Numerical Investigation To The Interaction Of Multi-directional Irregular Wave And An Array Of Cylinders

As the process of developing marine resources is accelerated,many large-scale offshore structures arises at the right moment.The large scale cylinders as the basic structures are often used in cross-sea bridge,offshore marine platforms and so on.Therefore accurate calculation of wave interaction with the large-scale cylinders has the vital significance to actual engineering design.The paper adopts the method of numerical calculation,based on the linear theory of wave refraction combined with simulation of multi-directional irregular wave,a method to calculate multi-directional irregular wave loads on a array of large diameter cylinders is established by superposition method.The layout of cylinders in existing research generally is tandem or parallel.Aimed at the condition that the research of complex array comprised of large quantity of cylinders with multidirectional wave is absent,three kinds of representative layout of cylinders are considered in this paper.The result of wave height and wave force is calculated and the effect caused by wave directionality,distances between cylinders and different positions on wave run-up and wave force are analyzed.The results show that the front cylinders has a blocking effect on its rear one in the arrays.It is obvious that the distribution pattern of wave run-up along the surface and the variation of wave run-up with wave directionality are affected by the distance between cylinders.When the cylinders are close,there is a phenomenon that the wave run-up is obviously higher which produce maximum wave run-up affected by the interaction between cylinders.When the cylinders are far,the wave run-ups on different cylinders are the same,and the maximum wave run-up is at the front point of the cylinder.The wave force is also affected by the wave directionality.The basic change trend is that the wider the wave directional distribution is,the smaller the normal wave force is,and the significant increase of the transverse wave force at the same time.What is noteworthy is that the normal force does not always conform to the aforementioned law because the interaction of multi-directional wave and cylinders is complicated when directional spreading is very small.The wave force characteristics of different cylinders are obviously influenced by the distance and arrangement form.In addition,the group coefficient of cylinders in different layouts is given,which will provide a reference for practical engineering design.Because the number of cylinders is large and the multidirectional wave impact is complex,the influence of group is not completely eliminated when the distance between cylinders is fairly large.