基于动网格的铁路沿线孔板式沙障流固耦合数值模拟
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摘要
孔板式沙障是新型多孔的阻风沙构筑物,具有很好的阻风沙功效,但孔板式沙障的应用必须考虑其在风荷载作用下的流场特征以及力学特性。对孔板式沙障进行三维流固耦合数值模拟,分析其在固定孔隙率不变的情况下,孔径变化时沙障周围流场特性以及孔隙率不变孔径变化对沙障位移、应力特征的影响,并总结相关规律特征。研究结果和结论:不同孔径沙障在障后均无涡流区仅有大面积减速区,且减速区随孔径减小而增大,减速效果也随之增强;孔径的变化对沙障的受力特征和变形位移分布无影响,仅对其量值有影响;沙障立柱受力最大位置在距柱底(4.5±0.025)cm,且孔径越小其最大值越大;来流首次接触沙障时会产生"冲击效应",其"冲击效应"最大值为沙障变形的最大值即最危险值,孔径越小,其"冲击效应"最大值越大,稳定状态下的位移值也越大。
The hole-plate sand barrier is a new porous and fence structure with very good effect on wind-sand resistance,but the flow field characteristics and mechanical characteristics of the hole-plate sand barrier under the wind load must be taken into account in its application.Fluid solid coupling numerical simulation of hole-plate sand barrier is conducted to analyze the influence of the characteristics of flow field around the sand barrier with the changes of pore size when the fixed porosity is constant on the displacement and stress of the sand barrier,and when the porosity is constant and the pore size changes.The relevant laws and characteristics are summarized.Research results conclude that there is no eddy zone after the sand barrier with different pore sizes,the deceleration zone increases with the decrease of the pore size and the deceleration effect is thus enhanced; the change of the pore size has no effect on the stress and deformation displacement distribution of the sand barrier,but has effect only on the value; the maximum force position of sand barrier pillar is 4.5 cm away from the bottom of the pillar and the smaller the aperture,the greater the maximum value; when wind first contacts with the sand barrier it generates "impact effect",and the maximum value of "impact effect"is the maximum value of sand barrier deformation and also the most dangerous value; the smaller the aperture,the greater the maximum value of the"impact effect",and also the larger the displacement value in the steady state.
The hole-plate sand barrier is a new porous and fence structure with very good effect on wind-sand resistance,but the flow field characteristics and mechanical characteristics of the hole-plate sand barrier under the wind load must be taken into account in its application.Fluid solid coupling numerical simulation of hole-plate sand barrier is conducted to analyze the influence of the characteristics of flow field around the sand barrier with the changes of pore size when the fixed porosity is constant on the displacement and stress of the sand barrier,and when the porosity is constant and the pore size changes.The relevant laws and characteristics are summarized.Research results conclude that there is no eddy zone after the sand barrier with different pore sizes,the deceleration zone increases with the decrease of the pore size and the deceleration effect is thus enhanced; the change of the pore size has no effect on the stress and deformation displacement distribution of the sand barrier,but has effect only on the value; the maximum force position of sand barrier pillar is 4.5 cm away from the bottom of the pillar and the smaller the aperture,the greater the maximum value; when wind first contacts with the sand barrier it generates "impact effect",and the maximum value of "impact effect"is the maximum value of sand barrier deformation and also the most dangerous value; the smaller the aperture,the greater the maximum value of the"impact effect",and also the larger the displacement value in the steady state.
引文
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[2]Cheng J,Lei J,Li S,et al.Disturbance of the inclined inserting-type sand fence to wind-sand flow fields and its sand control characteristics[J].Aeolian Research,2016,21:139-150.
[3]Cheng,J.J.,Xue,C.X.The sand-damage-prevention engineering system for the railway in the desert region of the Qinghai-Tibet plateau[J].Journal of Wind Engineering&Industrial Aerodynamics,2014,125:30-37.
[4]徐枫.结构流固耦合振动与流动控制的数值模拟[D].哈尔滨:哈尔滨工业大学,2009.
[5]李树云,谭志洪,姜洋,等.基于流固耦合的滤袋振动的数值模拟[J].环境工程学报,2016,10(5):2535-2540.
[6]Paik K J,Carrica P M.Fluid-structure interaction for an elastic structure interacting with free surface in a rolling tank[J].Ocean Engineering,2014,84(7):201-212.
[7]Jaiman R,Geubelle P,Loth E,et al.Combined interface boundary condition method for unsteady fluid-structure interaction[J].Computer Methods in Applied Mechanics and Engineering,2011,200(1-4):27-39.
[8]闫清东,刘博深,魏巍.基于动网格的冲焊型液力变矩器流固耦合分析[J].华中科技大学学报(自然科学版),2015,43(12):37-41.
[9]Stein K,Tezduyar T E,Benncy R.Mesh moving techniques for fluid-structure interactions with large displacements[J].Auris Nasus Larynx,2003,70(1):58-63.
[10]Stein K,Tezduyar T E,Benncy R.Automatic mesh update with the solid-extension mesh moving technique[J].Computer Methods in Applied Mechanics and Engineering,2004,193(21):2019-2032.
[11]Pei J,Yuan S,Yuan J,et al.The influence of the flow rate on periodic flow unsteadiness behaviors in a sewage centrifugal pump[J].Journal of Hydrodynamics,2013,25(5):702-709.
[12]程建军,庞巧东.戈壁强风区挡风构筑物限制下列车气动力学特性分析[J].铁道标准设计,2013,57(1):1-4.
[13]辛国伟,程建军,景文宏,等.来流廓线对风沙流场和风沙堆积影响的数值模拟—以挡沙墙为例[J].干旱区研究,2016,33(3):672-679.
[14]辛国伟,程建军,王连,等.铁路沿线地表条件与风沙流场的互馈规律研究[J].铁道标准设计,2016,60(9):22-27.