Analysis Of Fluid-structure Coupling Characteristics Of Inclined Rotating Multi-cylinder Structure

Under turbulent conditions,the flow around a cylinder has practical significance in various industrial applications,especially in the fields of wind and ocean engineering.Therefore,understanding and controlling these wakes has extremely important scientific and engineering significance.Based on the Fluent software,this paper adopts the large eddy simulation method to carry out a numerical study on the flow field control of the rotating inclined multi-cylinder structure group under Re=3900,and focuses on the analysis of the rotating inclined single cylinder and the rotating inclined tandem double The fluid-solid coupling mechanism of the flow around the cylindrical structure group and the four-cylinder structure group arranged in the rotating oblique square.The main research work of this paper is as follows:(1)Study the flow around a rotating inclined single cylinder structure under the Reynolds number Re=3900,and mainly analyze the influence of the two key parameters of inclination angle and rotation rate on the flow characteristics and mechanical properties of the single cylinder structure.The study found that when the inclined cylinder is at rest,axial flow appears behind the cylinder,and when the inclined cylinder starts to rotate,the axial flow is weakened.At the same time,as the rotation speed of the cylinder increases,the greater the tilt angle of the cylinder,the faster the axial flow disappears.In addition,the principle of independence of the average value of the drag coefficient of a rotating inclined single cylinder has been verified to be applicable within a certain range of inclination angle and speed.(2)Under the Reynolds number Re=3900 working condition,the flow problem of the rotating inclined tandem double-cylinder structure group is studied.The three key parameters of the pitch ratio,the inclination angle and the rotation rate are mainly analyzed for the rotation of the tandem double-cylinder structure group.The influence of flow characteristics and mechanical characteristics,and the mutual interference effect and mechanical mechanism of the tandem double-cylinder structure group are explained.The study found that the changes in tilt angle,pitch ratio and rotation rate have significant effects on the flow characteristics and mechanical properties of the tandem double-cylinder structure group.As the column spacing ratio increases,the axial flow strength is gradually weakened.When the cylinder rotates,the fluid force coefficient of the upstream inclined cylinder shows a decreasing trend,while the average drag coefficient and the root mean square value of the lift coefficient of the downstream inclined cylinder show an increasing trend,the average lift coefficient and the root mean square drag coefficient The value tends to decrease.At the same time,the change of the pitch ratio has a significant effect on the value of the fluid force coefficient of the inclined cylinder.During the rotation of the inclined double cylinder,the proportion of viscous resistance in the fluid resistance is basically higher than that of the differential pressure resistance,and the viscous resistance plays a dominant role.(3)Study the flow around four-cylinder structure group under the condition of Reynolds number Re=3900,mainly analyze the three key parameters of spacing ratio,inclination angle and rotation rate on the flow around the four-cylinder structure group The influence of characteristics and mechanical characteristics,and expounds the mutual interference effect and mechanical mechanism of the four-cylinder structure group.The study found that the changes in tilt angle,pitch ratio and rotation rate have significant effects on the flow characteristics and mechanical properties of the four-cylinder structure group.Under the condition of small inclination angle ?=30°,eddy currents are generated behind the inclined cylinder,and under the condition of large inclination angle ?=60°,there is no vortex shedding behind the cylinder due to the influence of strong axial flow.In addition,as the rotation speed of the inclined cylinder increases,the vortex shedding gradually disappears,and as the tilt angle increases,the axial flow intensity increases.At the same time,the spacing ratio has a significant effect on the shedding of the inclined cylindrical vortex.Under the same inclination angle,with the increase of the rotating speed of the inclined cylinder,the large-scale vortex structure gradually ruptured and reorganized into a small-scale vortex structure.At the same time,due to the increase in the spacing ratio,the eddy current between the inclined cylinders develops more fully,and the vortex structure also increases.It is worth noting that,compared with the small inclination angle,the vortex structure produced under the large inclination angle no longer presents an obvious three-dimensional effect.At the same time,as the rotation speed of the inclined cylinder increases,the average drag coefficient shows an increasing trend,while the average lift coefficient shows a decreasing trend.