物理学报2016，Vol.65Issue(21)：214701-1-214701-16,16.DOI:10.7498/aps.65.214701
高超临界雷诺数区间内二维圆柱绕流的实测研究∗
Field measurements on flow past a circular cylinder in transcritical Reynolds numb er regime
摘要
Abstract
Flow around a circular cylinder is a classic scenario which invariably draws the attention of the fluid mechanics circle, because its relevant studies are of both theoretical and practical significances. However, most experiments are conducted below transcritical Reynolds number (Re) regime (Re<3.5 × 106) due to the limitations of the wind tunnel modeling technique, which makes the obtained results inapplicable to some full-scale conditions. To this end, the field measurements for wind-induced pressures on a 167-meter high large cooling tower are conducted at Re=6.59 × 107 to enrich the experimental results of flow past a circular cylinder in transcritical Re regime. Besides, the wind effects at low Re (Re=2.1 × 105–4.19 × 105) are also obtained by tests on a 1:200 rigid cooling tower model in a wind tunnel with considering 4 types of wind speeds, 8 types of surface roughness, and 2 flow fields. Employing the data obtained from both field measurements and wind tunnel model tests, the variations of static/dynamic flow characteristics with Re increasing are studied. It is found that 1) with the increase of Re, the drag coefficient for the smooth-walled tower in the uniform flow field decreases dramatically in the critical Re regime and increases slowly in the supercritical regime, which accord with Roshko’s and Achenbach’s results;2) for smooth-walled tower, both the base pressure coefficient and pressure coefficient increase significantly with the increase of Re in critical and supercritical regimes, which qualitatively accord with Shih’s results;and 3) the finding of the Strouhal number is supportive to Shih’s result (i.e., shedding from the rough cylinder persists throughout the Re range tested). More importantly, special attention is paid to the Re-independence phenomenon of fluid flow, which is a typical phenomenon occurring in transcritical Re regime. Results indicate that the Re-independence exists in an Re range from 2 × 105 to 1 × 108 for a circular cylinder with a relative roughness greater than 0.01, and the increased free-stream turbulence can also induce Re-independence which probably exists in a narrow low Re range. Considering the flow mechanism, a reasonable explanation can be found for the Re-independence phenomenon, i.e., the critical and supercritical regimes narrow and move to lower Re range with the increase of surface roughness or the increase of free-stream turbulence, so Re independence can occur at a very low Re.关键词
圆柱绕流/高超临界雷诺数区间/现场实测/雷诺数不相关Key words
flow past a circular cylinder/transcritical Reynolds number regime/field measurement/Reynolds number independence引用本文复制引用
程霄翔,赵林,葛耀君..高超临界雷诺数区间内二维圆柱绕流的实测研究∗[J].物理学报,2016,65(21):214701-1-214701-16,16.基金项目
国家自然科学基金(批准号:51222809,51178353)、科技部重大科技项目(批准号:2009ZX06004-010-HYJY-21)和教育部新世纪优秀人才支持计划资助的课题 （批准号:51222809,51178353）
