International Journal of Multiphase Flow最新文献

{"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}

{"title":"Flow regime identification and fluid dynamic forces in two-phase flow through staggered tube bundles","authors":"Peize Han ,&nbsp;Zhengqiao Chen ,&nbsp;Penghui Ma ,&nbsp;Wei Tan ,&nbsp;Guorui Zhu","doi":"10.1016/j.ijmultiphaseflow.2026.105645","DOIUrl":"10.1016/j.ijmultiphaseflow.2026.105645","url":null,"abstract":"<div><div>The development of efficient and compact shell-and-tube heat exchangers has brought flow-induced vibrations in tube bundles into the spotlight. Comprehending the two-phase flow regimes within tube bundles and their associated fluid-induced excitation is crucial for exploring flow-induced vibrations. However, the complexity of two-phase flow between tube bundles and the difficulty in measuring fluid forces pose significant challenges to flow regime identification and fluid excitation studies. In this study, a flow regime identification system was developed by utilizing a flow pressure testing device. The dynamic fluid forces exerted by air-water two-phase flow on horizontal tube bundles under diverse conditions were analyzed. The flow regimes between tube bundles were identified and classified by combining images with wavelet analysis of the fluid pressure around the tubes. Wavelet analysis effectively extracts local features from non-stationary fluid pressure signals, enabling the newly developed flow regime recognition system to achieve higher accuracy and enhancing the analysis of flow field pressure. Furthermore, time-domain and frequency-domain analyses characterized the fluid forces acting on the tube bundle across different flow regimes. The results revealed that the drag force is predominantly governed by large-scale flow structures, while the lift force is sensitive to local dynamic variations. Their dynamic evolution fundamentally arises from non-monotonic changes in flow regime structure, turbulence intensity, and fluid-structure interaction strength induced by varying flow conditions. Envelope spectra were then constructed to determine the fluid force spectral characteristics for each flow regime. This work advances research on flow regime identification and flow-induced vibration prediction for shell-and-tube heat exchanger design and operation.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"198 ","pages":"Article 105645"},"PeriodicalIF":3.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146186580","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":"Elongated bubble centring and high-viscosity liquids in horizontal gas-liquid slug flow: Empirical analyses and novel theory","authors":"Sean J. Perkins","doi":"10.1016/j.ijmultiphaseflow.2025.105430","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105430","url":null,"abstract":"<div><div>Elongated bubble centring—an obscure counter-buoyant phenomenon encountered in horizontal gas-liquid slug flow—is correlated with liquid viscosity and their connection is theorized. Extracting from three sets of high-viscosity liquid (HVL) photographic data with <span><math><mrow><msub><mrow><mi>μ</mi></mrow><mrow><mstyle><mi>L</mi></mstyle></mrow></msub><mo>∈</mo><mrow><mo>[</mo><mn>1</mn><mo>,</mo><mn>960</mn><mo>]</mo></mrow><mspace></mspace><mstyle><mi>m</mi><mi>P</mi><mi>a</mi></mstyle><mspace></mspace><mstyle><mi>s</mi></mstyle></mrow></math></span> and <span><math><mrow><mi>D</mi><mo>∈</mo><mrow><mo>[</mo><mn>20</mn><mo>,</mo><mn>50</mn><mo>.</mo><mn>8</mn><mo>]</mo></mrow><mspace></mspace><mstyle><mi>m</mi><mi>m</mi></mstyle></mrow></math></span>, the degree of incurred centring is found to increase, generally, in proportion to <span><math><msub><mrow><mi>μ</mi></mrow><mrow><mstyle><mi>L</mi></mstyle></mrow></msub></math></span> for a wide range of operational rates as evidenced through measurements at bubble nose, body and tail. It is demonstrated that full and nearly-symmetric centring can occur in HVL-containing flows—the former at relatively low inertial supply in contradiction to water-based dynamics. Qualitative advancements regarding the mechanistic nature of bubble centring and its plausible function within flow pattern transition theory are presented. Elaborating on recent modelling efforts, four distinct hypotheses are formulated: 1) film region laminarity as a modulator for centring; 2) boundary layer theory in slug flow to differentiate an outer-layer, relative motion-dominated film flow necessary for the initiation of centring; 3) wedge theory—a plausible alternative mechanism for partial-centring; and 4) a novel framework for the slug-annular transition composed of two unique mechanisms—centring and coalescence. The postulated boundary layer theory is investigated using a calibrated case of HVL slug flow and a dynamical environment conducive to centring mechanism proliferation is calculated.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"198 ","pages":"Article 105430"},"PeriodicalIF":3.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146186564","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":"Long-wave instability of stratified two-phase MHD channel flow","authors":"Arseniy Parfenov,&nbsp;Alexander Gelfgat,&nbsp;Neima Brauner","doi":"10.1016/j.ijmultiphaseflow.2026.105616","DOIUrl":"10.1016/j.ijmultiphaseflow.2026.105616","url":null,"abstract":"<div><div>Instability of a stratified two-phase MHD parallel flow between two infinite plates is addressed. We examine the effect of the transverse magnetic field on the base flow and long wave instability of a two-layer system consisting of conductive liquid and non-conductive gas. Both perfectly insulating and perfectly conducting boundaries are considered. To capture the behavior at small but finite wavenumbers, the conventional first-order long-wave stability analysis is extended to higher order terms. Using mercury-air system as a representative test case, the results demonstrate distinct and non-similar base flow and disturbance profiles, as well as different stability maps for insulating versus conducting boundaries. The stability diagrams reveal a non-monotonic influence of the magnetic field on flow stability, showing that, in addition to its expected stabilizing effect, the field can also induce destabilization under certain conditions. Inspection of the disturbance profiles indicates that despite the strong damping of mercury flow by the magnetic field, interaction of the two fluids at the interface and the shear-induced instabilities in the gas layer dominate and can lead to flow destabilization as the magnetic field strength increases.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"198 ","pages":"Article 105616"},"PeriodicalIF":3.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146186629","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":"Curvature analysis of the projections of the 3D liquid structures","authors":"Longxiang Huang ,&nbsp;Benjamin Duret ,&nbsp;François-Xavier Demoulin","doi":"10.1016/j.ijmultiphaseflow.2026.105607","DOIUrl":"10.1016/j.ijmultiphaseflow.2026.105607","url":null,"abstract":"<div><div>This study investigates the relationship between three-dimensional liquid structures and their two-dimensional projections using curvature analysis. Liquid structures are generated via a direct numerical simulation (DNS) solver for two-phase flow, and their two-dimensional projections are obtained by accumulating the Volume-of-Fluid field onto a single plane, simulating an imaging process. Curvature analysis is applied to both the three-dimensional data and the projected images across a range of Weber numbers and liquid volume fractions. Representative test cases illustrate the influence of structural superposition within this framework. Results indicate that, despite inherent projection-related biases, the curvature distributions derived from two-dimensional projections effectively capture the morphological characteristics of the original three-dimensional shapes. Key geometric features remain largely consistent across varied flow conditions. This work demonstrates the reliability of curvature-based image post-processing and outlines future pathways for integrating experimental imaging with numerical simulations under a unified curvature-analysis framework.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"197 ","pages":"Article 105607"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974414","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":"Adaptively reconstructed spectral eddy-viscosity in large eddy simulations of particle-laden isotropic turbulence, Part II: Number density spectra and inertial range clustering","authors":"Michał Rajek ,&nbsp;Jacek Pozorski","doi":"10.1016/j.ijmultiphaseflow.2026.105626","DOIUrl":"10.1016/j.ijmultiphaseflow.2026.105626","url":null,"abstract":"<div><div>Large eddy simulations (LES) of isotropic turbulence coupled with the Lagrangian particle tracking have been consistently disregarded as a means of exploring the physics underlying turbulent dispersed two-phase flows with a fully developed inertial subrange. In the present work, we determine the impact of our recently developed adaptively reconstructed spectral eddy-viscosity on the dynamics of small, heavy inertial particles at high Reynolds numbers. We use the particle number density spectrum to assess the ability of LES to predict particle clustering at distances exceeding the Kolmogorov length scale. We demonstrate that the functional form of the spectral eddy-viscosity has in general a moderate impact on the quantitative prediction of this phenomenon, while preserving qualitative agreement between LES and reference direct numerical simulations (DNS). By comparing the results against a state-of-the-art point-particle DNS, we demonstrate that the adaptively reconstructed closure enhances the predictive capabilities of LES for a wide range of Stokes and Reynolds numbers, providing the opportunity to explore the inertial-range clustering of dispersed particles over a broad spectrum of length scales. We point out that, assuming sufficient spatial resolution, the LES enriched with the proposed spectral eddy-viscosity becomes a reliable method for exploring the influence of large, energy-containing flow scales on the dynamics of inertial particles suspended in isotropic turbulence, particularly at Reynolds numbers that are currently unachievable in DNS. We further argue that this approach can support ongoing efforts to develop theories concerning the turbulent transport of dispersed particles.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"197 ","pages":"Article 105626"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146170489","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}