Experiments in Fluids最新文献

TWISTER (Twente water injection system for turbulence experimental research): a jet array in the Twente water tunnel for generating strong turbulence using four-dimensional gradient noise TWISTER (Twente water injection system for turbulence experimental research)：在Twente水洞内利用四维梯度噪声产生强湍流的射流阵列

IF 2.5 3区工程技术

Experiments in Fluids Pub Date : 2025-09-14 DOI: 10.1007/s00348-025-04103-z

Duco van Buuren, Dennis P. M. van Gils, Gert-Wim Bruggert, Dominik Krug

{"title":"TWISTER (Twente water injection system for turbulence experimental research): a jet array in the Twente water tunnel for generating strong turbulence using four-dimensional gradient noise","authors":"Duco van Buuren, Dennis P. M. van Gils, Gert-Wim Bruggert, Dominik Krug","doi":"10.1007/s00348-025-04103-z","DOIUrl":"10.1007/s00348-025-04103-z","url":null,"abstract":"<div><p>We present a newly constructed jet array with a novel driving scheme for turbulence generation in a vertical water tunnel and measurements of the turbulent flow this jet array establishes. The design of the array allows us to control the mean background flow and the turbulence intensity independently of each other. The array consists of a rectangular arrangement of 112 individually computer-controlled water jets that are aligned streamwise to the measurement section of our 8-m tall vertically recirculating water tunnel. Using solenoid valves, individual jets are activated following predefined protocols that can be tailored to obtain different turbulence statistics within the measurement section. The protocols are based on four-dimensional OpenSimplex noise, a type of gradient noise that features spatial and temporal coherence. Details of the mechanical and electrical designs are presented, together with a detailed description of the protocol generation. We show that the resulting turbulence is near homogeneous and isotropic, with a turbulence intensity of Order 1, an energy dissipation rate of order <span>(10^{-1},mathrm {m^2/s^3})</span> and <span>(textrm{Re}_{lambda }approx 1400)</span>. Additionally, we present experiments that show the effects that various system and protocol parameters have on the created flow conditions and address the streamwise development, as well as the homogeneity and isotropy of the flow.</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00348-025-04103-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145057580","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

Experimental study of competition between Rayleigh–Taylor and double-diffusive fingering when particles settle in the presence of a diffusing scalar in a Hele–Shaw cel1 Hele-Shaw细胞中粒子在扩散标量存在下沉降时瑞利-泰勒指法和双扩散指法之间竞争的实验研究

IF 2.5 3区工程技术

Experiments in Fluids Pub Date : 2025-09-11 DOI: 10.1007/s00348-025-04107-9

P. Bunton, D. Olsen, N. Konopliv, D. Stump, G. Thomas, E. Meiburg

{"title":"Experimental study of competition between Rayleigh–Taylor and double-diffusive fingering when particles settle in the presence of a diffusing scalar in a Hele–Shaw cel1","authors":"P. Bunton, D. Olsen, N. Konopliv, D. Stump, G. Thomas, E. Meiburg","doi":"10.1007/s00348-025-04107-9","DOIUrl":"10.1007/s00348-025-04107-9","url":null,"abstract":"<div><p>We investigate fluid instabilities in a Hele–Shaw cell driven by the combined effects of double diffusion (DD) and Rayleigh–Taylor (RT) mechanisms, focusing on the formation of vertical fingers and overturning plumes. These patterns emerge from the interplay between sediment settling and the diffusion of a scalar (dextrose). A novel experimental design is introduced in which particle sizes are selected so that their settling velocities are slower than, comparable to, or faster than the solute diffusion rate. This systematic variation allows the relative influence of settling and diffusion to be isolated and quantified. Two primary questions are addressed. First, under what conditions do fingering instabilities arise, as opposed to pure particle settling? We find that fingering is suppressed when the particle settling velocity exceeds the DD finger tip velocity. A predictive criterion is developed based on a dimensionless gravity parameter and the ratio of characteristic settling to diffusion times. Second, when instabilities are present, which mechanism—DD or RT—dominates? As expected, DD dominates when diffusion is rapid. A transition from DD to RT is observed when the settling-to-diffusion time ratio falls below approximately 0.2, using the gap width as the characteristic length scale. This work introduces a straightforward framework for exploring competing instability mechanisms in sediment-laden, diffusive flows in an experimentally accessible, previously uncharacterized parameter space.</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145028203","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

Exploring fluorescence lifetime potential for analyzing the composition of vaporizing bicomponent droplets 探索分析汽化双组分液滴组成的荧光寿命势

IF 2.5 3区工程技术

Experiments in Fluids Pub Date : 2025-09-10 DOI: 10.1007/s00348-025-04108-8

Minghao Wang, Mehdi Stiti, Hadrien Chaynes, Guillaume Castanet

{"title":"Exploring fluorescence lifetime potential for analyzing the composition of vaporizing bicomponent droplets","authors":"Minghao Wang, Mehdi Stiti, Hadrien Chaynes, Guillaume Castanet","doi":"10.1007/s00348-025-04108-8","DOIUrl":"10.1007/s00348-025-04108-8","url":null,"abstract":"<div><p>Predicting droplet evaporation is particularly complex when the liquid phase consists of multiple components. To date, only a limited number of physical optical phenomena have been used to non-intrusively measure the composition of droplets. Laser-induced fluorescence is a promising approach, as the emission and absorption of certain fluorescent dyes are known to depend on solvent polarity, viscosity, and, more generally, the chemical environment. However, a challenge is that fluorescence signal intensity is generally sensitive to both temperature and composition. This study investigates fluorescence lifetime measurements as a robust alternative. We demonstrate that, with a well-chosen fluorescent dye, it is possible to measure the composition of bicomponent droplets using a single dye and a single detection band, with minimal constraint on detection band selection, and without ambiguity due to temperature variations. To validate the technique, it is applied to acoustically levitated droplets across several mixtures that exhibit markedly different behaviors.</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 10","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00348-025-04108-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145021726","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

Elastic nozzles reduce the influence of pressure pulses on liquid jets 弹性喷嘴减小了压力脉冲对液体射流的影响

IF 2.5 3区工程技术

Experiments in Fluids Pub Date : 2025-09-05 DOI: 10.1007/s00348-025-04104-y

MD. Emazuddin Alif, Mackenzie Brogan, Fellah Mohsun, Christopher Williamson, Reagan Barr, Ria Corder, Andrew K. Dickerson

{"title":"Elastic nozzles reduce the influence of pressure pulses on liquid jets","authors":"MD. Emazuddin Alif, Mackenzie Brogan, Fellah Mohsun, Christopher Williamson, Reagan Barr, Ria Corder, Andrew K. Dickerson","doi":"10.1007/s00348-025-04104-y","DOIUrl":"10.1007/s00348-025-04104-y","url":null,"abstract":"<div><p>Nozzle characteristics modulate the stability of liquid jets, but their role in jet robustness to external disturbances is understudied. Here we produce jets with thin elastic membranes containing a hole of approximately 500 <span>(mu)</span>m in undeformed diameter. Our softest membranes produce the most stable jets in the Rayleigh and first wind-induced breakup regimes. An externally applied upstream pressure pulse lasting approximately 1 ms momentarily reduces the jet breakup distance and alters morphology. The pressure pulse is generated by the strike of a coil spring against a membrane mounted to the jet relaxation chamber. Softer nozzles and higher jet velocities minimize the disruption to the otherwise steady jet. Linear temporal theory for short nozzles derived using a dilated nozzle diameter well predicts breakup length before and after the pressure pulse. We propose hypothetical states for which our pressure pulse does not affect jet stability. Pressure disturbances initiate morphological changes in the jet, introducing novel phenomena like jet thinning and exit coalescence. Our results demonstrate that nozzle compliance can play a significant role in damping undesirable disturbances.</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 9","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144990396","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 investigation of flow and heat transfer characteristics in tandem cylinders at high wall temperatures 高温下串联式气缸流动与传热特性的实验研究

IF 2.5 3区工程技术

Experiments in Fluids Pub Date : 2025-09-01 DOI: 10.1007/s00348-025-04101-1

Shikang Chen, Dundian Gang, Yiding Gao

{"title":"Experimental investigation of flow and heat transfer characteristics in tandem cylinders at high wall temperatures","authors":"Shikang Chen, Dundian Gang, Yiding Gao","doi":"10.1007/s00348-025-04101-1","DOIUrl":"10.1007/s00348-025-04101-1","url":null,"abstract":"<div><p>The flow field around tandem heated cylinders is a subject of ongoing research due to its relevance in various engineering applications. This study investigates the influence of wall temperature and incoming flow velocity on the flow regime and heat transfer characteristics of tandem cylinders. Using a combined technique of Schlieren imaging and particle image velocimetry (PIV), the flow field was characterized over a range of incoming flow velocities (0.4 to 0.9 m/s) and cylindrical wall temperatures (423 to 673 K). The results indicate that higher wall temperatures promote a transition from the co-shedding regime to the shear layer reattachment regime. Conversely, increasing the incoming flow velocity leads to a transition from the shear layer reattachment regime back to the co-shedding regime. Beyond the flow regimes, the convective heat transfer was also quantified in the study, and a strong positive correlation was found between both wall temperature and incoming flow velocity and the convective heat transfer coefficient. These results demonstrate the significant influence of thermal and velocity conditions on the flow behavior and heat transfer in tandem cylinder arrangements.</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 9","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144927083","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

On the interaction of a linear plug nozzle flow with sub-, trans-, and supersonic outer flow 线性塞式喷嘴流动与亚、反、超声速外流的相互作用

IF 2.5 3区工程技术

Experiments in Fluids Pub Date : 2025-08-31 DOI: 10.1007/s00348-025-04098-7

Paul Wißmann, Christian J. Kähler, Sven Scharnowski

{"title":"On the interaction of a linear plug nozzle flow with sub-, trans-, and supersonic outer flow","authors":"Paul Wißmann, Christian J. Kähler, Sven Scharnowski","doi":"10.1007/s00348-025-04098-7","DOIUrl":"10.1007/s00348-025-04098-7","url":null,"abstract":"<div><p>A plug/aerospike nozzle is a promising concept as a propulsion system for space launchers and space planes. The inherent ability to adapt the nozzle jet to the ambient pressure level improves the thrust performance under overexpanded operating conditions compared to conventional bell nozzles, which is of great interest for future single-stage-to-orbit vehicles. This experimental study investigates the topology and aerodynamics of a cold flow linear plug nozzle jet in an outer flow environment. PIV and high-speed schlieren measurements are utilized to understand the mutual aerodynamic interaction between each other. The jet flow is studied for a variety of nozzle pressure ratios in combination with an outer flow at sub-, trans-, and supersonic Mach numbers. The flow is examined for two plug lengths, which are 72% and 24% of an ideal contour. It is found that the combination of nozzle pressure ratio and outer Mach number strongly influences the flow pattern and local velocity magnitudes. Backflow regions are measured, mainly emerging through the integration of the nozzle in a bluff aft body. The strength and frequency of aerodynamic modes are found to be highly dependent on the operating conditions as well. The most relevant ones are jet screeching, alternating vortex shedding of the outer flow, and vortex shedding in the base wake of the plug with strong truncation. The latter causes strong fluctuations in the flow, which are transmitted to the shear layer and induce acoustic wave emission. In addition, the flow locally accelerating in the plug base region results in increased shock strength in the jet structure. At trans- and supersonic outer flow, however, the aerodynamic modes of the jet flow are strongly suppressed. The impact of plug truncation on the velocity field becomes less for higher nozzle pressure ratios and outer flow Mach numbers.</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 9","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00348-025-04098-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144923350","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

An investigation of the major characteristics of surface pressure fields beneath two types of tornado-like vortices and their causes 两种类龙卷风涡旋下地表压力场的主要特征及其成因的研究

IF 2.5 3区工程技术

Experiments in Fluids Pub Date : 2025-08-28 DOI: 10.1007/s00348-025-04099-6

Zhuo Tang, Qiang Chen, Xinyang Wu, Darryl L. James, Delong Zuo

{"title":"An investigation of the major characteristics of surface pressure fields beneath two types of tornado-like vortices and their causes","authors":"Zhuo Tang, Qiang Chen, Xinyang Wu, Darryl L. James, Delong Zuo","doi":"10.1007/s00348-025-04099-6","DOIUrl":"10.1007/s00348-025-04099-6","url":null,"abstract":"<div><p>A series of experiments were performed in a tornado simulator to study tornado-like vortices, with a focus on the surface pressure fields beneath the vortices. In the experiments, the pressures on the floor beneath a single-celled vortex and a two-celled vortex were measured. The measurements were used to characterize the surface pressure fields, which revealed, among others, the spatially varying non-Gaussian distribution of the surface pressures, the existence of narrowband components in the pressure fluctuations, and the differences between the characteristics of the surface pressure fields beneath the two types of vortices. A further analysis of the time and spatial variations of the surface pressure fields enabled the identification of the phenomena that cause these major characteristics of the surface pressure fields and the specific differences in these phenomena that result in the differences in the characteristics of the surface pressure fields beneath the two types of vortices. The findings from the study of the surface pressure fields provided insights into the nature of the tornado-like vortices aloft.</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"66 9","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00348-025-04099-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144909790","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

Determination of aerodynamic forces using PIV velocity fields 利用PIV速度场测定气动力

IF 2.5 3区工程技术

Experiments in Fluids Pub Date : 2025-08-12 DOI: 10.1007/s00348-025-04096-9

Colin Stutz, Samuel Rovani, Douglas Bohl, John Hrynuk

{"title":"Determination of aerodynamic forces using PIV velocity fields","authors":"Colin Stutz, Samuel Rovani, Douglas Bohl, John Hrynuk","doi":"10.1007/s00348-025-04096-9","DOIUrl":"10.1007/s00348-025-04096-9","url":null,"abstract":"<div><p>Traditional methods for directly measuring aerodynamic forces are particularly challenging at low Reynolds numbers due to the low dynamic pressures. This becomes even more challenging when rapid motions of the test articles are present, with inertial forces often larger than the aerodynamic forces. Existing methods for calculating pressure fields from experimental vector fields, such as those measured using particle image velocimetry (PIV), have constraints that make them difficult or impossible to apply to data sets that do not meet certain conditions, such as boundary condition requirements or restrictions on the grid shape of the data. This paper describes a new method of determining surface pressures and aerodynamic forces using experimentally collected velocity field data. This method leverages field erosion to constrain a point-stepping spatial integration of the pressure gradient field. A systematic method for dividing the flow field into zones based on the vorticity of the flow and the known geometry of the experiment allows for pressure in less-disturbed portions of the flow to be calculated and used as the boundary conditions for more unsteady flow regions. Surface pressures are then extracted from on or near the surface and integrated to calculate lift and drag. Two data sets are used as validation cases: a pitch-and-hold dynamic stall and static lift around an airfoil, both at low Reynolds number. The pressure-derived lift curves compare favorably with the reference data sets, demonstrating the accuracy of the new method.</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":"144832070","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

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