Experiments in Fluids最新文献_第4页

Four-view single-camera plenoptic 3.0 imager for three-dimensional Lagrangian particle tracking in an oscillatory laminar boundary layer 振荡层流边界层中三维拉格朗日粒子跟踪的四视单相机全光学3.0成像仪

IF 2.5 3区工程技术

Experiments in Fluids Pub Date : 2025-08-12 DOI: 10.1007/s00348-025-04095-w

Mark J. Yamakaitis, Anis Rezaiguia, Charles Fort, Roberto Capanna, Philippe M. Bardet

{"title":"Four-view single-camera plenoptic 3.0 imager for three-dimensional Lagrangian particle tracking in an oscillatory laminar boundary layer","authors":"Mark J. Yamakaitis, Anis Rezaiguia, Charles Fort, Roberto Capanna, Philippe M. Bardet","doi":"10.1007/s00348-025-04095-w","DOIUrl":"10.1007/s00348-025-04095-w","url":null,"abstract":"<div><p>We show a novel plenoptic camera architecture and demonstrate its ability to perform three-dimensional three-component velocimetry using standard multi-camera processing techniques. The field of view of the imager is approximately <span>(10~text {mm}times 7~text {mm}times 3,text {mm})</span>. The architecture needs only a custom lens assembly with no modification to the camera body, which allows the use of any camera with an appropriate sensor size. This plenoptic configuration directly creates multiple views of a scene side by side on the camera sensor, which are then separated and treated as if they originated from independent cameras. Standard calibration techniques are implemented to create 3D to 2D correspondence on images to determine 3D scene information. 3D velocity fields are reconstructed with the “shake-the-box” implementation of Lagrangian particle tracking. Results are validated with an axially oscillating cylinder in a refractive-index-matched experiment. The flow is the axisymmetric equivalent of Stokes second problem for which an analytical solution is known. The boundary layer is <span>(1.24~textrm{mm})</span> with large accelerations and velocity gradients, which serve as a strong test case for the instrument.</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 9","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144814385","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

Instantaneous refractive index compensation on the velocity measurement using simultaneous PIV-BOST 瞬时折射率补偿对同步PIV-BOST速度测量的影响

IF 2.5 3区工程技术

Experiments in Fluids Pub Date : 2025-08-12 DOI: 10.1007/s00348-025-04093-y

Yutao Zheng, Yuanzhe He, Jingruo Chen, Minshuo Li, Shijie Xu, Bi Wen, Yingzheng Liu, Weiwei Cai

{"title":"Instantaneous refractive index compensation on the velocity measurement using simultaneous PIV-BOST","authors":"Yutao Zheng, Yuanzhe He, Jingruo Chen, Minshuo Li, Shijie Xu, Bi Wen, Yingzheng Liu, Weiwei Cai","doi":"10.1007/s00348-025-04093-y","DOIUrl":"10.1007/s00348-025-04093-y","url":null,"abstract":"<div><p>This study has firstly provided an instantaneous refractive index compensation on velocity measurement in a reacting field where the 3D refractive index and the velocity distribution were measured by Background-oriented Schlieren tomography (BOST) and planar particle image velocimetry (PIV). A one-to-nine endoscope system was integrated with a camera to provide nine views of a turbulent non-piloted Bunsen flame. The 3D refractive index field was reconstructed from a neural network. A low-speed PIV system was applied to capture 2D velocity distribution across the central plane simultaneously. To synchronise the BOST system with PIV, two digital delay/pulse generators were synchronised to generate two groups of signals with different frequencies for two systems with a fixed phase delay. The pixel shifting on the PIV plane was resolved by estimating the gradient of the thermal-induced refractive index between the PIV camera and the imaging plane. The magnitude of the <i>instantaneous</i> velocity error caused by the light deflection was estimated (<span>(pm ,2%)</span>) for a small non-pilot flame. By inversely considering the velocity error, the error effect caused by the instantaneous refractive index displacement was firstly removed. Such a technique provides a well-defined method that can resolve the same velocity error in PIV measurement in larger flames, significantly improving the accuracy of PIV in reacting flows.</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 9","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144814384","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

Experimental identification on separated and merged sound-induced vortices along lined slit–cavities under flow-convection effect 流对流作用下沿缝腔分离和合并声诱导涡的实验识别

IF 2.5 3区工程技术

Experiments in Fluids Pub Date : 2025-08-07 DOI: 10.1007/s00348-025-04089-8

Yuchao Tang, Peng Wang, Yingzheng Liu

{"title":"Experimental identification on separated and merged sound-induced vortices along lined slit–cavities under flow-convection effect","authors":"Yuchao Tang, Peng Wang, Yingzheng Liu","doi":"10.1007/s00348-025-04089-8","DOIUrl":"10.1007/s00348-025-04089-8","url":null,"abstract":"<div><p>This study presents an experimental investigation into the vortex dynamics within lined slit–cavities subjected to coupled grazing flow and acoustic excitation. Central to this investigation is the role of velocity ratio <span>({U}^{*})</span> (defined as the ratio of mainstream velocity to acoustic particle velocity) within the range of 0 to 56.6 in modulating flow-acoustic characteristics. An experimental setup integrating microphones, pressure transducer arrays, and particle image velocimetry (PIV) systems was developed to synchronously capture acoustic responses, pressure fluctuations, and unsteady flow behaviors. Crucially, the PIV system incorporated a field-programmable gate array, leveraging its real-time computation capability to ensure precise synchronization of acoustic-fluidic interactions during phase-locked measurements. Transmission loss analysis reveals a critical threshold at <span>({U}^{*}=)</span> 14.9 that bifurcates the acoustic response into two distinct regimes: weak influence regime (0 <span>(le {U}^{*}<)</span> 14.9) and strong influence regime (14.9 <span>(<{U}^{*}le)</span> 56.6). Subsequently, the time-averaged flow fields and spatiotemporal vortex evolution characteristics were comparatively investigated in two distinct regimes. In contrast to the symmetric vortex evolution observed in the absence of grazing flow, two distinct evolution patterns are identified: a separated vortex evolution under weak flow-convection effects and a merged vortex evolution under strong flow-convection effects. The systematic analysis of acoustic-vortex conversion efficiency was conducted sequentially through pressure fluctuations, velocity fluctuations, and dominant modes. The results reveal that high-speed grazing flow significantly suppresses coherent structures within the slit.</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 9","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145163159","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

Transfer efficiency and area coverage of spray droplets impacting planar surfaces 喷雾液滴撞击平面的传递效率和覆盖面积

IF 2.5 3区工程技术

Experiments in Fluids Pub Date : 2025-08-06 DOI: 10.1007/s00348-025-04087-w

Mazin Tahir, Khalil Sidawi, Peter Anthony Di Palma, Sanjeev Chandra

{"title":"Transfer efficiency and area coverage of spray droplets impacting planar surfaces","authors":"Mazin Tahir, Khalil Sidawi, Peter Anthony Di Palma, Sanjeev Chandra","doi":"10.1007/s00348-025-04087-w","DOIUrl":"10.1007/s00348-025-04087-w","url":null,"abstract":"<div><p>An experimental study was conducted to measure spray transfer efficiency, defined as the mass fraction of sprayed droplets that adhere to a target surface, and the rate of surface coverage by impacting droplets. The objective was to determine how transfer efficiency and surface coverage rates vary with droplet size distribution and air velocity, which is important in selecting spray parameters in painting and coating applications. The study was conducted using a wind tunnel consisting of a 6.5-cm-diameter tube connected to a tubular fan, producing controlled airflow velocities from 2 to 9 m/s. Sprays of canola oil or a 33 vol% glycerin–water mixture were introduced into the airstream and directed toward a 10-cm-diameter target disk, where the mass of deposited droplets was measured to evaluate transfer efficiency. Transfer efficiency was calculated by dividing the total target weight change by the weight of liquid sprayed. Droplet diameter distributions were measured using a direct imaging method. A high-speed camera was used to photograph droplets landing on the substrate and the rate of area coverage by impacting droplets measured. Transfer efficiency and surface coverage rates increase with airstream velocity. Larger droplets, whose motion is dominated by inertia, have a higher probability of reaching the target and a higher transfer efficiency. Below a critical Stokes number (St < 0.25), droplets fail to reach the target, irrespective of velocity. Droplet trajectories were modeled using an analytical solution to the inviscid stagnation flow problem to determine air velocities and calculate drag forces on droplets. A stochastic model of droplet transport and deposition accurately predicts transfer efficiencies and rates of surface coverage, except at higher (> 5 m/s) velocities where turbulence in the flow increases.</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 8","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145162764","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

Thermal compensation in recessed piezoresistive probes to improve absolute pressure measurements in rotating detonation engines 内嵌式压阻探头的热补偿改进旋转爆震发动机的绝对压力测量

IF 2.5 3区工程技术

Experiments in Fluids Pub Date : 2025-08-06 DOI: 10.1007/s00348-025-04086-x

Robert S. Miller, Ajay K. Agrawal, John P. Hilton

{"title":"Thermal compensation in recessed piezoresistive probes to improve absolute pressure measurements in rotating detonation engines","authors":"Robert S. Miller, Ajay K. Agrawal, John P. Hilton","doi":"10.1007/s00348-025-04086-x","DOIUrl":"10.1007/s00348-025-04086-x","url":null,"abstract":"<div><p>Piezoresistive (PR) probes can provide absolute pressure measurements, but their practical use in rotating detonation engines (RDEs) has been hindered by the harsh thermal environment of the combustion chamber. In general, the probe must be recessed to protect it from intense thermal loading of the RDE combustor. Although probe recess safeguards the hardware, measurements are subjected to thermal drift, in addition to signal attenuation, phase shift, and resonance. In this study, four different recess probe mounts are investigated experimentally in an RDE to account for the thermal drift in PR probes. A modified Wheatstone bridge is used to measure the sensor temperature during the test, and a steady-state methodology is employed for thermal compensation. Results show that all probe mount configurations provide time-varying pressure measurements with good accuracy, although pressure attenuation is greater with a smaller port diameter. The study identified that absolute and/or time-averaged pressure measurements incur large errors in a non-isothermal probe during the RDE test. Accurate absolute pressure measurements by PR pressure probes can be obtained in RDEs, but it requires a probe mount to ensure an isothermal probe during the test.</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 8","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145162611","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

PIV in the vicinity of cork samples in particle-laden high-enthalpy flow 含颗粒高焓流中软木试样附近的PIV

IF 2.5 3区工程技术

Experiments in Fluids Pub Date : 2025-08-05 DOI: 10.1007/s00348-025-04083-0

Ciro Salvi, Ali Gülhan

{"title":"PIV in the vicinity of cork samples in particle-laden high-enthalpy flow","authors":"Ciro Salvi, Ali Gülhan","doi":"10.1007/s00348-025-04083-0","DOIUrl":"10.1007/s00348-025-04083-0","url":null,"abstract":"<p>This research aims at analysing the particle-laden flow of the high-enthalpy wind tunnel L2K, which is used to characterize the impact of dust particles on the recession behaviour of thermal protection systems during Martian entry flight. In the tests, a slightly simplified Martian atmosphere (<span>({text{97% CO}}_{{text{2}}})</span> and <span>({text{3% N}}_{{text{2}}})</span>) is used. The high-enthalpy flow is loaded with micrometric particles of magnesium oxide. Several samples for stagnation point tests made of P50 cork are positioned inside the particle-laden flow. The particles’ mean velocity is measured at the stagnation point of the probe in a region of interest that includes the free stream and the shock layer, with a 2D-2C particle image velocimetry (PIV) system. Several particle flow features are observed, such as the particle’s steep velocity gradient across the shock, the shock layer, and a counter-flow that might be caused by outgassing and rebounded particles. Average particle velocities ranging from 0 to 2100 m/s are measured and compared with the numerical simulation of the wind tunnel’s particle-free flow. A discussion on particle agglomeration due to melting is reported, and the importance of considering this effect for the simulation of atmospheric entry in particle-laden atmospheres is highlighted. Particles are collected with double-sided copper tape on a cooled probe and analysed with a scanning electron microscope (SEM) and with energy-dispersive X-ray spectroscopy (EDX), to characterize their morphological change during their residence time in the wind tunnel flow.</p>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 8","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00348-025-04083-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145162036","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

Planar laser-based measurements of droplet size, volume fraction, and velocity in flow-blurring sprays 流动模糊喷雾中液滴尺寸、体积分数和速度的平面激光测量

IF 2.5 3区工程技术

Experiments in Fluids Pub Date : 2025-08-04 DOI: 10.1007/s00348-025-04075-0

Surendra Kumar Soni, Abhishek Kumar Gupta, Keshav Yadav, Yogeshwar Nath Mishra, Santanu De

{"title":"Planar laser-based measurements of droplet size, volume fraction, and velocity in flow-blurring sprays","authors":"Surendra Kumar Soni, Abhishek Kumar Gupta, Keshav Yadav, Yogeshwar Nath Mishra, Santanu De","doi":"10.1007/s00348-025-04075-0","DOIUrl":"10.1007/s00348-025-04075-0","url":null,"abstract":"<div><p>We employ advanced laser-based diagnostics to investigate the spray characteristics of a custom-designed flow-blurring (FB) atomizer. Structured Laser Illumination Planar Imaging (SLIPI)-based methods are utilized to obtain two- and three-dimensional (2D–3D) maps of the droplet Sauter Mean Diameter (SMD) and planar liquid volume fraction, while the conventional particle image velocimetry is used to measure droplet velocities within the spray in 2D. Water and ethanol sprays are investigated across a range of air-to-liquid mass ratios (ALRs = 2–5). The SLIPI-based fluorescence/scattering ratio maps of droplet relative SMD are calibrated and compared using the Phase Doppler Particle Analyzer data, demonstrating strong agreement with a low mean absolute percentage error (MAPE), especially at lower ALR. However, at higher ALR, the optically dense sprays result in increased multiple scattering effects, leading to higher MAPE values. SLIPI effectively captures the transient and polydisperse nature of FB sprays, with droplet size distributions closely following a gamma function. Additionally, a correlation for SMD is developed in terms of key non-dimensional groups, which represent the geometric parameters, physical properties of the working fluid, and spatial locations within the spray. The relevant dimensionless groups in the SMD correlation based on the geometric and physical properties are Laplace number (300-9700), liquid Reynolds number (<span>(text{Re}_l=95)</span> and 140), and Ohnesorge number (<span>(text{Oh}=0.0027)</span> and 0.0065).</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 8","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00348-025-04075-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145161402","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

Vision-based tracking of orientation and velocity for non-spherical particles 基于视觉的非球形粒子方向和速度跟踪

IF 2.5 3区工程技术

Experiments in Fluids Pub Date : 2025-08-03 DOI: 10.1007/s00348-025-04082-1

Simon Eberhard, Christian Lundgaard, Jeppe Heering Holt, Jens Honore Walther, Knud Erik Meyer

{"title":"Vision-based tracking of orientation and velocity for non-spherical particles","authors":"Simon Eberhard, Christian Lundgaard, Jeppe Heering Holt, Jens Honore Walther, Knud Erik Meyer","doi":"10.1007/s00348-025-04082-1","DOIUrl":"10.1007/s00348-025-04082-1","url":null,"abstract":"<div><p>A stereo camera method for tracking the position and orientation of rigid non-spherical particles is presented. The method works by comparing the images of the observed particle with that of a geometric model of the observed particle. The comparison of images is formulated as an optimization problem that determines the position and orientation of the particle at each time step. The optimization problem is solved using gradient descent by implementing the objective function in the differentiable programming library PyTorch. The method is validated using synthetic data, demonstrating robustness to both regular and irregular particle shapes. The influence of image noise, pixel density, and the resolution of the geometric model on the accuracy of the recovered position and orientation is addressed, and the results show sub-pixel accuracy to around 0.3 pixels at realistic experimental conditions. Finally, the method is applied to an experiment of non-spherical particles settling in a quiescent flow. Three regular and ten irregular particles are used, with particle Reynolds numbers ranging between 200 and 800. The results show that the instantaneous vertical velocity of the particles can vary by up to 50% due to changes in orientation. Different settling modes are identified, highlighting the importance of tracking all 6<span>(^circ)</span> of translational and rotational freedom to capture the dynamics of settling non-spherical particles.</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 8","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00348-025-04082-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145161498","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

A precise phosphorescent-decay particle tracking method based on Gaussian intensity optimization for simultaneous temperature and velocity measurements 一种同时测量温度和速度的基于高斯强度优化的磷光衰变粒子精确跟踪方法

IF 2.5 3区工程技术

Experiments in Fluids Pub Date : 2025-08-02 DOI: 10.1007/s00348-025-04081-2

Di Luan, Ruiyu Fu, Di Peng, Yingzheng Liu, Tao Cai

{"title":"A precise phosphorescent-decay particle tracking method based on Gaussian intensity optimization for simultaneous temperature and velocity measurements","authors":"Di Luan, Ruiyu Fu, Di Peng, Yingzheng Liu, Tao Cai","doi":"10.1007/s00348-025-04081-2","DOIUrl":"10.1007/s00348-025-04081-2","url":null,"abstract":"<div><p>The study of heat and mass transfer in thermal fluids relies on simultaneous temperature and velocity measurement techniques, and temperature-sensitive phosphor-particle-based velocimetry is an effective tool. Among the available methods, the lifetime method performs well in simplicity and precision. However, it faces challenges when capturing the position and phosphorescence intensity of a particle as it moves and decays. A precise phosphorescent-decay particle tracking (PDPT) method based on Gaussian intensity optimization was proposed in this study for phosphorescent particles whose center positions are coupled with the phosphorescence intensity. The PDPT method precisely obtains the center positions and phosphorescence intensities of moving phosphor particles that occupy only a few pixels in a single image, thereby enhancing the accuracy of thermometry and velocimetry. Tests with numerically synthesized particles and experimental measurements were employed to validate the proposed method, which achieved a relative trajectory error of < 0.25% at a particle velocity of 200 pixel/s and a relative temperature error of < 0.05% at 473 K. Compared with existing approaches, the PDPT method showed significant improvements in the tracking ability of the center positions and intensities of individual particles, representing a notable enhancement in the simultaneous temperature and velocity measurement of thermal fluids.</p><h3>Graphical abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 8","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145160788","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

Experimental study of the flow around a near-wall rectangular cylinder 近壁矩形圆柱绕流的实验研究

IF 2.5 3区工程技术

Experiments in Fluids Pub Date : 2025-08-02 DOI: 10.1007/s00348-025-04085-y

Xin Liu, Jiang-Hua Li, Yu-Ze Wang, Xiang Qiu, Jia-Hua Li, Yu-Lu Liu

{"title":"Experimental study of the flow around a near-wall rectangular cylinder","authors":"Xin Liu, Jiang-Hua Li, Yu-Ze Wang, Xiang Qiu, Jia-Hua Li, Yu-Lu Liu","doi":"10.1007/s00348-025-04085-y","DOIUrl":"10.1007/s00348-025-04085-y","url":null,"abstract":"<div><p>This study experimentally investigates the flow around a near-wall rectangular cylinder at a Reynolds number of <span>(Re_D = 1000)</span>, focusing on the influence of gap ratios (<span>(G/D = 0.5, 1.0, 2.0)</span>) and aspect ratios (<span>(L/D = 3, 6, 9)</span>). The results demonstrate that both parameters profoundly impact vortex dynamics and turbulence characteristics. At small <span>(G/D)</span>, near-wall effect suppresses lower leading edge vortex formation and leads to asymmetric recirculation. As <span>(G/D)</span> increases, the flow becomes more symmetric, and vortex shedding from both the upper and lower sides intensifies, forming Kármán vortex streets at suitable <span>(L/D)</span>. The behavior of secondary vortices and their interaction with primary wake vortices vary significantly with geometry, influencing their development into coherent boundary layer structures or their entrainment into the wake. The fluctuations grow with increasing <span>(G/D)</span> and are especially strong at <span>(L/D = 3)</span> due to enhanced wake oscillations. Wall-normal integrated velocity fluctuations reveal that leading edge and trailing edge vortex shedding contributes comparably to turbulence production, particularly at larger gap ratios, where clear bimodal distributions are observed.</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 8","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145160789","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