Experiments in Fluids最新文献_第2页

Spray interaction in adjacent GCSC injector elements: role of droplet collision and secondary droplet breakup 相邻GCSC喷射器元件中的喷雾相互作用：液滴碰撞和二次液滴破碎的作用

IF 2.3 3区工程技术

Experiments in Fluids Pub Date : 2025-01-05 DOI: 10.1007/s00348-024-03939-1

Surya Ghosh, Srikrishna Sahu

{"title":"Spray interaction in adjacent GCSC injector elements: role of droplet collision and secondary droplet breakup","authors":"Surya Ghosh, Srikrishna Sahu","doi":"10.1007/s00348-024-03939-1","DOIUrl":"10.1007/s00348-024-03939-1","url":null,"abstract":"<p>This study investigates the evolution of spray characteristics in adjacent gas-centered swirl coaxial (GCSC) injectors, which finds application in liquid propellant rocket engines. The main objectives here are to measure the axial evolution of droplet characteristics in the spray interaction zone and understand the fundamental physics governing the spray interaction process. Experiments were conducted using air and water as the working fluids under atmospheric conditions. Utilizing the high-speed shadow imaging technique, the droplet images were captured at different axial and radial measurement stations for gas-to-liquid momentum flux ratio (<i>M</i>) ranging from 30 to 70. The images were processed to obtain droplet size, axial/radial components of droplet velocity, and droplet mass flux. The Mie-scattering images of the spray were acquired by laser sheet imaging to visualize the spray structure and spatial distribution of the droplets. Droplet measurements were also obtained by operating the injectors individually. Comparative analysis between the interacting and individual sprays highlighted the significant reduction in characteristic droplet size and an increase in the mean droplet velocity and local mass flux due to spray interaction. To elucidate the physical mechanisms behind the above observations, further analysis was carried out by evaluating the droplet collision, secondary atomization, and droplet dispersion in the interaction zone. Interestingly, the results highlight that, despite the intuitive notion that droplet collisions are the primary driver of the spray interaction process in the intersecting sprays, the improved secondary droplet atomization due to modification of airflow characteristics serves as the dominant factor in altering the droplet characteristics.</p>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142925559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Holographic focusing schlieren imaging (HFSI) for three-dimensional flow visualization 三维流动可视化的全息聚焦纹影成像（HFSI）

IF 2.3 3区工程技术

Experiments in Fluids Pub Date : 2025-01-05 DOI: 10.1007/s00348-024-03951-5

Zhiming Lin, Yiqin Li, Aimin Xie, Kaihui Liu, Zhiliang Xue, Qiwen Jin, Yingchun Wu, Xuecheng Wu

{"title":"Holographic focusing schlieren imaging (HFSI) for three-dimensional flow visualization","authors":"Zhiming Lin, Yiqin Li, Aimin Xie, Kaihui Liu, Zhiliang Xue, Qiwen Jin, Yingchun Wu, Xuecheng Wu","doi":"10.1007/s00348-024-03951-5","DOIUrl":"10.1007/s00348-024-03951-5","url":null,"abstract":"<div><p>Flow field visualization techniques, e.g., schlieren and shadowgraphy, are indispensable in fluid mechanics research and application. In this paper, we present a novel technique, named holographic focusing schlieren imaging (HFSI), which takes only a single-camera and single-shot configuration to achieve three-dimensional (3D) flow visualization. The essence of this technique is that a coherent reference wave is introduced to interfere with the wavefront yielded by the traditional focusing schlieren (FS) method, forming a hologram. The reconstruction of the hologram directly yields the FS results along the test volume slice by slice with adjustable intervals, achieving 3D visualization. To demonstrate the capability of HFSI, a proof-of-concept setup was established, and experiments were performed using a compressed air jet, with a comparison to the FS method. The result shows that HFSI image reconstruction remarkably refocuses the out-of-focus jet flow, yielding similar schlieren effect observed in the FS images. The proposed HFSI holds significant practical value in some scenarios, such as in a wind tunnel, as it requires only one pair of parallel windows to achieve 3D flow visualization.</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142925560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Supersonic discharge of cold gas inflators into rectangular ducts 低温气体充气器在矩形管道内的超声速排放

IF 2.3 3区工程技术

Experiments in Fluids Pub Date : 2025-01-04 DOI: 10.1007/s00348-024-03932-8

Eduard Schnorr, Dennis Schütte, Peter Scholz, Rolf Radespiel

{"title":"Supersonic discharge of cold gas inflators into rectangular ducts","authors":"Eduard Schnorr, Dennis Schütte, Peter Scholz, Rolf Radespiel","doi":"10.1007/s00348-024-03932-8","DOIUrl":"10.1007/s00348-024-03932-8","url":null,"abstract":"<p>We discuss the supersonic discharge of cold gas inflators into confined ducts typical of curtain airbag inflation. The medium discharged from the cold gas inflators is helium. For this purpose, two different generic duct geometries are chosen to obtain one case without and one with wall interaction of the underexpanded jet. In the latter case, a so-called shock train develops, which dominates the flow topology. To quantify the flow field, time-resolved pressure transducers measure the static pressure at the duct walls and time-resolved particle image velocimetry measures the velocity in the far field of the underexpanded jet. Schlieren images illustrate the topology of the flow field. A simplified numerical model is then created that drastically reduces the required resources. The numerical model is verified against the experimental data and provides deeper insight into the outflow process. In particular, the interaction of the underexpanded jet with the duct walls and thus the resulting shock train are found to be sensitive. The numerical model can reconstruct the flow topology, pressure and velocity within acceptable limits. The experimental data and numerical results may serve as a basis for subsequent studies on airbag inflation or physically similar processes, especially for the validation of numerical methods.</p>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00348-024-03932-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142925417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Tomo-PIV measurement of small-scale structures in Newtonian and polymeric turbulence Tomo-PIV测量牛顿和聚合物湍流中的小尺度结构

IF 2.3 3区工程技术

Experiments in Fluids Pub Date : 2025-01-03 DOI: 10.1007/s00348-024-03948-0

Feng Wang, Yi-Bao Zhang, Heng-Dong Xi

{"title":"Tomo-PIV measurement of small-scale structures in Newtonian and polymeric turbulence","authors":"Feng Wang, Yi-Bao Zhang, Heng-Dong Xi","doi":"10.1007/s00348-024-03948-0","DOIUrl":"10.1007/s00348-024-03948-0","url":null,"abstract":"<div><p>The effects of polymer additives on turbulent fluid flows have attracted massive attention since the discovery of significant drag reduction by polymers in wall-bounded flows. Here we present an experimental study on the polymer–turbulence interaction at the center of the turbulent von Kármán swirling (VKS) flow system where the flow is far away from the boundary (bulk turbulence) with tomographic particle image velocimetry (Tomo-PIV). We used water–glycerol mixture to tune the viscosity of the working fluids, which facilitates us to resolve the dissipative scales and thus obtain all the nine components of the velocity gradient tensor directly. Our experiments demonstrate that at the center of the VKS flow, anisotropic properties extend from large scale to small scale, but gradually weaken with increasing Reynolds number. In polymeric turbulence, it is found that with increasing polymer concentration both the spatial averaged root mean square velocity and the average energy dissipation rate first decrease and then tend to stay at a constant value when concentration exceeds a critical value, implying that the effect of polymers saturates at high polymer concentration. We also find that the small scales become more anisotropic with the increasing concentration. The axisymmetry of small scales, however, is always retained, which can be employed to estimate the average energy dissipation rate from the planar PIV data. Moreover, we reveal that the number of the tube-like structures, the elementary structure in Newtonian turbulence, is strongly inhibited by the polymer additives, whereas the size of the tube-like structures is greatly enlarged.</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142912857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

An improved calibration methodology and uncertainty assessment in measurements of microbubble size and concentration 微泡尺寸和浓度测量中改进的校准方法和不确定度评定

IF 2.3 3区工程技术

Experiments in Fluids Pub Date : 2024-12-31 DOI: 10.1007/s00348-024-03929-3

R. Stigter, D. Fiscaletti, G. E. Elsinga, T. van Terwisga, J. Westerweel

引用次数: 0

Front–rear wheel interactions for a model vehicle: consequence for drag 模型车辆前后轮相互作用：对阻力的影响

IF 2.3 3区工程技术

Experiments in Fluids Pub Date : 2024-12-30 DOI: 10.1007/s00348-024-03950-6

Di Bao, Jacques Borée, Christophe Sicot, Côme Roebroeck

引用次数: 0

Three-dimensional density measurement around a Hayabusa re-entry capsule model in the ballistic range 隼鸟号返回舱模型在弹道范围内的三维密度测量

IF 2.3 3区工程技术

Experiments in Fluids Pub Date : 2024-12-27 DOI: 10.1007/s00348-024-03943-5

Masato Yamagishi, Masanori Ota, Kiyonobu Ohtani, Hiroki Nagai

引用次数: 0

Experimental approach to study mass transfer in liquid–liquid systems under vertical piston oscillations 垂直活塞振荡下液-液体系传质的实验研究

IF 2.3 3区工程技术

Experiments in Fluids Pub Date : 2024-12-26 DOI: 10.1007/s00348-024-03940-8

Elena Krasnyakova, Ivan Karpunin, Nikolai Kozlov

{"title":"Experimental approach to study mass transfer in liquid–liquid systems under vertical piston oscillations","authors":"Elena Krasnyakova, Ivan Karpunin, Nikolai Kozlov","doi":"10.1007/s00348-024-03940-8","DOIUrl":"10.1007/s00348-024-03940-8","url":null,"abstract":"<div><p>In the paper, a novel experimental setup is introduced that is designed to investigate the dynamics of two-layer liquid–liquid systems under vertical piston oscillations. It can operate within a wide range of fluid properties, including miscible and immiscible, reactive, and non-reactive pairs of liquids. The oscillations are driven by the motion of a high-precision linear motor, whose forcing is transmitted to fluids via membranes and a hydraulic circuit. The system’s flexibility allows for precise adjustment of vibration parameters (frequency and amplitude), facilitating a detailed examination of their effects on fluid dynamics. The setup developed is used in the present work for experiments on a two-layer system composed of aqueous sugar and salt solutions, focusing on the study of double-diffusive convection dynamics. Under oscillatory conditions, experimental results demonstrate a significant reduction in the mixing time between the salt and sugar solutions in the zone of contact between the layers, with nearly one order of magnitude enhancement in the mixing rate compared to non-vibrational experiments. Meanwhile, the oscillations have little impact on the development of finger patterns within the considered duration of experiments. This acceleration in mass transfer processes is attributed to the disruptive effect of oscillations on stable layer stratification, promoting efficient interlayer mixing. The findings underscore the potential applications of controlled vibrations in enhancing fluid mixing dynamics across various scientific and engineering disciplines, especially in real-world marine environments, such as improving oceanic productivity through enhanced mixing strategies.\u0000</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142889896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Measurements of buoyant plumes in a turbulent boundary layer 湍流边界层中浮力羽流的测量

IF 2.3 3区工程技术

Experiments in Fluids Pub Date : 2024-12-26 DOI: 10.1007/s00348-024-03941-7

Miaoyan Pang, Kapil Chauhan, K. M. Talluru

{"title":"Measurements of buoyant plumes in a turbulent boundary layer","authors":"Miaoyan Pang, Kapil Chauhan, K. M. Talluru","doi":"10.1007/s00348-024-03941-7","DOIUrl":"10.1007/s00348-024-03941-7","url":null,"abstract":"<div><p>This study presents a novel experimental setup designed to release a buoyant scalar plume and measure concentration and velocity simultaneously. Tracer gas is released from a point source in a low-Reynolds-number boundary layer (<span>(Re_tau approx 1600)</span>). The buoyant plume released consists of a mixture of varying proportions of tracer gas and a chemically stable base gas, resulting in density ratios relative to ambient air (<span>(rho _s/rho _infty)</span>) of 1.48, 1, and 0.15. The concentration of the tracer gas (iso-butylene) is detected using a photo-ionisation detector (PID) that ionises a small volume of the tracer gas within its chamber. Additionally, an <span>(times)</span>-wire is employed to measure the streamwise and vertical components of velocity. Results of the mean and root-mean-square (RMS) concentration profiles for the positively and negatively buoyant plumes exhibit a Gaussian or reflected-Gaussian behaviour similar to a neutral plume, albeit with altered parameters such as the plume centreline that now vary with <span>(rho _s/rho _infty)</span>. The data indicate that the half-width of the positively buoyant plume is wider than that of the neutral plume, and the spread of negatively buoyant plumes is thinner. Consequently, the maximum concentration of the negatively buoyant plume is the largest among the three <span>(rho _s/rho _infty)</span>. Although power laws are fitted to describe the downstream evolution of plume spread and maximum mean and RMS values of concentration, the accuracy of the fit appears to be limited.</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142889895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Fast 1D NMR imaging of clay sedimentation using a multi-slice stepper motor method 采用多片步进电机方法的粘土沉降快速一维核磁共振成像

IF 2.3 3区工程技术

Experiments in Fluids Pub Date : 2024-12-23 DOI: 10.1007/s00348-024-03937-3

Nick J. Hol, Leo Pel, Martijn Kurvers, Claire Chassagne

{"title":"Fast 1D NMR imaging of clay sedimentation using a multi-slice stepper motor method","authors":"Nick J. Hol, Leo Pel, Martijn Kurvers, Claire Chassagne","doi":"10.1007/s00348-024-03937-3","DOIUrl":"10.1007/s00348-024-03937-3","url":null,"abstract":"<div><p>This study introduces a fast 1D nuclear magnetic resonance (NMR) imaging method based on multi-slice imaging with a stepper motor to study sedimentation dynamics of clayey soils. Traditional NMR is limited by long acquisition times due to water’s <i>T</i><sub>1</sub> relaxation time. Our approach combines multi-slice imaging with a stepper motor and frequency-based selection, reducing measurement time while maintaining sub-millimeter resolution, at the same time overcoming the limitations by the slow relaxation of water. This nondestructive method provides detailed insights into the sedimentation and consolidation of suspensions, including pore size distribution and density profiles within a single measurement. The technique is demonstrated with kaolinite clay suspensions, highlighting the technique’s ability to capture the dynamics of gravity-driven systems rapidly and accurately, even for fast-sedimenting soils such as kaolinite in the first hours of sedimentation. This advancement is valuable for geotechnical and environmental applications where understanding sedimentation is crucial.</p><h3>Graphical abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142875206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0