农业机械学报 Pub Date : 2016-01-01 DOI: 10.6041/J.ISSN.1000-1298.2016.02.005

M. Yang, L. Yan, Yuli Wang, C. Gong, J. Lu

{"title":"Instability and interfacial coherent structure of free round turbulent jet","authors":"M. Yang, L. Yan, Yuli Wang, C. Gong, J. Lu","doi":"10.6041/J.ISSN.1000-1298.2016.02.005","DOIUrl":"https://doi.org/10.6041/J.ISSN.1000-1298.2016.02.005","url":null,"abstract":"As a basic flow form, free round turbulent jet has been used in various industry fields such as water jet cutting, water cleaning, fuel spray, etc. To understand the development of jet and some of its underlying characteristics, it is crucial that the mechanism of jet instability should be recognized. A robust two-phase flow large eddy simulation (LES) algorithm was applied to predict the liquid instability and the coherent structure of free round turbulent jet. The main objective was to characterize the liquid instability mechanism without resorting stability analysis. Special attention was focused on how the instability and the eddy structure in the near field of round jet were affected by the imposed inlet velocity and disturbance. In this respect, the cases within the range of Re=10000~80000 at various disturbance intensities were tested. Results revealed that the velocity and disturbances played an important role in the stability of liquid jet. The unperturbed liquid core length and scale of surface wave were decreased, and a wide variety of vortexes were produced in the near field of jet with velocity and disturbance intensity increased. The decay rates of average velocity along the central axis of jet were similar under different disturbance intensities at the same Reynolds number (or different Reynolds numbers at the same disturbance intensity). The positive entrainment was enhanced and the radial spread of the jet along the streamwise became more significant with the Reynolds number increased.","PeriodicalId":35080,"journal":{"name":"农业机械学报","volume":"39 1","pages":"35-44"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86179912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Forward kinematics of 3-PPR parallel mechanism based on improved ant colony algorithm 基于改进蚁群算法的3-PPR并联机构正运动学

农业机械学报 Pub Date : 2015-07-25 DOI: 10.6041/J.ISSN.1000-1298.2015.07.048

Xiaoyong Wu, Zhijiang Xie, Daiping Song, Fei Liu, Jiufei Luo, Bingyan Mao

引用次数: 3

Locust remote sensing monitoring methods based on landsat8 satellite data 基于landsat8卫星数据的蝗虫遥感监测方法

农业机械学报 Pub Date : 2015-05-25 DOI: 10.6041/J.ISSN.1000-1298.2015.05.037

Jianxi Huang, Wen Zhuo, Chun-Gui Yang, Lin Li, Chaomang Zhang, Jia Liu

引用次数: 3

Mobile GIS based approach for collection of crop planting environment data 基于移动GIS的农作物种植环境数据采集方法

农业机械学报 Pub Date : 2015-01-01 DOI: 10.6041/J.ISSN.1000-1298.2015.09.048

Sijing Ye, Dehai Zhu, X. Yao, Yan-Li Yue, Jianxi Huang, Lin Li

引用次数: 2

Pressure fluctuations around volute tongue of centrifugal pump 离心泵蜗壳隔舌周围压力波动

农业机械学报 Pub Date : 2015-01-01 DOI: 10.6041/J.ISSN.1000-1298.2015.06.014

J. Cai, J. Pan, A. Guzzomi

引用次数: 2

Dynamic analysis of decoupled spherical parallel mechanism for vectored thruster 矢量推进器解耦球面并联机构动力学分析

农业机械学报 Pub Date : 2015-01-01 DOI: 10.6041/J.ISSN.1000-1298.2015.06.046

Rongmin Zhang, Lt, strong gt, Yuan Chen, Jundong Gao

引用次数: 2

Internal flow characteristic of screw centrifugal pump based on PIV 基于PIV的螺杆泵内部流动特性研究

农业机械学报 Pub Date : 2015-01-01 DOI: 10.6041/J.ISSN.1000-1298.2015.04.005

H. Quan, Ren-nian Li, Q. Su, W. Han, Lei Jiang, Yi Jin

引用次数: 0

Estimating stand volume of Xylosma racemosum forest based on texture parameters and derivative texture indices of ALOS imagery 基于ALOS影像纹理参数和衍生纹理指数估算总状木林林分积

农业机械学报 Pub Date : 2014-01-01 DOI: 10.6041/J.ISSN.1000-1298.2014.07.038

J. Liu, H. Bi, P. Zhu, Jingmei Sun, J. Zhu, T. Chen

{"title":"Estimating stand volume of Xylosma racemosum forest based on texture parameters and derivative texture indices of ALOS imagery","authors":"J. Liu, H. Bi, P. Zhu, Jingmei Sun, J. Zhu, T. Chen","doi":"10.6041/J.ISSN.1000-1298.2014.07.038","DOIUrl":"https://doi.org/10.6041/J.ISSN.1000-1298.2014.07.038","url":null,"abstract":"The Xylosma racemosum forest located in Huairou District of Beijing was chosen as research objects, texture parameters as well as derivative texture indices of different window sizes from ALOS fusion imagery with resolution of 2.5 m were measured. Stepwise multiple regression models were developed to describe the relationship between textures (including texture parameters and derivative texture indices) and field measurements of stand volume. The main objective was to compare estimation accuracy between model established by texture parameters and that by derivative texture indices, select the most effective Xylosma racemosum stand volume estimate model and select the most effective window size. Results indicate that the value of adjusted R2 of fitting models established by derivative texture indices were better than those of texture parameters at the same window size, the value of adjusted R2 of stand volume model could be improved significantly by combination of texture parameters and derivative texture indices at the same window size, the optimal estimation model of Xylosma racemosum stand volume was obtained when all of the texture parameters and derivative texture indices of all window sizes were introduced into stepwise multiple regression, 11×11 was the optimal window size with the largest adjusted R2 for fitting Xylosma racemosum stand volume by texture parameters and derivative texture indices generated at one single window size.","PeriodicalId":35080,"journal":{"name":"农业机械学报","volume":"52 1","pages":"245-254"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80823620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Simulation of Bio-syngas Production from Biomass Gasification via Pressurized Interconnected Fluidized Beds 加压互联流化床生物质气化生产生物合成气的模拟

农业机械学报 Pub Date : 2014-01-01 DOI: 10.1007/978-3-642-37922-2_122

Fei Feng, G. Song, Laihong Shen, J. Xiao

引用次数: 8

Analysis of eddy viscosity models in predicting flow field of high-speed water jet 涡流黏度模型在高速水射流流场预测中的应用分析

农业机械学报 Pub Date : 2014-01-01 DOI: 10.6041/J.ISSN.1000-1298.2014.07.047

M. Yang, J. Lu, Yuli Wang, C. Gong, L. Yan

引用次数: 0

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