Experimental Thermal and Fluid Science最新文献

{"title":"Investigation into the bag breakup and sub-droplet size distribution of tandem water droplet pair in an elevated-temperatures continuous airflow","authors":"Ke Zheng ,&nbsp;Yufei Zhu ,&nbsp;Zhiwen Gan","doi":"10.1016/j.expthermflusci.2025.111625","DOIUrl":"10.1016/j.expthermflusci.2025.111625","url":null,"abstract":"<div><div>Understanding droplet interaction mechanisms in dense sprays requires investigation of tandem droplet pair fragmentation. This investigation uses a high-speed camera to examine the fragmentation phenomena and sub-droplet distribution of tandem water droplet pair with separation distances (<em>S</em>) ranging from 1.9 to 13.3 under airflow temperatures between 293 K and 493 K. The separation distance is the ratio of the actual spacing to the droplet diameter. Within a critical separation distance, the bag breakup of the lead droplet is influenced by collision with the trailing droplet. The critical separation distance for the lead droplet bag breakup decreases with airflow temperature. Separation distance and airflow temperature influence the trailing droplet bag breakup through the collision with the lead droplet, the lead droplet shielding effect, and the airflow velocity dissipation. Further, the sub-droplet size distribution of the broken lead droplet is analyzed by dividing the broken droplet into three parts: bag, rim, and node. The correlation length governing the bag sub-droplet size primarily depends on the bag thickness, while the rim and node sub-droplet sizes depend on the liquid ring thickness. Separation distance and airflow temperature affect the sub-droplet size distributions by altering the volume fractions of the bag, rim, and node, as well as their correlation lengths. A semi-empirical model for predicting the Sauter mean diameter (SMD) of the sub-droplet of the broken lead droplet is proposed based on the volume fractions of different parts (bag, rim, and node) and their correlation lengths. The predictions align well with the experimental data among across a wide range in this investigation. This investigation can provide experimental data and theoretical references for understanding the droplet interaction mechanisms within dense sprays.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"171 ","pages":"Article 111625"},"PeriodicalIF":3.3,"publicationDate":"2025-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145267861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental study on cavitation pattern and near-field spray characteristics of methanol in the scaled-up fuel injection nozzle","authors":"Wei Huang ,&nbsp;Yizhou Yang ,&nbsp;Zhixia He ,&nbsp;Zhen Yang ,&nbsp;Shengnan Zhang ,&nbsp;Yuanfeng Zhao ,&nbsp;Wei Guan ,&nbsp;Genmiao Guo","doi":"10.1016/j.expthermflusci.2025.111624","DOIUrl":"10.1016/j.expthermflusci.2025.111624","url":null,"abstract":"<div><div>Methanol, as a clean fuel, particularly when synthesized from green electricity and recycled CO₂, has zero-carbon potential and is gaining increasing attention. However, due to methanol’s corrosivity and unique physical properties, designing high-pressure injectors for methanol engines presents numerous challenges. This study presents the first comprehensive analysis of methanol’s flow characteristics and near-field spray behavior using a scaled-up optical nozzle. Rounded and sharp nozzles were used to investigate vortex-induced string cavitation and geometry-induced sheet cavitation. By adjusting the needle lift and injection pressure, the onset and development of various cavitation patterns in methanol were studied. Additionally, comparative experiments between methanol and diesel were conducted to analyze the differences in flow and spray characteristics under different cavitation regimes, providing insights for the use of methanol as a replacement for diesel in engines. Experimental results show that methanol’s lower viscosity promotes the exsolution of dissolved gases, forming free gas bubbles that accumulate in the vortex core, thereby enhancing string cavitation. Under identical operating conditions, methanol exhibits a stronger tendency for string cavitation and greater cavitation intensity compared to diesel. In contrast, the difference in geometric-induced cavitation intensity between methanol and diesel is relatively small, attributed to methanol’s less sensitive response to variations in fuel properties.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"171 ","pages":"Article 111624"},"PeriodicalIF":3.3,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measurement of dissimilar destruction of turbulent momentum and heat fluxes without instantaneous pressure acquisition","authors":"Toru Mukai,&nbsp;Mamoru Takahashi,&nbsp;Komei Fujikura,&nbsp;Koichi Tsujimoto,&nbsp;Toshitake Ando","doi":"10.1016/j.expthermflusci.2025.111621","DOIUrl":"10.1016/j.expthermflusci.2025.111621","url":null,"abstract":"<div><div>Pressure–rate-of-strain and pressure–temperature-gradient statistically contribute to the destruction of turbulent momentum and heat fluxes, respectively. However, in instantaneous fields, both forward (loss) and backward (gain) destruction events can occur. Moreover, dissimilar destruction of turbulent fluxes, such as the forward destruction of momentum flux and backward destruction of heat flux, and vice versa, can arise in shear flows. In this study, we experimentally quantify the dissimilarity of turbulent fluxes in a heated round jet. The destruction of the turbulent fluxes is governed by the pressure-rate-of-strain for the momentum flux and the pressure-temperature-gradient of the heat flux. To circumvent the need for instantaneous pressure fluctuation measurements, we employed a combined probe consisting of an X-type hot-wire and two parallel cold-wire sensors. This setup enabled the quantification of the fraction of total events corresponding to dissimilar flux destruction. The combined probe provided accurate velocity and temperature statistics, including their derivatives, except in the outer regions of the jet, where the mean velocity is extremely small. Furthermore, confidence in measuring intermediate-scale fluctuations, which are related to the destruction of turbulent fluxes, is confirmed. Finally, the joint statistics between the velocity and temperature derivatives indicate that the destruction of turbulent fluxes in a free round jet is highly dissimilar. We find that the coherence of the destruction of turbulent fluxes due to intermediate-scale fluctuations is at most 0.4 and decreases with the streamwise distance from the exit and increasing frequency. Furthermore, approximately half of the instantaneous events exhibit dissimilar destruction of the turbulent fluxes.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"171 ","pages":"Article 111621"},"PeriodicalIF":3.3,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Swirling flow and spray atomization interactions in a swirl cup airblast fuel injector: Venturi outlet angle","authors":"Yushuai Liu ,&nbsp;Chuanyu Fang ,&nbsp;Shaolin Wang ,&nbsp;Cunxi Liu ,&nbsp;Yong Mu ,&nbsp;Gang Xu","doi":"10.1016/j.expthermflusci.2025.111622","DOIUrl":"10.1016/j.expthermflusci.2025.111622","url":null,"abstract":"<div><div>Swirl cup airblast fuel injectors are critical components in modern low-emission gas turbine combustors. Understanding the underlying physics of the interaction between fuel spray and complex swirling airflow is crucial for optimizing injector performance. This study investigates the influence of Venturi outlet angles (15°, 25°, and 35°) on airflow field and spray atomization dynamics. Advanced optical diagnostics, including high-speed shadowgraph, Phase Doppler Particle Analyzer (PDPA), Particle Imaging Velocimetry (PIV), and Planar Mie scattering (PMie), were employed to quantify flow-spray interactions under controlled fuel flow rates (2.0–4.0 kg/h) and 3 % relative air pressure drop. Results demonstrate that the Venturi outlet angle significantly modulates primary atomization. Increasing the angle from 15° to 35° reduces liquid film length by 69.2 % due to enhanced gas–liquid shear stress. Moreover, larger angles amplify central toroidal recirculation zone (CTRZ) reverse velocity (−1.2 to −6.8 m/s), intensifying droplet entrainment and reducing Sauter Mean Diameter (SMD) by 30.9 %. These findings highlight that Venturi angles &gt; 25° optimize atomization by balancing shear-driven breakup and recirculation-enhanced mixing, providing critical insights for designing fuel injectors with improved combustion stability and emission performance.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"171 ","pages":"Article 111622"},"PeriodicalIF":3.3,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on the microscopic characteristics of successive droplet clusters impacting on the wall","authors":"Feixiang Chang ,&nbsp;Mang Yan ,&nbsp;Hongliang Luo ,&nbsp;Wuli Hong ,&nbsp;Yewen Feng ,&nbsp;Fei Liu ,&nbsp;Chang Zhai ,&nbsp;Kang Yang ,&nbsp;Bo Song ,&nbsp;Jian Zhang ,&nbsp;Samir Chandra Ray","doi":"10.1016/j.expthermflusci.2025.111619","DOIUrl":"10.1016/j.expthermflusci.2025.111619","url":null,"abstract":"<div><div>In Direct Injection Spark Ignition (DISI) internal combustion engines, fuel droplets inevitably impact the cylinder walls, resulting in droplet adhesion and incomplete combustion, thereby increasing pollutant emissions. The injection strategy has been proven to significantly improve the droplet-wall interaction. Initially, the Refractive Index Matching (RIM) method was used to measure fuel adhesion under both single and double injection conditions, with results confirming that the double injection strategy significantly reduced the fuel adhesion mass. To investigate the mechanisms underlying the reduction in fuel adhesion with double injection, Particle image analysis (PIA) and a multiple droplets producer were employed to examine the micro-behavior of successive droplet clusters near the wall surface. Statistical analyses were conducted on droplet size and velocity. Results showed that, when the two successive droplet clusters impact the wall, the Sauter Mean Diameter (SMD) of the second cluster is greater than that of the first cluster. There are two reasons for this. First, this difference is attributed to the coalescence between the leading droplets of the second droplet cluster and the trailing droplets of the first droplet cluster. Second, when the second droplet cluster impacts the wall, the breakup of fuel adhesion can also lead to the formation of larger droplets. Moreover, the second droplet cluster exhibits a significantly higher penetration velocity than that of the first, which can be attributed to the interaction of the velocity fields between the trailing droplets of the first cluster and the leading droplets of the second cluster. Furthermore, analysis of the average minimum droplet distance shows that droplet number density near the wall is relatively high and decreases with increasing distance from the wall. Lastly, the Bai model was used to predict the probabilities of stick, rebound, spread, and splash of successive droplet clusters at various observation points.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"171 ","pages":"Article 111619"},"PeriodicalIF":3.3,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of stratification on thermoacoustic instability, emissions, and flame macrostructure in a swirl-stabilized dual annular burner: An experimental study","authors":"Qazi Talal ,&nbsp;Zubairu Abubakar ,&nbsp;Ahmed Gaber H. Saif ,&nbsp;ELSaeed Saad ELSihy ,&nbsp;M. Raghib Shakeel ,&nbsp;Esmail M.A. Mokheimer","doi":"10.1016/j.expthermflusci.2025.111620","DOIUrl":"10.1016/j.expthermflusci.2025.111620","url":null,"abstract":"<div><div>Stratified flames have attracted significant attention due to their superior resilience to turbulence and enhanced flame stability, enabling reduced NO_x and CO emissions. In this study, an innovative dual annular stratified burner was designed and experimentally investigated to characterize thermoacoustic instability, emissions and flame macrostructure in swirling and non-swirling (jet) methane-air flames. Experiments were systematically conducted across stratification ratios (SR = 1–3) and global equivalence ratios (Φ_g) ranging from lean blowoff to rich conditions (Φ_g = 1.2). Swirling flames exhibited consistently acceptable emissions (NO_x and CO &lt; 20 ppm) under stable lean operating conditions (Φ_g = 0.55–0.8) for all SRs tested. Jet flames showed no thermoacoustic instabilities irrespective of SR or Φ_g variations. Similarly, swirling flames remained stable for Φ_g &lt; 0.8; however, at Φ_g = 0.8, thermoacoustic instability initiated, characterized by coupled oscillations of acoustic pressure and heat release fluctuations. These oscillations were sustained until Φ_g = 1.1, beyond which decoupling occurred. Limit cycle oscillations with heightened sound pressure amplitudes were observed at lower stratification ratios (SR = 1–1.5), whereas no limit cycles were detected at higher SR values (&gt;1.5). Increasing SR significantly suppressed instability amplitudes, notably resulting in a 70 % reduction of oscillation amplitudes at Φ_g = 0.9 when SR increased from 1 to 3. Flame macrostructure analysis confirmed improved anchoring and mixing characteristics of swirling flames compared to jet flames, particularly at higher SR conditions. This work highlights that controlled stratification effectively enhances operational stability and produces more compact flames in swirling combustors, offering valuable insights for developing low-emission and high-efficiency combustion systems.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"171 ","pages":"Article 111620"},"PeriodicalIF":3.3,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An experimental investigation of transient ice accretion process on a high-lift airfoil model for UAV applications","authors":"Manaf Muhammed ,&nbsp;Anvesh Dhulipalla ,&nbsp;Harsha Sista ,&nbsp;Hassan A. Khawaja ,&nbsp;Muhammad S. Virk ,&nbsp;Hui Hu","doi":"10.1016/j.expthermflusci.2025.111612","DOIUrl":"10.1016/j.expthermflusci.2025.111612","url":null,"abstract":"<div><div>An experimental study is performed to investigate the transient ice accretion process along the surface of a high-lift, S1223 airfoil model, and the icing-induced aerodynamic performance degradation. The UAV airfoil model was exposed to typically glaze and rime icing conditions encountered by UAVs flying in low-altitude airspace. While the rime ice accretion was found to conform with the original profile of the UAV airfoil model well in general, substantial “feather-like” ice roughness elements were observed to grow rapidly over both the suction-side and pressure-side surfaces near the airfoil leading edge. The glaze ice accretion process was featured by obvious wind-driven water runback to transport the unfrozen water mass from the airfoil frontal surface to further downstream locations, causing the formation of complex rivulet-shaped ice structures and growth of ice “horns” along the leading edge and “finger-liked icicles” near the trailing edge. The aerodynamic performance of the UAV airfoil was found to degrade continuously with the increasing ice accretion time. The ice accretion over a period of 463 s was found to reduce UAV endurance from 18% to 46 % and diminish the UAV flying range by 13 % to 40 %, depending on the nature of ice accreted. The acquired ice accretion images were coordinated with the aerodynamic force measurements to gain further insight into the underlying physics for a better understanding of the UAV inflight icing phenomena.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"171 ","pages":"Article 111612"},"PeriodicalIF":3.3,"publicationDate":"2025-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Wake behavior and entrainment motion in the far-field stage of over-tripped boundary layer turbulence","authors":"Letian Chen ,&nbsp;Zhanqi Tang ,&nbsp;Zhenqing Li ,&nbsp;Nan Jiang","doi":"10.1016/j.expthermflusci.2025.111617","DOIUrl":"10.1016/j.expthermflusci.2025.111617","url":null,"abstract":"<div><div>This study investigates the far-field wake behavior and entrainment motions of the over-tripped boundary layer (OT-BL) turbulence induced by a family of wall-mounted tripwires with different wall blockage rate <span><math><mrow><msub><mi>σ</mi><mi>w</mi></msub></mrow></math></span>. Friction Reynolds number <span><math><mrow><msub><mrow><mi>Re</mi></mrow><mi>τ</mi></msub></mrow></math></span> is more than twice that of the unperturbed canonical turbulent boundary layer. Far-field streamwise development of the OT-BL is referred to as a cooperative action of wall-driven and wake-driven mechanisms. Spatial two-point correlation and intermittency factor are employed to quantify the wall-driven and wake-driven ranges. The wall driver shows a weak dependence on the tripwire configuration, whereas the wake driver is clearly related to the tripwire configuration. Along with downstream development, the wake-driven region exhibits an upward and spreading trend, which correlates positively with <span><math><mrow><msub><mi>σ</mi><mi>w</mi></msub></mrow></math></span> of tripwires. The wake dynamics in turbulent region and near-interface region are revealed from the turbulent/non-turbulent interface perspective. In the upstream stage, the wake is controlled by the tripwire-excited disturbed eddies, and then, in the downstream stage, the near-interface wake dynamics are gradually similar to canonical pattern. Further, entrainment is considered based on nibbling and engulfing motions. For OT-BL, tripwire-excited disturbed eddies enhance nibbling and engulfing entrainment. Nibbling entrainment is the main entrainment mode, although engulfing process is also a significant component. Finally, the study assesses the far-field recovery trend of the OT-BLs’ wake dynamics and entrainment motion. This research provides a reference for tripwire design to simulate higher-<span><math><mrow><msub><mrow><mi>Re</mi></mrow><mi>τ</mi></msub></mrow></math></span> OT-BL in a finite test section. Meanwhile, we discuss the evaluation scheme on the wake turbulence characteristics of OT-BL from multiple perspectives.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"171 ","pages":"Article 111617"},"PeriodicalIF":3.3,"publicationDate":"2025-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-speed impact of water droplets on microtextured surfaces: Effect of roughness and wettability on corona splashing","authors":"Danila Verkhodanov ,&nbsp;Nikita Khomutov ,&nbsp;Maxim Piskunov ,&nbsp;Ivan Vozhakov ,&nbsp;Sergey Starinskiy ,&nbsp;Alexey Safonov ,&nbsp;Nikita Smirnov","doi":"10.1016/j.expthermflusci.2025.111618","DOIUrl":"10.1016/j.expthermflusci.2025.111618","url":null,"abstract":"<div><div>A study of the high-speed impact of water droplets on smooth and microtextured fluoropolymer-coated titanium surfaces is presented. The experimental samples had an average roughness <em>R_a</em> from 0.04 μm to 15.4 μm and a static contact angle <em>θ</em> from 74° to 164°. The 0.5–1.3-mm droplets were impacted on the surfaces at velocities <em>U₀</em> = 5–20 m/s (the Weber number <em>We</em> = 450–2,800). Using a high-speed video camera with a sample rate of 60,000 frames per second, the values of the opening angle <em>α</em>, the maximum diameter <em>D_cor</em>, and the lifetime of the corona were measured and analyzed. In addition, the mean splashing velocities of both large and small secondary fragments were captured. A dimensionless ratio, <em>α/θ</em>, which characterizes the predominance of inertial or adhesive forces, was proposed for the development of an empirical model for predicting <em>D_cor</em>. This model was validated using data from other authors, which proved its applicability in the ranges of <em>We</em> = 450–2,800, <em>R_a</em> = 1.05–38 µm, <em>θ</em> = 69–164° (water) and <em>θ</em> <span><math><mo>≈</mo></math></span> 0° (ethanol). The research elucidated that superhydrophobic microtextured surfaces provide greater symmetry in corona splash and a larger opening angle. However, these surfaces also delayed liquid removal during splashing, which has the potential to impact the effectiveness of their water-repellent properties.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"171 ","pages":"Article 111618"},"PeriodicalIF":3.3,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Flow and wave characteristics of jet drainage film under crossflow","authors":"Qiuxiang Chen,&nbsp;Xinying Wang,&nbsp;Qiang Li,&nbsp;Hongfei Hu,&nbsp;Haijun Wang","doi":"10.1016/j.expthermflusci.2025.111616","DOIUrl":"10.1016/j.expthermflusci.2025.111616","url":null,"abstract":"<div><div>The interaction between jet drainage films and crossflow is widespread in engineering systems such as liquid rocket engines and nuclear reactor emergency cooling systems. In these processes, an understanding of the flow behavior and fluctuation characteristics of drainage films under crossflow is essential. In this study, an experimental system was constructed to investigate the behavior of jet drainage films under crossflow. The spatial evolution of film offset, average film thickness, base film thickness, wave height, and fluctuation characteristics was investigated under varying crossflow velocities using high-speed imaging and spectral confocal measurement techniques. The results show that the drainage film is shifted to the crossflow direction, and the offset increases linearly with the flow distance, which is inversely proportional to the jet Weber number and directly proportional to the crossflow Weber number. The spatial distribution characteristics of the average liquid film thickness, base film thickness, and wave height are jointly influenced by the jet Weber number and crossflow velocity. The cross-sectional averages of liquid film thickness, base film thickness, and wave height exhibit an initial decrease followed by a subsequent increase with flow distance. The standard deviation of the liquid film thickness was significantly and linearly correlated with its average value, with a slope of approximately 0.3. As the crossflow velocity increases, the liquid film fluctuations on the leeward side of the drainage film are significantly suppressed at low jet Weber numbers, while the liquid film fluctuations on the windward side are notably weakened at the high jet Weber number.</div></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":"171 ","pages":"Article 111616"},"PeriodicalIF":3.3,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145047489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}