Air flow inside a vertical pipe induced by a free-falling water jet

IF 2.4 3区环境科学与生态学 Q2 ENGINEERING, CIVIL

Journal of Hydro-environment Research Pub Date : 2022-09-01 DOI:10.1016/j.jher.2022.07.003

Yiyi Ma , Pengcheng Li , David Z. Zhu , Abdul Khan

{"title":"Air flow inside a vertical pipe induced by a free-falling water jet","authors":"Yiyi Ma , Pengcheng Li , David Z. Zhu , Abdul Khan","doi":"10.1016/j.jher.2022.07.003","DOIUrl":null,"url":null,"abstract":"<div><p>The air flow induced by a water jet freely falling inside a vertical pipe with its top and bottom both open to the atmosphere was investigated experimentally and numerically. In the experiments, the radial air velocity distribution and the air pressure variation along the vertical pipe were measured. The air drag of the falling water jet was related to the jet surface disturbance and analyzed by introducing the equivalent friction factor. A predictive model was developed for the air flow inside a 3-m-high pipe based on the momentum equation and its results compared well with the experimental measurements. Numerical simulations were also conducted by approximating the free-falling water jet as a continuous moving solid with diameter and velocity varying in the direction of motion. The effects of pipe size on the air velocity profile and the induced air flow rate were examined. The simulation results showed that the streamwise air velocity profiles inside pipes of different sizes approached the same after a certain traveling distance. The maximum induced air flow rate was found at the pipe diameter of about 20 times of initial water jet diameter.</p></div>","PeriodicalId":49303,"journal":{"name":"Journal of Hydro-environment Research","volume":"44 ","pages":"Pages 23-34"},"PeriodicalIF":2.4000,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Hydro-environment Research","FirstCategoryId":"93","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1570644322000430","RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENGINEERING, CIVIL","Score":null,"Total":0}

引用次数: 0

Abstract

The air flow induced by a water jet freely falling inside a vertical pipe with its top and bottom both open to the atmosphere was investigated experimentally and numerically. In the experiments, the radial air velocity distribution and the air pressure variation along the vertical pipe were measured. The air drag of the falling water jet was related to the jet surface disturbance and analyzed by introducing the equivalent friction factor. A predictive model was developed for the air flow inside a 3-m-high pipe based on the momentum equation and its results compared well with the experimental measurements. Numerical simulations were also conducted by approximating the free-falling water jet as a continuous moving solid with diameter and velocity varying in the direction of motion. The effects of pipe size on the air velocity profile and the induced air flow rate were examined. The simulation results showed that the streamwise air velocity profiles inside pipes of different sizes approached the same after a certain traveling distance. The maximum induced air flow rate was found at the pipe diameter of about 20 times of initial water jet diameter.

查看原文本刊更多论文

自由下落水射流诱导垂直管道内的气流

用实验和数值方法研究了水射流在上下都对大气开放的垂直管道内自由落体所引起的气流。在实验中，测量了沿垂直管道的径向风速分布和气压变化。通过引入等效摩擦系数，分析了水射流的空气阻力与射流表面扰动的关系。基于动量方程建立了3 m高管道内气流的预测模型，其结果与实验测量结果吻合较好。将自由落体水射流近似为直径和速度随运动方向变化的连续运动固体，进行了数值模拟。研究了管道尺寸对气流速度分布和诱导气流流量的影响。模拟结果表明，不同尺寸的管道在经过一定距离后，其流向气流速度分布趋于一致。当管道直径约为初始水射流直径的20倍时，诱导空气流量最大。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

Journal of Hydro-environment Research ENGINEERING, CIVIL-ENVIRONMENTAL SCIENCES

CiteScore

5.80

自引率

0.00%

发文量

审稿时长

98 days

期刊介绍： The journal aims to provide an international platform for the dissemination of research and engineering applications related to water and hydraulic problems in the Asia-Pacific region. The journal provides a wide distribution at affordable subscription rate, as well as a rapid reviewing and publication time. The journal particularly encourages papers from young researchers. Papers that require extensive language editing, qualify for editorial assistance with American Journal Experts, a Language Editing Company that Elsevier recommends. Authors submitting to this journal are entitled to a 10% discount.