Reynolds-Number Dependence of Gas Dispersion Over a Wavy Wall
Reynolds-Number Dependence of Gas Dispersion Over a Wavy Wall
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波状壁上气体扩散的雷诺数依赖性
DOI：
10.1007/s10546-017-0261-2
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Sato Ayumu
中科院分区：
文献类型：
--
作者：
Michioka Takenobu;Takimoto Hiroshi;Ono Hiroki;Sato Ayumu
采用大涡模拟研究了波浪壁面上气体弥散的雷诺数依赖关系，因为雷诺数依赖关系对于再现风洞中的正常流动和气体弥散非常重要。波浪表面的振幅与波长之比设为0.1，基于体速度和通道高度的雷诺数变化为。两种示踪气体从位于波壁单一波峰和波谷的点源发射。当雷诺数最低时，经过波浪壁面的气流在波峰后分离，并重新附着在上坡上。在槽附近观察到一个再循环区，从槽排出的气体通过再循环逆流逆风输送。一些气体通过起源于再循环区的间歇性速度爆发从山谷中排出。随着雷诺数的增加，再循环区缩小，流动越来越顺波壁流动。气体一般沿前向分散，由对流排出。从波峰喷出的气体随分离流分散，部分气体在较低雷诺数处被困在再循环区内。随着雷诺数的增加，气体平流越来越跟随波壁，峰值浓度高度接近波壁。此外，两种源谷内的累积浓度在很大程度上取决于雷诺数。
Large-eddy simulation is used to investigate the Reynolds-number dependence of gas dispersion over a wavy wall, because the Reynolds-number dependence is important for reproducing normal flow and gas dispersion in a wind tunnel. The ratio of amplitude to wavelength of the wavy surface is set to 0.1, and the Reynolds number based on the bulk velocity and the channel height is varied fromto. Two tracer gases are emitted from point sources located at a single crest and trough of the wavy wall. For the lowest Reynolds number, the flow over the wavy wall separates behind the crest and reattaches to the upslope. A recirculation zone is observed near the trough, and the gas emitted from the trough is transported upwind by the recirculating reverse flow. Some gas is discharged from the valley by intermittent velocity bursts that originate in the recirculation zone. As the Reynolds number is increased, the recirculation zone shrinks and the flow increasingly follows the wavy wall. The gas generally disperses in the forward direction and is discharged by the advective flow. As for the gas emitted from the crest, this disperses with the separating flow, while some gas is trapped within the recirculation zone at the lower Reynolds number. As the Reynolds number is increased, the gas advection increasingly follows the wavy wall and the height of the peak concentration approaches the wavy wall. In addition, the accumulated concentration within the valley in both sources depends strongly on the Reynolds number.