| 摘要: |
| 后台阶流是几何结构简单而流态复杂的流动现象.采用二维k-ε紊流模型对后台阶水流流动进行数值模拟，并结合PIV系统测得的雷诺数，对Re=500~50 000范围的台阶后定常流动流场数据进行对比分析研究.结果表明流场结构存在稳定的回流区，回流区长度随着Re的增大先急速上升，然后又急速下降，最后缓慢回升直至稳定.断面速度受回流区影响较大，峰值随断面的往下游推移逐渐减小，随Re的增加，断面速度也缓慢减小.压力、紊动能的分布也受到回流区的影响，其中紊动能在低雷诺数情况下受回流区的影响较小. |
| 关键词: PIV 后台阶流 k-ε紊流模型 雷诺数 |
| DOI： |
| 分类号:TV 135 |
| 基金项目:国家水体污染控制与治理科技重大专项项目（2012ZX07506-003-04）；科技部农业科技成果转化资金项目（2011GB23320010）；中央级公益性科研院所基本科研业务费专项（Y112008，Y112005） |
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| Hydraulic characteristics of backward-facing step flow based on k-ε turbulence model |
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XIAO Xiao1, FAN Xin-jian2, WU Shi-qiang2
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1.Nanjing Hydraulic Research Institute;2.State Key Laboratory of Hydraulic Engineering Simulation and Safety， Tianjin University
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| Abstract: |
| The backward-facing step flow is a simple structure but has complex flow patterns. In this paper， the backward-facing step flow is simulated by a 2D k-ε turbulence model. And based on the test results measured by PIV system， we analyzed the flow field data of the backward facing step for Reynold number from 500 to 50，000. The research results show that the flow field structure has a steady recirculation zone， and that the length of the recirculation zone increases rapidly with the increace of Re in the front， then rapidly declines， and finally slowly rebounds and becomes stable. The cross section velocity is affected greatly by the recirculation zone， and the peak value decreases slowly with the increase of Re. The pressure and turbulence kinetic energy are also affected by the recirculation zone， but the turbulence kinetic energy is less affected in low Reynolds. |
| Key words: PIV backward-facing step flow k-ε turbulence model Reynold number |
