Suppressing Methods of the Pressure Fluctuation in Open Jet Wind Tunnels

IF 1.3 4区工程技术 Q4 MECHANICS

Journal of Applied Fluid Mechanics Pub Date : 2023-10-01 DOI:10.47176/jafm.16.10.1889

H. Xingjun, L. Yufei, S. Keyuan, †. G.Peng, W. Jingyu

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引用次数: 0

Abstract

Due to the distinctive structure of the test section, the open jet wind tunnel generates low-frequency pressure fluctuations (LFFs) within the range of typical wind speeds. These fluctuations significantly compromise the quality of the flow field in the test section. The evolution of the flow structure and vortex is analysed through the improved delayed detached eddy simulations (IDDES). The LFFs and the control mechanism in the open jet wind tunnel of Jilin University are then studied. The interaction between the large-scale vortex shedding at the nozzle exit and the collector forms the edge feedback, which is the main reason for the pressure fluctuation. According to the feedback mechanism, the LFFs are suppressed using the throat gap and by improving the collector shapes. The results show that the increase of the throat gap length at the collector can significantly alleviate the pressure accumulation inside the collector. The change of the collector shapes can control the impact area and time of the incoming flow, or produce permanent vortex structure to affect the impact shape of the vortex and the flow field at the collector, which allows to control the LFFs. This study lays a solid foundation for further comprehension of the aerodynamic characteristics of the open jet wind tunnels.

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开放式射流风洞压力脉动的抑制方法

由于试验段的独特结构，开放式喷气风洞在典型风速范围内产生低频压力波动（LFF）。这些波动显著地损害了测试段中流场的质量。通过改进的延迟分离涡模拟（IDDES）分析了流动结构和涡流的演变。对吉林大学开放式喷气风洞的LFF及其控制机理进行了研究。喷嘴出口处的大规模旋涡脱落与收集器之间的相互作用形成了边缘反馈，这是压力波动的主要原因。根据反馈机制，使用喉部间隙和通过改进收集器形状来抑制LFF。结果表明，增大集电器喉部间隙长度可以显著缓解集电器内部的压力积聚。收集器形状的变化可以控制流入流的冲击面积和时间，或者产生永久的涡流结构来影响涡流的冲击形状和收集器处的流场，这允许控制LFF。这项研究为进一步理解开放式喷气风洞的气动特性奠定了坚实的基础。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Applied Fluid Mechanics THERMODYNAMICS-MECHANICS

CiteScore

2.00

自引率

20.00%

发文量

138

审稿时长

>12 weeks

期刊介绍： The Journal of Applied Fluid Mechanics (JAFM) is an international, peer-reviewed journal which covers a wide range of theoretical, numerical and experimental aspects in fluid mechanics. The emphasis is on the applications in different engineering fields rather than on pure mathematical or physical aspects in fluid mechanics. Although many high quality journals pertaining to different aspects of fluid mechanics presently exist, research in the field is rapidly escalating. The motivation for this new fluid mechanics journal is driven by the following points: (1) there is a need to have an e-journal accessible to all fluid mechanics researchers, (2) scientists from third- world countries need a venue that does not incur publication costs, (3) quality papers deserve rapid and fast publication through an efficient peer review process, and (4) an outlet is needed for rapid dissemination of fluid mechanics conferences held in Asian countries. Pertaining to this latter point, there presently exist some excellent conferences devoted to the promotion of fluid mechanics in the region such as the Asian Congress of Fluid Mechanics which began in 1980 and nominally takes place in one of the Asian countries every two years. We hope that the proposed journal provides and additional impetus for promoting applied fluids research and associated activities in this continent. The journal is under the umbrella of the Physics Society of Iran with the collaboration of Isfahan University of Technology (IUT) .