International Journal of Multiphase Flow最新文献

{"title":"Impact of water droplet on oil films suspended over water bath: Crater and jet dynamics","authors":"Xiaolong He ,&nbsp;Qian Yang ,&nbsp;Haonan Peng ,&nbsp;Linlin Fei ,&nbsp;Jianmin Zhang ,&nbsp;Ya-Ling He","doi":"10.1016/j.ijmultiphaseflow.2026.105644","DOIUrl":"10.1016/j.ijmultiphaseflow.2026.105644","url":null,"abstract":"<div><div>The water droplet impact dynamics on an oil film over the water bath are studied based on extensive experiments, with a focus on the effects of key parameters (droplet size, impact velocity, and oil-film thickness) on the crater growth and the jet formation. A multi-interfaces theory, considering the surface-energy variations of the deformed droplet–air, oil–droplet, and oil–water interfaces, is proposed to describe the total change in the surface energy during the impact, leading to an effective surface tension and Weber number for the following analysis. The maximum crater depth follows a scaling <span><math><mrow><msubsup><mi>d</mi><mi>e</mi><mo>′</mo></msubsup><mo>∼</mo><mrow><mo>(</mo><mrow><mi>F</mi><msup><mrow><mi>r</mi></mrow><mrow><mn>1</mn><mo>/</mo><mn>4</mn></mrow></msup><mo>/</mo><msup><mi>ρ</mi><mo>′</mo></msup></mrow><mo>)</mo></mrow></mrow></math></span>, consistent with classical theory, although the crater depth is slightly overestimated for thick oil films due to an underestimation of viscous dissipation. The total crater energy accounts for approximately 27∼35% of the initial droplet impact energy for<span><math><mrow><mrow><mspace></mspace><mtext>Fr</mtext></mrow><mo>≥</mo><mn>100</mn></mrow></math></span>. Furthermore, the maximum jet length scales as <span><math><mrow><msup><mi>l</mi><mo>′</mo></msup><mo>∼</mo><mtext>We</mtext></mrow></math></span>, with jet pinch-off occurring when <span><math><mrow><msup><mi>l</mi><mo>′</mo></msup><mfrac><mo>&gt;</mo><mstyle><mo>∼</mo></mstyle></mfrac><mn>1.24</mn></mrow></math></span>, demonstrating the capability of the proposed multi-interfaces theory to capture crater and jet dynamics. The measured maximum jet length also falls into the classical scaling relationship with the effective Weber number. Finally, two main impact regimes are identified using the effective Weber number <span><math><mrow><mi>W</mi><msub><mi>e</mi><mrow><mi>e</mi><mo>_</mo><mi>h</mi></mrow></msub></mrow></math></span> in combination with the product of the Reynolds and Froude numbers <span><math><mrow><mi>R</mi><mi>e</mi><mi>F</mi><msub><mi>r</mi><mi>h</mi></msub></mrow></math></span>. Generally, the developed multi-interface theory can correctly estimate the effect of the oil layer on the impact dynamics.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"198 ","pages":"Article 105644"},"PeriodicalIF":3.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146186567","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":"A mechanical model for the mixed-size particle splash process based on the stochastic particle-bed collision","authors":"Junqing Lei ,&nbsp;Guohua Wang ,&nbsp;Xiaojing Zheng","doi":"10.1016/j.ijmultiphaseflow.2026.105641","DOIUrl":"10.1016/j.ijmultiphaseflow.2026.105641","url":null,"abstract":"<div><div>Investigating the interaction between sand particles and an erodible bed is fundamental to understanding wind-blown sand saltation. Since natural sand beds consist of non-uniformly distributed mixed-size particles, the existing three-particle stochastic granular-bed collision model (TPSGCM) for single-size particles is insufficient. To address this, the present study has developed a mixed-size four-particle stochastic granular-bed collision model (FPSGCM) that incorporates the shielding effect. This effect is influenced by the relative size of the impacted and shielding particles, as well as their relative vertical position. The new FPSGCM accurately reproduces the splash process of mixed-size particles. When applied to simulate wind-blown sand flow, the model predictions for the sand transport rate, saltation length, and height are in better agreement with experimental and theoretical results.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"198 ","pages":"Article 105641"},"PeriodicalIF":3.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116565","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":"Numerical simulation on the coupling characteristics of air gun array bubbles","authors":"Shuna Wang ,&nbsp;Niannian Liu ,&nbsp;Shuai Zhang ,&nbsp;Hang Geng","doi":"10.1016/j.ijmultiphaseflow.2026.105643","DOIUrl":"10.1016/j.ijmultiphaseflow.2026.105643","url":null,"abstract":"<div><div>To investigate the underlying relationship between the mechanical structure of an air gun and its bubble pulsation, we developed a compressible jet-based model for air gun bubble dynamics using the computational fluid dynamics (CFD) software STAR-CCM+. This model facilitated a systematic analysis of the coupling characteristics of high-pressure air gun bubble arrays and the propagation patterns of pressure waves in their flow fields. By examining the air discharge process of air gun, the influence of its mechanical structure on the surrounding hydrodynamics was revealed. The results indicate that during the bubble collapse phase, a centripetal jet, accompanied by a high-pressure stagnation point, typically forms near the opening outside the air gun array. The study further demonstrates that a smaller inter-gun spacing leads to a longer bubble pulsation period, while the maximum bubble volume remains largely unchanged. A higher initial internal pressure results in an increased maximum bubble volume, a longer pulsation period, and a faster pressure wave propagation speed. Finally, the opening height was found to exert a significant influence on bubble pulsation when it falls outside a specific optimal range.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"198 ","pages":"Article 105643"},"PeriodicalIF":3.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146186566","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":"Mechanisms of Interfacial Evolution in Droplet Impact on Superhydrophobic Cones","authors":"Xiaofei Hu ,&nbsp;Bing Zhu ,&nbsp;Mingyang Lv ,&nbsp;Wei Zhang","doi":"10.1016/j.ijmultiphaseflow.2026.105637","DOIUrl":"10.1016/j.ijmultiphaseflow.2026.105637","url":null,"abstract":"<div><div>Droplet impact on conical surfaces is relevant to both natural processes and industrial applications. This study examines the interfacial evolution of droplets impacting superhydrophobic cones through experiments, simulations, and theoretical analysis, focusing on the effects of Weber number and cone angle. Four distinct impact modes are identified: (I) complete rebound without penetration; (II) penetration with ring formation and complete rebound; (III) penetration with ring formation followed by breakup during retraction; and (IV) penetration with ring formation followed by breakup during spreading. Increasing Weber number enhances the maximum spreading factor and prolongs spreading time, while larger cone angles suppress spreading and reduce the corresponding time. For non-penetration cases (Mode I), a pancake-like theoretical model based on energy conservation accurately predicts the maximum spreading factor. Mechanistically, Modes I–II arise from the balance of inertia and surface tension, Mode III from Rayleigh–Plateau instability, and Mode IV from local necking-induced ring rupture.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"198 ","pages":"Article 105637"},"PeriodicalIF":3.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116564","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":"Fall and fingering of miscible magnetic fluid drops in a Hele-Shaw cell","authors":"M.S. Krakov ,&nbsp;A.V. Chernyshov ,&nbsp;A.R. Zakinyan","doi":"10.1016/j.ijmultiphaseflow.2026.105639","DOIUrl":"10.1016/j.ijmultiphaseflow.2026.105639","url":null,"abstract":"<div><div>The presented study is the experimental and numerical investigation of the fall and fingering of miscible magnetic fluid drops with variable properties in a vertical Hele-Shaw cell under a uniform field normal to the cell plane. We revealed that fingering is possible in magnetic fields that exceed the critical value. For the kerosene-based magnetic fluid used in the experiment and a droplet with a radius of about 3 mm, the critical value of the magnetic field strength was about 2 kA/m. It was found numerically that the distance between the fingers is linearly related to the width of the gap in the Hele-Shaw cell, and for the studied cases it is described by the expression λ = 1.19δ for the magnetic field of about 15 kA/m. The distance between the fingers decreases with the increase of the magnetic field in the region of weak magnetic fields, and with a further increase of the magnetic field, it hardly changes. The velocity of the droplet fall is determined by its morphology. With an increase in the number of fingers, the velocity of the fall decreases significantly. With the maximum value of the parameters numerically studied, the fall velocity decreased 2.5 times. As the number of fingers increases, the rate of mixing of magnetic fluid with the environment increases sharply. During the drop-fall time, the maximum concentration of magnetic fluid decreased 4 times at the maximum value of the parameters studied. However, in the absence of a magnetic field, without fingering, it remained practically unchanged.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"198 ","pages":"Article 105639"},"PeriodicalIF":3.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146186569","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":"Numerical study on cavitation characteristics and flow field instability in a butterfly valve under choked conditions","authors":"Guang Zhang ,&nbsp;Shuqin Qi ,&nbsp;Zuchao Zhu ,&nbsp;Yuanming Ding ,&nbsp;Zhe Lin","doi":"10.1016/j.ijmultiphaseflow.2026.105647","DOIUrl":"10.1016/j.ijmultiphaseflow.2026.105647","url":null,"abstract":"<div><div>Under operating conditions with high pressure difference, the occurrence of choked cavitation may be observed in the valve, which differs from conventional cavitation behavior. Choked cavitation not only leads to flow saturation but is also accompanied by intense bubble growth and pressure fluctuation, posing threats to valve performance and service life. This study focused the flow characteristics of a butterfly valve under various opening degrees and pressure difference. Numerical analysis was conducted on the variations in mass flow rate, cavitation bubble distribution, local energy loss, and entropy production during the development of choked cavitation, with particular emphasis on identifying the critical transition region from normal flow to the choked-cavitation regime. Additionally, the relationship between cavitation morphology and energy characteristics at different opening degrees was examined. The results indicate that as the pressure difference increases, the flow undergoes successive stages: normal flow, choked transition and cavitation-induced choking. At 80 % opening degree, the energy loss and recovery processes are more symmetrical, indicating a more stable flow structure. In contrast, at the 40 % opening degree, a stronger throttling effect and asymmetric energy distribution are present, the cavitation cloud exhibits a shorter trailing region, resulting in more localized flow-field disturbances. Energy loss at 40 % opening degree is highly concentrated at the throat throttling zone, whereas at 80 % opening degree, the primary energy loss shifts downstream to the wake region dominated by the shedding and collapse of the cavitation cloud.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"198 ","pages":"Article 105647"},"PeriodicalIF":3.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146186581","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":"Simulations of bubble entrapment during receding in drop impact onto hydrophobic surfaces","authors":"Mingguang Shen ,&nbsp;Ben Q. Li","doi":"10.1016/j.ijmultiphaseflow.2026.105636","DOIUrl":"10.1016/j.ijmultiphaseflow.2026.105636","url":null,"abstract":"<div><div>Air entrapment is intriguing but not fully understood in drop impact problems. Generally, there are two kinds of air entrapment, one occurring in the early stage of spreading and the other in the receding stage. The first kind has been studied extensively, with consensus achieved on its formation mechanism. However, there has been little consensus on the second kind. This paper simulates the air entrapment of the second kind using a diffuse interface method. The established model is solved using a finite difference method on a half-staggered grid. The model was compared with an experiment, showing a reasonable agreement. The detailed trapping process was captured. Moreover, the effects of drop size and impact velocity were examined. It is found that for an air bubble to be trapped in the receding stage, the central air cavity should come into contact with the substrate. The bubble is then trapped due to the closing of the cavity. With increased drop sizes, air entrapment is more likely to happen. With increased impact velocities, the chance of entrapment is increased as well.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"198 ","pages":"Article 105636"},"PeriodicalIF":3.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146186578","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":"Revealing the effective basal condition of geophysical granular flows","authors":"Alexis Bougouin ,&nbsp;Fabio Dioguardi ,&nbsp;Giovanna Capparelli ,&nbsp;Eugenio Nicotra ,&nbsp;Roberto Sulpizio","doi":"10.1016/j.ijmultiphaseflow.2026.105648","DOIUrl":"10.1016/j.ijmultiphaseflow.2026.105648","url":null,"abstract":"<div><div>Geophysical granular flows, such as landslides, rock avalanches and pyroclastic flows, remain difficult to model due to their unexpectedly high mobility. Several mechanisms have been proposed to interpret this low dissipative behavior, including the flow-substrate interaction. This study addresses this issue through dedicated, well-controlled experiments on steady granular avalanches of idealized and natural flowing materials (i.e., glass beads, sand, volcanic material) along a wide variety of inclined surfaces. Our observations reveal that the basal surface condition significantly influences the propagation and deposition dynamics of granular avalanches. In particular, we identify two main types of effective basal condition - <em>smooth</em> and <em>rough</em> - based on a single dimensionless parameter: the roughness-to-grain size ratio <span><math><mrow><mi>λ</mi><mo>/</mo><mi>d</mi></mrow></math></span> with a critical transition at <span><math><mrow><mi>λ</mi><mo>/</mo><mi>d</mi><mo>≈</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span>. The dynamic modeling of granular avalanches on smooth and rough inclines is then established based on initial flow conditions, material properties, and surface characteristics. We propose a unified flow rule governed by distinct functional relationships of the inflow Froude number, depending on the repose angle and grain size of flowing material, and the basal friction angle. These results highlight the importance of accurately constraining material and basal properties in order to improve field prediction of geophysical granular avalanches.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"198 ","pages":"Article 105648"},"PeriodicalIF":3.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146186579","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 integrated machine learning approach for identifying flow patterns in porous media using principal component analysis and K-means clustering","authors":"Liangxing Li ,&nbsp;Jiabin Gui ,&nbsp;Yiwen Guo ,&nbsp;Aimad Bouloudenine ,&nbsp;Xiangyu Li ,&nbsp;Jiaojiao Lou","doi":"10.1016/j.ijmultiphaseflow.2026.105646","DOIUrl":"10.1016/j.ijmultiphaseflow.2026.105646","url":null,"abstract":"<div><div>Gas-liquid two-phase flow in porous media exists extensively in natural phenomena and numerous industrial processes, and the flow patterns of two-phase flow are crucial for understanding the flow characteristics and modeling the governing mechanisms. However, limited by the porous structure and the transient nature of two-phase flow, the traditional approaches for identifying the flow patterns in porous media often confront great challenge especially in terms of convenience and accuracy. By integrating machine learning techniques, this study proposes an integrated machine learning approach to identify air–water two-phase flow patterns in porous media coupled with the technologies of principal component analysis (PCA) and K-means clustering. Firstly, the time-domain analysis and frequency-domain analysis are carried out for the measured differential pressure signals of two-phase flow in porous media, aiming to extract typical features of two-phase flow in the time-frequency domain. Then, the Principal Component Analysis (PCA) model is developed by taking the typical features of time-frequency domain and the key physical parameters such as gas and liquid Reynolds numbers into account. The first three principal components are selected for dimensionality reduction in the PCA process. Subsequently, classification using K-means clustering enables the identification of both typical flow patterns and key transitional regimes, particularly the bubbly-slug transition. The machine learning approach provides a robust and efficient tool for the rapid identification of gas–liquid two-phase flow patterns in porous media.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"198 ","pages":"Article 105646"},"PeriodicalIF":3.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146186568","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":"On the nature of single-phase liquid heat transfer mechanisms in nucleate boiling: Evidence from high-resolution diagnostics","authors":"Gustavo M․ Aguiar,&nbsp;Matthew T. Hughes,&nbsp;Matteo Bucci","doi":"10.1016/j.ijmultiphaseflow.2026.105622","DOIUrl":"10.1016/j.ijmultiphaseflow.2026.105622","url":null,"abstract":"<div><div>We perform high-fidelity subcooled flow-boiling experiments to investigate single-phase liquid heat transfer mechanisms during nucleate boiling. Using high-speed infrared thermometry and synchronized phase-detection imaging, we obtain time-resolved and spatially resolved measurements of wall temperature, heat flux and phase in contact with the surface, and bubble-dynamics parameters across the boiling curve for three different surface types, two mass fluxes (500 and 1000 kg/m²·s), and two subcooling levels (10 and 20 K). These diagnostics allow us to isolate the liquid-side heat transfer contribution with exceptional accuracy and directly observe the physical processes governing the transfer of energy from the heating surface to the liquid phase. Our measurements show that single-phase heat transfer is the dominant heat-removal mechanism and that the corresponding heat transfer coefficient (HTC) is significantly enhanced beyond pure forced-convection values. Crucially, this enhanced HTC is strongly time-dependent and cannot be predicted by conventional quenching models. Instead, we capture its evolution using a turbulent-diffusion model in which the influence of bubbles is represented through an effective shear velocity. We also observed that the bubble wait time is not an appropriate scale for the quenching process. Instead, we identified and demonstrated the soundness of a new time scale, i.e., the liquid refreshing frequency, which quantifies the rate at which bubbles sweep and renew the liquid contacting the wall. Building on these insights, we propose a preliminary mechanistic model to predict single-phase heat transfer in subcooled nucleate boiling that incorporates both the enhanced HTC and the refreshing-frequency time scale. The model substantially outperforms legacy HFP formulations across our database, providing a basis for more predictive capabilities.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"198 ","pages":"Article 105622"},"PeriodicalIF":3.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146186565","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}