International Journal of Multiphase Flow最新文献

{"title":"Entrainment characteristics of a swirling liquid jet plunging in a quiescent pool of liquid","authors":"Toshan lal Sahu ,&nbsp;Ujjwal Chetan ,&nbsp;Saurabh Dhopeshwar ,&nbsp;Prabir Kumar Kar ,&nbsp;P. Das ,&nbsp;Rajaram Lakkaraju","doi":"10.1016/j.ijmultiphaseflow.2025.105353","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105353","url":null,"abstract":"<div><div>We have explored the entrainment characteristics of a swirling liquid jet plunging into a quiescent liquid pool. We carried out three-dimensional simulations for a range of swirl parameters <span><math><mrow><mn>0</mn><mo>.</mo><mn>5</mn><mo>≤</mo><mi>S</mi><mo>≤</mo><mn>1</mn><mo>.</mo><mn>6</mn></mrow></math></span> and axial Reynolds number of <span><math><mrow><mn>4000</mn><mo>≤</mo><mi>R</mi><mi>e</mi><mo>≤</mo><mn>12000</mn></mrow></math></span>. The main objective of the current investigation is to explore the impact of the swirl parameter on the entrainment characteristics of a swirling plunging jet. The results indicate that the air volume consistently increases up to a swirl parameter of <span><math><mrow><mi>S</mi><mo>=</mo><mn>1</mn><mo>.</mo><mn>2</mn></mrow></math></span>, beyond which it decreases for a fixed Reynolds number. The amount of air being entrained depends upon the trade-off between the axial inertia in competition with radial inertia and buoyancy. We have delineated the mechanism of transition through turbulent kinetic energy possessed by the swirling liquid jet for the range of swirl parameters considered. Further, the bubble penetration depth decreases with increasing swirl parameters. We also identified the breakup morphology of the initial air-cavity pinching-off into smaller air bubbles for the case of swirling plunging jets and compared it with their non-rotating counterpart.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"192 ","pages":"Article 105353"},"PeriodicalIF":3.6,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144656720","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 analysis of binary molten glass microspheres droplets co-directional collision behavior","authors":"Xiaolei Hu,&nbsp;Liangyu Tao,&nbsp;Wei Li,&nbsp;Jiayi Guo,&nbsp;Zhenzhen Liu,&nbsp;Nenggang Xie,&nbsp;Baohong Tong","doi":"10.1016/j.ijmultiphaseflow.2025.105366","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105366","url":null,"abstract":"<div><div>The co-directional collision behavior of molten glass microspheres plays a crucial role in determining their sphericity and physical properties. Previous studies have predominantly examined head-on collisions of counter-moving droplets. However, the mechanisms governing co-directional collisions remain inadequately understood. To bridge this gap, a three-dimensional numerical model was developed using the open-source solver <em>Basilisk</em>, which incorporates the volume-of-fluid (VOF) method with adaptive mesh refinement (AMR), to simulate molten glass microsphere collisions. In comparison with experimental observations, the effects of velocity ratio and radius ratio on co-directional collision dynamics were systematically investigated through detailed analyses of droplet morphology evolution, velocity fields, and pressure distributions. Five distinct collision regimes are identified: (Ⅰ) bouncing, (Ⅱ) coalescence, (Ⅲ) reflexive separation without satellite droplets, (Ⅳ) reflexive separation with a single satellite droplet, and (Ⅴ) reflexive separation with an ejected satellite droplet. The results demonstrated that increasing the velocity ratio shifts collision outcomes from bouncing or coalescence to reflexive separation. Satellite droplet formation was observed only at high velocity ratios when the radius ratio approaches unity, whereas a significant droplet size disparity promoted coalescence. Additionally, the transformation between kinetic energy (<em>KE</em>) and surface energy (<em>SE</em>) before and after collision was analyzed. The findings revealed that <em>KE</em> was initially converted into <em>SE</em> upon impact and subsequently partially transformed back into <em>KE</em> during axial stretching. A regime map was constructed to classify collision outcomes, highlighting the pivotal role of velocity and radius ratios in regime transitions. This study provides theoretical insights to support the optimization of molten glass microsphere production processes.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"192 ","pages":"Article 105366"},"PeriodicalIF":3.6,"publicationDate":"2025-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144631778","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":"Intelligent and quantitative ligament breakup event analysis in 65 kHz off-axis holographic video of swirl spray","authors":"Hang Zhang ,&nbsp;Yu Wang ,&nbsp;Yue Zhao ,&nbsp;Luxi Chen ,&nbsp;Yingchun Wu ,&nbsp;Chenghang Zheng ,&nbsp;Xuecheng Wu ,&nbsp;Xiang Gao","doi":"10.1016/j.ijmultiphaseflow.2025.105337","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105337","url":null,"abstract":"<div><div>The mechanism of ligament breakup events in sprays significantly impacts both daily life and industry, particularly with regard to swirl sprays in aero-engines. Specifically, three critical challenges must be addressed: tracking the trajectories of ligaments across frames, elucidating the relationships between parent and daughter ligaments, and capturing the spatial and temporal information of breakup events. This study introduces an intelligent pipeline for the quantitative analysis of ligament breakup events. The integration of Segment Anything Model 2 (SAM 2) enables automatic segmentation, producing ligament masks from low signal-to-noise ratio holographic videos. To effectively provide prompt information, four techniques are proposed: YOLO detection for initial bounding box prompts, box post-processing, video clip generation, and prompt giving. Based on the preliminary masks generated by SAM 2, the grayscale values of the masked pixels are utilized for refined segmentation through clustering of K-means, accurately delineating the internal structures and edges of the ligaments. A manually curated validation dataset is established, and three evaluation metrics (precision, recall and F1 score) are used to assess the segmentation performance of seven different methods, demonstrating the superior efficacy of the proposed approach. The influences of frame rate and image quality are also discussed. Subsequently, the centroids and areas of connected regions within the segmentation results are extracted. A light flow field is utilized to initiate ligament trajectory matching. To determine the relationship between parent and daughter ligaments during the breakup process, the stability of relative horizontal positions between connected regions before and after the breakup is analyzed, significantly reducing the calculation time. Finally, breakup lengths, ligament lengths, and breakup times are calculated to represent the statistical characteristics of breakup events.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"192 ","pages":"Article 105337"},"PeriodicalIF":3.6,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144604702","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":"Temperature response during rapid depressurization of CO2 in a pipe: Experiments and fluid-dynamics modelling","authors":"Alexandra Metallinou Log,&nbsp;Morten Hammer,&nbsp;Han Deng,&nbsp;Anders Austegard,&nbsp;Svend Tollak Munkejord","doi":"10.1016/j.ijmultiphaseflow.2025.105330","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105330","url":null,"abstract":"<div><div>The temperature evolution of <span><math><msub><mrow><mtext>CO</mtext></mrow><mrow><mtext>2</mtext></mrow></msub></math></span> during full-bore pipe depressurization events is relevant for risk assessment, e.g., for <span><math><msub><mrow><mtext>CO</mtext></mrow><mrow><mtext>2</mtext></mrow></msub></math></span> transport in the context of <span><math><msub><mrow><mtext>CO</mtext></mrow><mrow><mtext>2</mtext></mrow></msub></math></span> capture and storage (CCS). We analyse and model the temperature evolution for four different initial temperatures between <span><math><mrow><msub><mrow><mi>T</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>=</mo><mn>4</mn><mo>.</mo><mn>6</mn><mspace></mspace><mstyle><mo>∘</mo><mi>C</mi></mstyle></mrow></math></span> and <span><math><mrow><msub><mrow><mi>T</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>=</mo><mn>40</mn><mspace></mspace><mstyle><mo>∘</mo><mi>C</mi></mstyle></mrow></math></span> at supercritical pressures. All the experiments showed an analogous temperature evolution, reaching similar minimum temperatures along the pipe. The warmer the initial temperature, the earlier dry-out and faster temperature recovery was observed. Also, the coldest experiment showed evidence of formation of more dry ice.</div><div>We employ the homogeneous equilibrium model (HEM) with different heat-transfer correlations and a two-fluid model (TFM) with different slip models in order to understand the observed data. The results indicate that the heat transfer changes significantly with different thermodynamic states for the <span><math><msub><mrow><mtext>CO</mtext></mrow><mrow><mtext>2</mtext></mrow></msub></math></span>. Also, the HEM and the TFM with a RELAP-type friction model performed reasonably well at the outlet and at the closed end of the pipe, but none of the tested models were able to fully describe the strong spatial and temporal gradients observed along the pipe during the depressurization.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"192 ","pages":"Article 105330"},"PeriodicalIF":3.6,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144631313","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 of oversaturation-driven bubble growth on solid surfaces with dynamic wetting","authors":"Yifan Han ,&nbsp;Mengyuan Huang ,&nbsp;Kerstin Eckert ,&nbsp;Gerd Mutschke","doi":"10.1016/j.ijmultiphaseflow.2025.105343","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105343","url":null,"abstract":"<div><div>Dynamic wetting is known to influence the dynamics of droplets and bubbles on surfaces. In this study, we present a numerical approach to simulate the oversaturation-driven growth of single bubbles on surfaces under the influence of dynamic wetting. An existing mass transfer model implemented in the Volume of Fluid (VOF) framework Basilisk is combined with a dynamic wetting model that includes contact angle hysteresis. Motivated by the initial dominance of surface tension during bubble growth, we explore the extent to which enlarged diffusion coefficients can be used to speed up the simulations. Hereby, for calculating the instantaneous contact angle, a properly rescaled value of the contact line velocity needs to be used. An extensive validation of the simulation method is conducted, including comparisons with experimental results. The impact of dynamic wetting on bubble growth is elucidated by comparisons with the bubble behavior at static wetting.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"192 ","pages":"Article 105343"},"PeriodicalIF":3.6,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144613384","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 liquid foam flow through a diverging nozzle","authors":"Artem Skrypnik ,&nbsp;Tobias Lappan ,&nbsp;Leon Knüpfer ,&nbsp;Muhammad Ziauddin ,&nbsp;Icíar Arnal Tribaldos ,&nbsp;Natalia Shevchenko ,&nbsp;Sascha Heitkam","doi":"10.1016/j.ijmultiphaseflow.2025.105309","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105309","url":null,"abstract":"<div><div>The theory of pneumatic foam describes the transport of liquid by foam rising continuously in a vertical column. At constant cross-sectional area, the liquid foam is assumed to move similar to a plug flow with a uniform distribution of the liquid phase. To assess the pneumatic foam theory in the case of foam flowing through an expansion, we mapped the liquid fraction and measured the local velocity of a steady-state foam flow in a vertically aligned diverging nozzle by means of optical and X-ray imaging techniques. This paper presents and discusses the experimental findings in comparison with the theoretical predictions assuming different models of foam permeability. X-ray radiography revealed that the liquid fraction is decreasing with increasing cross-sectional area in nominal flow direction, which is consistent with the pneumatic foam theory, although the measured liquid fraction was at an overall higher level than predicted. In radial direction, the liquid fraction was found to increase slightly towards the nozzle wall. Similarly, non-uniform velocity profiles that deviate from the expected plug flow were revealed by X-ray particle tracking velocimetry inside the nozzle, combined with foam-adapted particle image velocimetry at the transparent nozzle wall. In conclusion, the advective transport of liquid measured in the nozzle is lower than predicted by the pneumatic foam theory.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"192 ","pages":"Article 105309"},"PeriodicalIF":3.6,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144631312","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 dynamics of single bubble rising near a vertical wall","authors":"Zhen Jiang ,&nbsp;Jiaojiao Guo ,&nbsp;Zhen Jian","doi":"10.1016/j.ijmultiphaseflow.2025.105335","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105335","url":null,"abstract":"<div><div>Bubble dynamics are fundamental in various scientific and engineering fields, from chemical engineering to environmental science. Here, single bubble rising near a vertical wall in a viscous liquid in a Hele-Shaw cell was investigated through direct numerical simulations in a two-dimensional framework, and the effects of the bubble size and of the initial distance between the wall and the bubble on the rising dynamics were studied. Different rising mechanisms such as rectilinear rising and zigzagging were identified. It is revealed that small bubble (<span><math><mrow><mi>D</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>5</mn><mo>,</mo><mn>1</mn></mrow></math></span> mm) prefers rectilinear rising, while larger bubble (<span><math><mrow><mi>D</mi><mo>=</mo><mn>2</mn><mo>,</mo><mn>3</mn><mo>,</mo><mn>4</mn><mo>,</mo><mn>5</mn></mrow></math></span> mm) prefers zigzagging. The bubble will migrate away from the vertical wall, either turn back to vertical rising or trigger an earlier zigzagging as it migrates further away. Characteristics of the bubble, such as horizontal and vertical velocities, drag coefficient and aspect ratio were analyzed and the vortex dynamics were studied. The lost of symmetry of the vortices in the wake of the bubble could be responsible for the starting of zigzagging.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"192 ","pages":"Article 105335"},"PeriodicalIF":3.6,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144670272","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":"Viscous droplets impact on rough surfaces","authors":"Lihui Liu ,&nbsp;Guobiao Cai ,&nbsp;Bohan Jiang ,&nbsp;Bijiao He ,&nbsp;Peichun Amy Tsai","doi":"10.1016/j.ijmultiphaseflow.2025.105345","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105345","url":null,"abstract":"&lt;div&gt;&lt;div&gt;We experimentally investigate the dynamics of viscous droplets impacting on rough surfaces under a broad range of Weber number (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;mi&gt;We&lt;/mi&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mn&gt;194&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;), Ohnesorge number (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;002&lt;/mn&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;mi&gt;Oh&lt;/mi&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;630&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;), and average surface roughness (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;9&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;7&lt;/mn&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mi&gt;μ&lt;/mi&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;R&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;mn&gt;19&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;5&lt;/mn&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mi&gt;μ&lt;/mi&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;). Three primary impact outcomes—jetting, spreading, and splashing—are observed. Our findings reveal that surface roughness promotes splashing by amplifying perturbations, while liquid viscosity counters this effect by dissipating the kinetic energy of the advancing lamella. We empirically describe the splashing threshold with the relation as &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;Oh&lt;/mi&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;Re&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;χ&lt;/mi&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;R&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mi&gt;K&lt;/mi&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;R&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, where the fitting parameter &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;K&lt;/mi&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;R&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; increases and &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;χ&lt;/mi&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;R&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; decreases with greater surface roughness. Moreover, the maximum spreading factor (&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;β&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;), defined as the ratio of the droplet’s maximum spreading diameter to its initial diameter, shows a pronounced dependence on surface roughness in low-viscosity conditions (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;Oh&lt;/mi&gt;&lt;mo&gt;&lt;&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;050&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;), but this dependence diminishes in high-viscosity regimes (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;Oh&lt;/mi&gt;&lt;mo&gt;≥&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;050&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;). This trend results from the interplay between viscous dissipation induced by surface roughness and the intrinsic liquid viscosity. In the low-viscosity regime, the experimental &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;β&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; is consistent with the empirical scaling law of &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;β&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mi&gt;We&lt;/mi&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mi&gt;Oh&lt;/mi&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;b&lt;/mi&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, with the fitting constants, &lt;span&gt;&lt;math&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;mi&gt;b&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;, varying with surface roughness and liquid properties. In the regime of &lt;span&gt;&lt;","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"192 ","pages":"Article 105345"},"PeriodicalIF":3.6,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144631314","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":"Hydrodynamic forces on a spherical particle in a plane Couette flow","authors":"Tongkuai Wang,&nbsp;Zhaowu Lin,&nbsp;Yu Guo,&nbsp;Zhaosheng Yu","doi":"10.1016/j.ijmultiphaseflow.2025.105341","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105341","url":null,"abstract":"<div><div>The hydrodynamic forces and torque acting on a spherical particle in a plane Couette flow are investigated numerically with the spectral element method. Both non-rotating and rotating particles in a channel with uniform or linear shear flow are considered, to evaluate the effects of rotation and linear shear, respectively. The effects of the far and near side walls on the lift force are investigated by varying the channel half width from 4 to 25 particle diameters and the near-side wall-particle separation distance from 1 to 6 particle diameters. The Reynolds number based on slip velocity and particle diameter ranges from 0.1 to 100. New correlations for drag and lift on a non-rotating particle are established for the wall-bounded Couette flow, based on simulation data. New correlations for the rotation-induced lift and torque are also proposed to account for the wall and finite Reynolds number effects.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"192 ","pages":"Article 105341"},"PeriodicalIF":3.6,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144588184","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":"Liquid evaporation from nanochannel with rough wall surface by direct simulation Monte Carlo","authors":"Ran Li,&nbsp;Ziqing Yan,&nbsp;Xiupeng Cheng,&nbsp;Yinuo Wang,&nbsp;Guodong Xia","doi":"10.1016/j.ijmultiphaseflow.2025.105352","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105352","url":null,"abstract":"<div><div>Roughness in nanoscale channels has profound influences on liquid flow and evaporation from the channel which is relevant in many cutting-edge applications. The direct simulation Monte Carlo (DSMC) method was employed to numerically study the effects of roughness shape, size and interval distance on the liquid evaporation rate from a nanochannel. It was found that the inclination angle of roughness elements plays a vital role in determining the liquid evaporation resistance of nanochannel. Under sparse roughness condition, the rectangle roughness with larger inclination angle leads to higher evaporation resistance. Under dense roughness condition, the vapor was inhibited from entering the gap between rectangle roughness and the velocity sink effect was weakened. The evaporation resistance for rectangle roughness declined as the roughness interval continued to reduce, while triangle and semicircle roughness with smaller inclination angle could retain the increase of evaporation resistance. Larger roughness size leads to higher evaporation resistance for the three roughness shapes. A phenomenological model was proposed to correlate the computed evaporation resistance; the model accounted for roughness inclination angle and had different behaviors under sparse and dense roughness conditions. The evaporation resistance was well correlated to the newly defined model with error being around ± 5 %.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"192 ","pages":"Article 105352"},"PeriodicalIF":3.6,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144557316","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}