gradually focus on the oceans,which account for 70% of the earth's surface area.To obtain these ocean resources,marine engineering structures are indispensable.In the design and manufacture of offshore engineering structures,the prediction of environmental loads is an important link.In the ocean,waves are all non-linear,and the equilibrium wave is the basis of studying the evolution of non-linear wave.Therefore,it is of great significance to study the wave loads of structures in the steady-state wave system.Comparing with traditional physical model experiments,computational fluid dynamics(CFD)simulation is became more and more popular among researchers in this field.Among many computational fluid dynamics software,open source CFD soft OpenFOAM is used by more and more people because of its distinct advantages.In this paper,a numerical wave tank based on OpenFOAM is constructed to study the wave loads on a single cylinder in the steady-state wave system.The main contents are as follows:(1)The numerical wave pool constructed by waves2 Foam,a wave-making tool based on OpenFOAM,uses VOF method to track the free surface,and uses ccm26 ToFoam to map Star-CCM+ powerful meshing ability onto the numerical wave pool.(2)The validity of the numerical wave tank is validated by the numerical simulation of a single Stokes wave using the two-dimensional numerical wave tank and the method of comparison between numerical simulation and theoretical value.Then the weak non-linear steady-state wave group is simulated to verify the feasibility and accuracy of the numerical pool in the simulation of the steady-state wave group,and the method is successfully used to simulate the non-linear steady-state wave group.Suggestions for meshing of numerical simulation of regular and steady-state wave groups are also proposed.(3)By establishing a three-dimensional numerical tank,the wave loads on a single cylinder are simulated by a group of linear and non-linear wave groups with the same mass,momentum and energy flux.When linear wave group and non-linear wave group act on the same single cylinder,the trend of wave load changing with time is similar to that of wave height measured at the same pool edge,and the ratio of maximum load to maximum amplitude of wave is close.The larger amplitude and steeper peak make the non-linear wave group climb higher than the linear wave.In this simulation,the maximum amplitude ratio of two groups of waves is 1.45 times,but the maximum liquid height ratio monitored on the front of the cylinder is 2.275 times.On the side of the cylinder,the ratio falls back to 1.984,and behind the cylinder is 1.322.The influence of the cylinder on the free surface of the wave group in the steady-state wave system mainly occurs on the front and side of the wave,but slightly on the back of the cylinder.In this paper,a numerical wave pool is successfully constructed to simulate the steady-state wave group,and some suggestions for meshing the numerical simulation of the steady-state wave group are put forward.On this basis,a group of linear and non-linear wave loads with the same mass,momentum and energy fluxes are compared and analyzed,which is helpful for the numerical simulation of steady-state resonance wave.