The Barrel of Ilmenau: A large-scale convection experiment to study dust devil-like flow structures.
The Barrel of Ilmenau: A large-scale convection experiment to study dust devil-like flow structures.
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伊尔梅瑙桶：研究尘暴状流动结构的大规模对流实验
DOI：
10.1127/metz/2020/1046
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发表时间：
2021
影响因子：
1.2
通讯作者：
du Puits
中科院分区：
文献类型：
--
作者：
Loesch;du Puits
我们提出了一个实验室控制实验中的大气沙尘暴的数值模拟验证设施。沙尘暴是一种具有垂直轴的大气涡流，由强烈的太阳辐射和由此产生的垂直温度梯度形成。典型沙尘暴的结构是由近地面的径向入流和涡内的垂直向上流动所主导。近年来，人们利用现场观测、现场测量和大涡模拟（LES）对这些涡旋进行了研究。现场试验受到有限的区域和他们的不可预测的行为，而LES的方法不能解决尘暴不够好。在Rayleigh-Bénard对流中，当Rayleigh数至少为Ra= 107时，在直接数值模拟（DNS）中也可能出现类似尘魔的结构，其优点是可以更精确地解析这些结构。为了验证DNS方法并提供测量数据，在与DNS设置具有相似几何形状的大型Rayleigh-Bénard单元内（即Ilmenau桶内）测量气流，瑞利数从Ra= 106到Ra= 1012。为了测量大体积内的流动，使用光学测量方法来获得单个颗粒的轨迹。由于没有适合如此大测量体积的商业系统，我们开发了自己的系统。
We present an experimental facility for the validation of numerical simulations on atmospheric dust devils in a controlled laboratory experiment. Dust devils are atmospheric air vortices with a vertical axis, and are formed by intense solar radiation and the resulting vertical temperature gradient. The structure of a typical dust devil is dominated by a radial inflow near the surface and a vertical upward flow within the vortex. These vortices have been studied in recent years using field observations, in situ measurements, and large-eddy simulation (LES). Field tests suffer from the limited area and their unpredictable behavior, while the LES approach cannot resolve the dust devils well enough. Dust devil-like structures may also occur in direct numerical simulation (DNS) with a Rayleigh number of at least Ra= 107 in Rayleigh–Bénard convection, with the advantage that the structures can be resolved more precisely. In order to validate the DNS approach and provide measurement data, the airflow is measured inside of a large-scale Rayleigh–Bénard cell of similar geometry (ie inside the Barrel of Ilmenau) to the DNS set-up for Rayleigh numbers from Ra= 106 to Ra= 1012. For the measurement of the flow in a large volume, an optical measurement method is used to obtain the trajectories of single particles. Since there are no commercial systems that are suitable for such a large measurement volume, we developed our own system.