Journal of Fluids Engineering最新文献_第3页

Special Issue on the 2023 ASME - JSME - KSME Fluids Engineering Division Summer Meeting 2023 年 ASME - JSME - KSME 流体工程分部夏季会议特刊

Journal of Fluids Engineering Pub Date : 2024-04-12 DOI: 10.1115/1.4065305

Francine Battaglia

引用次数: 0

Effect of Tip Gap Size On the Tip Flow Structure and Turbulence Generation in a Low Reynolds Number Compressor Cascade 尖端间隙大小对低雷诺数压缩机级联中尖端流结构和湍流产生的影响

Journal of Fluids Engineering Pub Date : 2024-04-11 DOI: 10.1115/1.4065295

Lei Shi, Hongwei Ma, Huajie Wang, Tianyou Wang

{"title":"Effect of Tip Gap Size On the Tip Flow Structure and Turbulence Generation in a Low Reynolds Number Compressor Cascade","authors":"Lei Shi, Hongwei Ma, Huajie Wang, Tianyou Wang","doi":"10.1115/1.4065295","DOIUrl":"https://doi.org/10.1115/1.4065295","url":null,"abstract":"\u0000 Efficient and compact axial compressors are currently undergoing rapid development for use in micro-cooling systems and small-scale vehicles. Limited experimental work concentrates on the inner flow field of the compressors working at such low Reynolds numbers (Re ~ 104). This study examines the vortical structures and the resulting turbulence production in the transitional flow over a C4 compressor blade at a Reynolds number Re of 24000, with a specific focus on the impact of tip clearance. The particle image velocimetry measurements reveal the tip flow structures in detail, including the tip leakage vortex (TLV) and its induced complex vortical structures. The tip secondary flow at the low Reynolds number can be divided as the tip leakage flow/vortex and transitional boundary layer both at the end walls and the blade surfaces. The TLV propagates at the highest spanwise positions and farthest pitchwise positions at the middle tip gap size (τ/C = 3%) for the three tip gap sizes investigated. The tip flow fluctuations decrease from τ/C = 5% to τ/C = 3% and then increase from τ/C = 3% to τ/C = 1%. The spatial distribution, streamwise evolution, and individual Reynolds normal stress components contributing to the turbulent kinetic energy (TKE) are discussed. The primary contributors to the turbulence generation are examined to elucidate the flow mechanism leading to the distinct anisotropic turbulence structure in the tip region with various tip gap sizes.","PeriodicalId":504378,"journal":{"name":"Journal of Fluids Engineering","volume":"48 S1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140715909","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

Vortex Identification Method Based On Topological Analysis and Velocity Gradient Invariance 基于拓扑分析和速度梯度不变性的涡流识别方法

Journal of Fluids Engineering Pub Date : 2024-04-11 DOI: 10.1115/1.4065293

Xiaoyun Qu, Rong He, Tong Wang

引用次数: 0

Experimental and Numerical Study of the Flow Around Rigid and Flexible Hydrofoils for Wetted and Cavitating Flow Conditions 湿流和气穴流条件下刚性和柔性水翼周围流动的实验和数值研究

Journal of Fluids Engineering Pub Date : 2024-04-11 DOI: 10.1115/1.4065296

P. Perali, F. Hauville, A. Leroyer, J. Astolfi, Michel Visonneau

{"title":"Experimental and Numerical Study of the Flow Around Rigid and Flexible Hydrofoils for Wetted and Cavitating Flow Conditions","authors":"P. Perali, F. Hauville, A. Leroyer, J. Astolfi, Michel Visonneau","doi":"10.1115/1.4065296","DOIUrl":"https://doi.org/10.1115/1.4065296","url":null,"abstract":"\u0000 The hydroelastic response of a flexible NACA 0015 hydrofoil is investigated for both wetted and cavitating flow conditions. Computational Fluid Dynamics (CFD) analysis are performed using a fully implicit coupling between the ISIS-CFD solver (developed by the METHRIC team at Ecole Centrale de Nantes) and a modal approach for the structure. The RANS (Reynolds Averaged Navier-Stokes) solver is first validated for wetted and cavitating flow conditions around a similar rigid hydrofoil, with experimental results carried out at the hydrodynamic tunnel of the French Naval Academy, including lift and drag measurements and high speed camera images. Then the numerical predictions for the flexible hydrofoil response are compared with experimental bending shapes and vibrations amplitudes, with a focus on cavitating flow conditions. For wetted flow conditions, numerical results show a good agreement with the experiments, for both rigid and flexible hydrofoils. For cavitating flow conditions, the hydroelastic response is dominated by vibrations at the hydrofoil modal frequencies and the re-entrant jet instability frequency. For the lowest values of the cavitation parameter, a large amplitude peak is experimentally observed in the frequency response spectra, due to lock-in between the first modal frequency and the re-entrant jet frequency. Strong harmonics of this dominant peak also appear in the spectra, revealing a non-linear response of the hydrofoil. While the amplitudes of vibrations are well predicted by the computations, the frequency lock-in observed in the experiments is not captured by the numerical model.","PeriodicalId":504378,"journal":{"name":"Journal of Fluids Engineering","volume":"14 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140715603","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

Effects of Leading-Edge Blowing Control and Reduced Frequency on Aerofoil Aerodynamic Performances 前缘吹风控制和降低频率对机翼气动性能的影响

Journal of Fluids Engineering Pub Date : 2024-04-11 DOI: 10.1115/1.4065294

Yang Chen, E. Avital, John Williams, Srimanta Santra, Avraham Seifert

{"title":"Effects of Leading-Edge Blowing Control and Reduced Frequency on Aerofoil Aerodynamic Performances","authors":"Yang Chen, E. Avital, John Williams, Srimanta Santra, Avraham Seifert","doi":"10.1115/1.4065294","DOIUrl":"https://doi.org/10.1115/1.4065294","url":null,"abstract":"\u0000 Aerofoil leading-edge fluid-blowing control is computationally studied to improve aerodynamic efficiency. The fluid injection momentum coefficient Cu (the ratio of injection to incoming square velocities times the slot's width to aerofoil's half chord-length), varies from 0.5% to 5.4%. Both static and dynamic conditions are investigated for a NACA0018 aerofoil at low speed and Reynolds number of 250k based on the aerofoil's chord-length. The aerofoil is dynamically pitched at at a reduced frequency (the pitching tangential speed to the free-stream speed ratio), varying between 0.0078 to 0.2. RANS and Unsteady RANS (URANS) are used in the simulations as based on the Transition SST and Spalart-Allmaras models, generally achieving good agreement with experimental results in lift and drag coefficients and in the pressure coefficient distributions along the aerofoil. It is found that oscillating the aerofoil can delay stall, as expected, in dynamic stall. Leading-edge blowing control can also significantly delay stall both in static and dynamic conditions as long as sufficient momentum is applied to the control. On the other hand, for a small Cu such as 0.5%, the leading-edge control worsens the performance and hastens the appearance of stall in both static and dynamic conditions. The aerofoil's oscillation reduces the differences between pitch-up and pitch-down aerodynamic performances. Detailed analysis of vorticity, pressure, velocity and streamline contours are given to provide plausible explanations and insight to the flow.","PeriodicalId":504378,"journal":{"name":"Journal of Fluids Engineering","volume":"16 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140712912","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

Time-Averaged Parameters of the Circular Synthetic Jet for Different Dimensionless Stroke Length 不同无量纲冲程长度下圆形合成射流的时间平均参数

Journal of Fluids Engineering Pub Date : 2024-04-03 DOI: 10.1115/1.4065228

Emil Smyk, P. Gil, Joanna Wilk

引用次数: 0

Influence of a Pair of Unequal Rotational Fluxes On Entrained Gaseous Filament 一对不相等的旋转通量对夹带气态纤维的影响

Journal of Fluids Engineering Pub Date : 2024-04-03 DOI: 10.1115/1.4065263

Santosh Kumar Panda, B. Rana

{"title":"Influence of a Pair of Unequal Rotational Fluxes On Entrained Gaseous Filament","authors":"Santosh Kumar Panda, B. Rana","doi":"10.1115/1.4065263","DOIUrl":"https://doi.org/10.1115/1.4065263","url":null,"abstract":"\u0000 Efforts are made to elucidate a comprehensive analysis of entrainment dynamics triggered by a couple of unequal rotational fluxes within a viscous pool. Cylindrical rollers are employed to establish the rotational field. The top drum is equally submerged in both phases and also it provides a constant rotational inertia. Concomitantly, the bottom roller is completely submerged in the viscous bath, and it provides an unequal rotational strength in reference to top roller. The average rotational strength of both rollers is measured using average Capillary number (Ca)avg. The entrainment phenomenon is strongly influenced by both Caavg and gap between the rollers (W/D). Characterization of entrained filament is elucidated by predicting the horizontal distance (L*), radial distance (r*), temporal vertical displacement (Y*), maximum vertical displacement (Ymax*), width (H*), and location of V-shaped diversion (∅s*). Characterization of liquid tip is performed by measuring the travel rate (Y*) along periphery of drum from receding to advancing junction. Air mass ejection from filament tip is analysed by estimating the 1st bubble ejection time (t1st*), volume of accumulated of ejected gaseous masses (v*), and ejection frequency (f). Furthermore, the effect of gravitational pull (specified by Archimedes number, Ar) and viscous drag (measured by Morton number, Mo) on the pattern of entrained air filament is described. Lastly, an analytical framework is established to determine the width of the V-junction by balancing the important influencing forces, which are strongly affecting the filament. Analytical observations show a satisfactory agreement with numerical findings.","PeriodicalId":504378,"journal":{"name":"Journal of Fluids Engineering","volume":"839 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140749363","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

Effects of Reynolds Number On the Wake Characteristics of a Notchback Ahmed Body 雷诺数对凹背艾哈迈德机体气流特性的影响

Journal of Fluids Engineering Pub Date : 2024-04-01 DOI: 10.1115/1.4065225

Newton F. Ouedraogo, E. Essel

{"title":"Effects of Reynolds Number On the Wake Characteristics of a Notchback Ahmed Body","authors":"Newton F. Ouedraogo, E. Essel","doi":"10.1115/1.4065225","DOIUrl":"https://doi.org/10.1115/1.4065225","url":null,"abstract":"\u0000 This paper investigates the effects of Reynolds number on the wake characteristics of a notchback Ahmed body with effective backlight angle, βe = 17.8°. The Reynolds number based on the body height was varied from 5 × 103 to 5 × 104. Prior to the Reynolds number investigation, a Reynolds-Averaged Navier-Stokes (RANS) model assessment was performed using nine turbulence models consisting of one- and two-equation eddy-viscosity models and second moment closure models. The standard Spalart-Allmaras model was the only model that accurately predicted the asymmetric time-averaged wake topology, as reported in previous studies, for the βe = 17.8° notchback Ahmed body at Re = 5 × 104. The drag coefficient decreased with increasing Reynolds number, while the lift coefficient remained constant for Re = 1 × 104. The wake structure exhibited three regimes: symmetric (Re = 1 × 104), transitionally asymmetric (1 × 104< Re = 3.5 × 104) and fully asymmetric (Re ≤ 3.5 × 104) states. The wake asymmetry was attributed to an imbalance in entrainment from the side and asymmetric separation from the roof and the C-pillars of the body. The tilting and stretching terms in the vorticity transport equation were used to provide insight into the source of asymmetry in the vorticity field around the body.","PeriodicalId":504378,"journal":{"name":"Journal of Fluids Engineering","volume":"6 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140793623","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

A Simple Predictive Method for Estimating Bor Over Time in a Cryogenic Container 估算低温容器中 Bor 随时间变化的简单预测方法

Journal of Fluids Engineering Pub Date : 2024-04-01 DOI: 10.1115/1.4065220

Chan-Soo Kim, Taehoon Kim, Hwalong You, Minchang Kim, Yong-Shik Han, Byung-Il Choi, Kyuhyung Do

引用次数: 0

Influence of Permeability and Shear-Thinning Behavior On the Hydrodynamics Flow Features Around Porous Square Cylinders 渗透性和剪切稀化行为对多孔方柱周围流体力学流动特征的影响

Journal of Fluids Engineering Pub Date : 2024-03-22 DOI: 10.1115/1.4065150

S. Jamshed, A. Dhiman

{"title":"Influence of Permeability and Shear-Thinning Behavior On the Hydrodynamics Flow Features Around Porous Square Cylinders","authors":"S. Jamshed, A. Dhiman","doi":"10.1115/1.4065150","DOIUrl":"https://doi.org/10.1115/1.4065150","url":null,"abstract":"\u0000 This article investigates the laminar flow of power-law fluids through two identical porous square cylinders in a side-by-side configuration within a channel. The effects of three critical parameters, power-law index (n), Darcy number (Da), and gap ratio (g/W) on the flow behavior are explored for ranges of g/W=0.5-5, n=0.4-0.8, and Da=10-6-10-2, respectively. Two flow conditions are considered: first, for a creeping flow (unseparated flow) at Re=1 where only Darcy's law is applicable; second, for a viscous dominant flow at Re=100, where Darcy-Forchheimer extended model is exercised. The flow patterns behind the porous square cylinders are analyzed using streamlines, velocity profiles, pressure distribution curves, and vorticity structural parameters (Г). In low permeability levels, the flow exhibits an irregular non-periodic vortex shedding characterized by a single large vortex street far-off the downstream for g/W=0.5. However, synchronized wake patterns were observed in either anti-phase or in-phase modes for higher gap ratios. The presence of a jet-like flow in the square cylinders' gap section significantly influences unsteady wake patterns. The impact of g/W, power-law index, and permeability on drag is also examined. The study findings provide valuable insights into flow behavior and offer a potential approach for improving the design of fluidic systems that involve porous cylinders.","PeriodicalId":504378,"journal":{"name":"Journal of Fluids Engineering","volume":" 15","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140216009","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