Numerical Simulation Of Flow Around A Four Cylinders In A Square Arrangement And Analysis Of Its Influencing Factors

The flow around a cylinder has always been a classical problem in the study of fluid mechanics,and the application of the theory of the flow around a cylinder will also be involved in engineering practice,so the research on the flow around a cylinder has always been a hot spot.With the development of industrial technology and people's great demand for energy,oil and gas resources on land are increasingly exhausted,and the demand for exploitation of offshore oil resources is becoming more and more urgent.Therefore,the safety of offshore operation platforms has begun to be concerned by researchers.In the process of offshore oil exploitation,a large number of cylinder groups with different diameters will be applied,but at present,there are relatively few studies on the flow around cylinders with different diameters.Therefore,this paper mainly studies the four equal diameters based on practical problems.Wake characteristics of flow around a cylinder and four cylinders of unequal diameter and force characteristics on the surface of each cylinderFirstly,this paper introduces the research status of the flow around the cylinder at home and abroad,and then simulates the mesh division and calculation method by the single cylinder flow and the series parallel double cylinder flow.The verification results show that the network of this paper The division and calculation method is correct.Next,numerical simulations of flow around four square cylinders of equal diameter with different spacing ratios(L/D=1.5,2,2.5,3,3.5,4)are carried out.The simulation results mainly include the vorticity distribution of wake flow field,the streamline of wake flow field,lift-drag coefficient,Stroha number and so on.Based on the simulation results and the data obtained from the simulation,the influence of the spacing on the flow around four cylinders is analyzed.Aiming at the flow around four cylinders with different diameter ratios(d/D=d/D=0.2,0.4,0.6,0.8,1.0 and 1.2),the flow around four cylinders with different diameter ratios is simulated in this paper.Streamline,lift-drag coefficient and Stroha number are used to analyze the influence of diameter variation on flow around four cylinders with different diameters.By simulating the flow around four cylinders arranged in square arrays with different spacing ratios and four cylinders with different diameter ratios,the effects of spacing and diameter on the wake flow pattern and the forces acting on the surface of the four cylinders arranged in square arrays are preliminarily revealed,which provides a theoretical study for solving practical engineering problems in the future.