Journal of Fluids Engineering最新文献_第10页

Model Verification and Experimental Study of The Turbomachinery Wake Flow Field Reconstruction 涡轮机械拂翼流场重构的模型验证与实验研究

Journal of Fluids Engineering Pub Date : 2023-11-20 DOI: 10.1115/1.4064104

Hanting Gao, Xu Dong, Ruize Xu, Lei Gao, Dakun Sun, Xiaofeng Sun

{"title":"Model Verification and Experimental Study of The Turbomachinery Wake Flow Field Reconstruction","authors":"Hanting Gao, Xu Dong, Ruize Xu, Lei Gao, Dakun Sun, Xiaofeng Sun","doi":"10.1115/1.4064104","DOIUrl":"https://doi.org/10.1115/1.4064104","url":null,"abstract":"A clear understanding of the turbomachinery wake flow field is one of the key problems in developing turbomachinery aerodynamics. The theoretical model of helical vortices is established in cylindrical coordinates (r,θ,z), and the model corresponds to the experimental scheme, which verifies the feasibility of reconstructing flow field by interpolation in r-z plane under different θ. This model shows that theta should not exceed 20 degrees in order to reconstruct the flow field more accurately. Taking rotors as the representative of the turbomachinery, Particle image velocimetry (PIV) is used to measure the velocity field in the rotor wake. Interpolating reconstruction of spacing between different measurement planes, the reconstruction results are relative to the theory, which plane spacing should be less than 20 deg. Using the vorticity weighted average method to calculate the central position of the vortex core, the wandering motion of the tip vortex is obtained. On this basis, a correct conditional average algorithm is proposed to eliminate this effect. Through the analysis method of the circulation, it is proved that the point where the second derivative of the circulation with respect to the radius is 0 corresponds to the radius of the vortex core, and the evolution law of the growth of the vortex core radius is proportional to the square root of the vortex ages. The results provide a reliable experimental method for the quantitative study of the spatio-temporal evolution of complex vortex structures in the three-dimensional flow of turbomachinery wakes.","PeriodicalId":504378,"journal":{"name":"Journal of Fluids Engineering","volume":"37 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139256179","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: 0

Localized Blowing for Near-Wake Flow and Vortical Structure Control in Turbulent Boundary Layers Over Periodic 2D Roughness 在周期性二维粗糙度上的湍流边界层中进行局部吹风以控制近平流和涡旋结构

Journal of Fluids Engineering Pub Date : 2023-11-20 DOI: 10.1115/1.4064103

Ali M. Hamed, Ryan Gallary, Bailey McAtee

{"title":"Localized Blowing for Near-Wake Flow and Vortical Structure Control in Turbulent Boundary Layers Over Periodic 2D Roughness","authors":"Ali M. Hamed, Ryan Gallary, Bailey McAtee","doi":"10.1115/1.4064103","DOIUrl":"https://doi.org/10.1115/1.4064103","url":null,"abstract":"Volumetric three-component flow measurements were made to investigate localized blowing (injection) as a control strategy for turbulent boundary layers over k-type 2D roughness. The flow measurements were made using particle tracking velocimetry at a Reynolds number of 100,000. The roughness occupied ~ 13% of the boundary layer thickness and consisted of transverse square bars positioned periodically at a pitch to height ratio of 11. Two cases were considered: a baseline case without blowing and a case with blowing through five spanwise jets issuing from the downstream face of the 11th bar. The results highlight the effectiveness of blowing in reducing the size of the recirculation zone and turbulence past the bar. Specifically, the spanwise-averaged flow field for the blowing case shows a 40% reduction in the reattachment length and ~ 25% reduction in the maximum Reynolds shear stress relative to the baseline case. Moreover, visualizations of the vortical structures past the bars for the baseline case display coherent spanwise vortices similar to those observed past isolated 2D bars and backward-facing steps. Blowing disrupts these spanwise vortices and produces new weaker vortical structures with a wall-normal sense of rotation. As such, blowing results in a reduction in the spanwise-averaged spanwise vorticity characteristic of the flow over k-type 2D roughness. The disruption of the spanwise vortices and the reduction in the size of the recirculation zone are likely responsible for the reduction in the Reynolds shear stress and turbulent kinetic energy in the near wake.","PeriodicalId":504378,"journal":{"name":"Journal of Fluids Engineering","volume":"129 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139259211","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: 0

Instability of Poiseuille Flow in a Bidisperse Porous Medium Subject to a Uniform Vertical Throughflow Effect 双分散多孔介质中受均匀垂直贯流效应影响的波塞流的不稳定性

Journal of Fluids Engineering Pub Date : 2023-11-20 DOI: 10.1115/1.4064102

Shahizlan Shakir Hajool, A. Harfash

引用次数: 0

X-Ray Flow Visualization: Techniques and Applications X 射线流动可视化：技术与应用

Journal of Fluids Engineering Pub Date : 2023-11-16 DOI: 10.1115/1.4064050

T. Heindel

{"title":"X-Ray Flow Visualization: Techniques and Applications","authors":"T. Heindel","doi":"10.1115/1.4064050","DOIUrl":"https://doi.org/10.1115/1.4064050","url":null,"abstract":"Multiphase flows, defined as a discrete phase in a continuous fluid phase, are found in many natural, industrial, and consumer flows, from rain fall and avalanches to petroleum processing and fuel combustion to cookie dough mixing and pasta making. Many of these flows have an interior that is hidden from optical flow measurements, and intrusive probes can modify the flows of interest. Noninvasive measurement techniques, like X-ray flow visualization, provide a means to visualize and quantify the flow conditions in areas obstructed to visual access. Additionally, X-rays are unlikely to modify or alter the flow of interest. This paper reviews various X ray flow visualization techniques, including those using X-rays from tube sources, electron guns, and synchrotron sources. X-ray fundamentals are first reviewed. Then, various X ray imaging techniques are highlighted, and applications of those techniques are summarized using several multiphase flow examples. Advantages and disadvantages of each technique are provided and the unique flow features that can be captured with X-ray flow visualization are summarized. As detailed, X-ray flow visualization is a powerful tool for multiphase flow visualization and characterization, particularly when the flow of interest has limited or no optical access.","PeriodicalId":504378,"journal":{"name":"Journal of Fluids Engineering","volume":"9 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139269818","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: 0

Improving 3D Synthetic Jet Modeling in a Crossflow 改进横流中的三维合成射流建模

Journal of Fluids Engineering Pub Date : 2023-11-16 DOI: 10.1115/1.4064185

Howard Ho, E. Essel, Pierre E. Sullivan

引用次数: 0