International Journal of Multiphase Flow最新文献

{"title":"A probability model for predicting the bubble size distribution in slug flow in vertical pipes","authors":"Haixiao Liu,&nbsp;Jiawen Wang,&nbsp;Deping Sun","doi":"10.1016/j.ijmultiphaseflow.2025.105165","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105165","url":null,"abstract":"<div><div>In deep-sea mineral exploitation, slug flow shows promise for efficient mineral air-lifting but also poses risks of serious production safety accidents. Accurate prediction of the two-phase distribution in the liquid slug is crucial for efficient mineral lifting and accident prevention. This study develops a probability model for predicting the bubble size distribution of slug flow in vertical pipes. The liquid slug is divided into the near wake and far wake regions based on Taylor bubble wake influence. In the near wake, the vortex tears the liquid film at the tail of the Taylor bubble and generates new bubbles, while pushing the old bubbles to move towards the Taylor bubble, facilitating gas exchange between the Taylor bubble and the liquid slug. In the far wake region, vortices and random collisions enable dispersed bubbles to exchange gas with each other. These gas exchange processes occur continuously and maintain dynamic equilibrium in stable slug flow. Calculating the probability of the generation and death of a single bubble, along with the analysis of the bubble behavior, yields a probability model for predicting the bubble size distribution. The model is validated using experimental data and shows good consistency. The study investigated factors affecting the distribution of bubble size in slug flow, including gas phase velocity, liquid phase velocity, liquid density, liquid viscosity, and surface tension.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"187 ","pages":"Article 105165"},"PeriodicalIF":3.6,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143438275","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":"Effects of Weber number and hole location on subcritical curtain flow regimes","authors":"Alessandro Della Pia","doi":"10.1016/j.ijmultiphaseflow.2025.105163","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105163","url":null,"abstract":"&lt;div&gt;&lt;div&gt;The flow regimes of a gravitational plane liquid jet (curtain) issuing into a quiescent gaseous ambient are investigated in subcritical conditions, namely for inlet Weber number &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;W&lt;/mi&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;mo&gt;&lt;&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;. By means of three-dimensional direct numerical simulations based on the volume-of-fluid method, steady curtain base flow solutions are obtained and excited by introducing hole perturbations, whose evolution is assessed by variation of &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;W&lt;/mi&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;h&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; (i.e. the hole initial location) parameters. Depending on the combination of &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;W&lt;/mi&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;h&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;, three different flow regimes are observed. In the sheet (S) regime, the hole perturbation expands in the curtain and is convected downstream, generating secondary holes washed out at the domain outflow, leaving the curtain intact. In the transient columns (TC) regime, the secondary holes expand and merge with the primary hole, generating vertical liquid ligaments (columns) expelled from the domain in finite time, leaving the curtain again in its original state. In the columns (C) regime, the curtain finally exhibits a transition from the continuous sheet shape to a discrete permanent (i.e. stationary) columns pattern. The phase diagram of the curtain flow is drawn by representing all numerical results in the parameters space &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;W&lt;/mi&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;-&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;h&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;. It is found that the S, TC and C regimes are clustered into three distinct regions of the diagram by two theoretical curves, namely &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;X&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;c&lt;/mi&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mi&gt;W&lt;/mi&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;X&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;b&lt;/mi&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mi&gt;W&lt;/mi&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, where &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;X&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;c&lt;/mi&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;&gt;&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;X&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;b&lt;/mi&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;: for &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;h&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;&gt;&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;X&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;c&lt;/mi&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, the curtain is in the S regime; for &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;X&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;b&lt;/mi&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;&lt;&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;h&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;&lt;&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;X&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;c&lt;/mi&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, the TC regime is obtained; for &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"186 ","pages":"Article 105163"},"PeriodicalIF":3.6,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143369783","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":"Wall model for large eddy simulations accounting for particle effect","authors":"Ping Wang ,&nbsp;Zhizong Chen ,&nbsp;Nan Jin ,&nbsp;Xiaojing Zheng","doi":"10.1016/j.ijmultiphaseflow.2025.105152","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105152","url":null,"abstract":"<div><div>A new wall model is developed for the larger eddy simulation of particle-laden flow over erodible particle bed. To reasonably include particle-related physics in the model, we adopt the assumptions of conserved momentum flux and Prandtl mixing length for turbulent viscosity in the particle-laden flow. The model involves several empirical expressions, such as the non-dimensionlized particle mass flux, the mean particle saltating height and a correction coefficient that is <span><math><mrow><mo>∼</mo><mi>O</mi><mrow><mo>(</mo><mn>1</mn><mo>)</mo></mrow></mrow></math></span>. The results of wall-resolved large eddy simulation with Lagrangian particle model are taken to be the “standard data” to test the performance of the proposed wall model. Several large eddy simulations without any wall model and with wall models developed for particle-free turbulence are also employed for comparison. The comparisons show that the proposed wall model provides much better predictions of particle statistics to the “standard data” than any other methods. The results of this study highlight the significance of incorporating additional particle effects in the wall model when performing large eddy simulations of particle-laden flow on a coarse grid.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"186 ","pages":"Article 105152"},"PeriodicalIF":3.6,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143349997","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 cavity evolution of asynchronous parallel high-speed vertical water entry of cylinders","authors":"Yulin Wang 王玉琳,&nbsp;Yingjie Wei 魏英杰,&nbsp;Cong Wang 王聪","doi":"10.1016/j.ijmultiphaseflow.2025.105164","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105164","url":null,"abstract":"<div><div>This study conducted extensive experimental investigations on the asynchronous parallel high-speed vertical water entry of cylinders, examining the effects of varying lateral spacing, time intervals, and entry speeds. The research identified four distinct modes of cavity morphology for both the first and second cavities. For the first cavity, these modes include non-existent/destroyed, compressed, and quasi-single cavity, while the second cavity exhibits non-existent/destroyed, compressed, expanded, and quasi-single cavity forms. Multiple parameters were found to affect cavity morphology, with time interval emerging as a particularly crucial factor. The study revealed complex dynamics in cavity formation: the maximum diameter of the first cavity increases with increasing time intervals, while its maximum length exhibits a non-monotonic trend, initially decreasing and then increasing. The second cavity demonstrates even more intricate behavior, with its maximum diameter initially increasing, then decreasing with time intervals, followed by minor fluctuations. Its maximum length shows a pronounced non-monotonic trend, first decreasing, then increasing, followed by significant fluctuations. Notably, the position of the maximum diameter of the second cavity consistently aligns with the collapse plane of the first cavity. This study reveals complex dynamics in cavity interactions during parallel water entry based on the influence function <strong><em>φ</em></strong> defined. As the time interval increases, the impact of the second cavity on the first cavity progressively attenuates. Conversely, the influence of the first cavity on the second exhibits a non-monotonic trend: initially intensifying, then subsequently diminishing. The peak influence occurs when the time interval equals the ratio of the cylinder length to the water entry speed. Notably, when the time interval exceeds a critical threshold, defined as the ratio of the maximum length of a single cavity at the same speed to the water entry speed, the mutual influence between the first and second cavities becomes negligible. This analysis elucidates the intricate temporal dependencies in cavity formation and interaction during parallel high-speed water entries, providing valuable insights into the fluid dynamics of such phenomena.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"186 ","pages":"Article 105164"},"PeriodicalIF":3.6,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143349854","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":"Double bursting jets from a suspended water drop under one cycle of oscillation","authors":"Cheng Xu ,&nbsp;Wanyu Zhu ,&nbsp;Huihui Xia ,&nbsp;Weiwei Deng","doi":"10.1016/j.ijmultiphaseflow.2025.105151","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105151","url":null,"abstract":"<div><div>We found that a hemispherical water drop of radius of the capillary length <span><math><msub><mrow><mi>ℓ</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span> suspended on a substrate can generate a pair of bursting jets after experiencing one cycle of oscillation. The drop of initial base radius <span><math><msub><mrow><mi>R</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span> first undergoes the downward acceleration stage and reaches a peak velocity <span><math><msub><mrow><mi>V</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span> with a characteristic Weber number <span><math><mrow><mi>W</mi><mi>e</mi><mo>≡</mo><mi>ρ</mi><msubsup><mrow><mi>V</mi></mrow><mrow><mi>p</mi></mrow><mrow><mn>2</mn></mrow></msubsup><msub><mrow><mi>R</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>/</mo><mi>γ</mi></mrow></math></span>. At the end of the downward acceleration, the drop is compressed into a pancake shape with the maximum spreading diameter that scales with <span><math><msup><mrow><mi>W</mi><mi>e</mi></mrow><mrow><mn>1</mn><mo>/</mo><mn>10</mn></mrow></msup></math></span>. Subsequently, the acceleration is reversed to upward, pulling up a cylindrical cavity. The depth of the cavity increases with larger <em>We</em>. The axisymmetric cavity pinch-off is logarithmically slow and the variation of neck radius <span><math><mi>r</mi></math></span> with time <span><math><mi>τ</mi></math></span> exhibits the scaling law: <span><math><mrow><mi>r</mi><mo>∝</mo><msup><mrow><mi>τ</mi></mrow><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msup><msup><mrow><mi>e</mi></mrow><mrow><mo>−</mo><msqrt><mrow><mo>−</mo><mo>log</mo><mi>τ</mi></mrow></msqrt><mo>/</mo><mn>2</mn></mrow></msup></mrow></math></span> (<span><span>Eggers et al., 2007</span></span>). The collapse of a small cavity does not trap any bubble, forming a single Worthington-type jet. The intermediate sized cavity collapses to form two opposite bursting jets, and the inner jet is absorbed by the enclosed bubble. The collapse of the sufficiently deep cavity produces two bursting jets that are self-similar in terms of jet radius and velocity. A phase diagram of <span><math><mrow><mi>W</mi><mi>e</mi></mrow></math></span> vs <span><math><mrow><mover><mrow><mi>R</mi></mrow><mrow><mo>̃</mo></mrow></mover><mo>=</mo><msub><mrow><mi>R</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>/</mo><msub><mrow><mi>ℓ</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></math></span> is presented for categorizing the three different cavity collapse behaviors.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"186 ","pages":"Article 105151"},"PeriodicalIF":3.6,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143271136","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":"Dynamics of shear instability in A+B→C reactive flow yielding high-viscosity products","authors":"Surya Narayan Maharana ,&nbsp;Manoranjan Mishra","doi":"10.1016/j.ijmultiphaseflow.2025.105132","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105132","url":null,"abstract":"<div><div>This numerical study investigates shear instabilities in a two-layered reactive system within a 2D channel, governed by the Navier–Stokes equations. Examining laminar Poiseuille flow, we explore the shearing of reactant fluids <span><math><mi>A</mi></math></span> and <span><math><mi>B</mi></math></span>, undergoing the <span><math><mrow><mi>A</mi><mo>+</mo><mi>B</mi><mo>→</mo><mi>C</mi></mrow></math></span> reaction. The favorable shear due to increased viscosity of the product fluid <span><math><mi>C</mi></math></span> amplifies periodic perturbations, forming roll-ups resembling interfacial waves. Increased Reynolds number leads to ligament formation. Vorticity field strength correlates with product fluid viscosity, enhancing instability growth. In the stable flow regime, the streamlines initially remain horizontally straight, but they start oscillating synchronously for a favorable viscosity ratio, which amplifies the growth of roll-ups in the unstable regime. A nonlinear energy budget analysis reveals that the growth of the shear instability primarily arises from the energy contributions of axial and vertical convection, rather than from the reaction source or diffusion terms. Shear instability induces opposite transverse motion of the reaction rate and product center of mass. Measurement of transverse spreading reveals an intermediate convection-dominated time regime in unstable flow, interspersed with diffusion-dominated early and later regimes. Proximity of the reactive zone to the bottom wall induces streamlines to shift out of phase, forming humps, and changing the wavelength of perturbations with a delayed intermediate convection-dominated regime.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"186 ","pages":"Article 105132"},"PeriodicalIF":3.6,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143369782","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-induced vibration of flexible tapering hydrofoils with and without sheet cavitation","authors":"Zhi Cheng,&nbsp;Nihar B. Darbhamulla,&nbsp;Rajeev K. Jaiman","doi":"10.1016/j.ijmultiphaseflow.2025.105149","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105149","url":null,"abstract":"<div><div>In this paper, we study the fluid–structure interaction (FSI) of a flexible cantilevered tapering hydrofoil in cavitating turbulent flows. We consider a recently developed variational cavitation FSI solver employing a large-eddy simulation model, a homogeneous mixture cavitation model, and the structural mode superposition method. Of particular interest is understanding the coupled dynamics of vortex shedding and cavitation around the hydrofoil and the mechanism responsible for the self-sustained structural vibration due to the vortex-cavitation interaction. In both the cavitating and non-cavitating cases, the structural vibrations generally exhibit the amplifying trend as the structure becomes less stiff, in both the in-line and transverse directions. When sheet cavitation appears on the suction side of the hydrofoil, the magnitude of structural fluctuation is amplified nearly seven times while the average deformation remains weaker. To understand this amplification process, we systematically examine the synchronized hydroelastic coupling through pressure pulsation within the flow field, cavitation generation, and structural vibration. We find that the generation of sheet cavitation induces considerable hydrofoil vibration subjected to a flutter-like response with sustained oscillations, accompanied by the frequency lock-in behavior owing to the synchronization among the structural modes and the surface forces, as well as their harmonics. In addition, we observe that the generation of cavitation increases the structural natural frequency of the FSI system concerned.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"186 ","pages":"Article 105149"},"PeriodicalIF":3.6,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143175554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interaction between horseshoe vortex structure and sediment transport around a river rectangular pier using a solid-liquid two-phase turbulent LES model","authors":"Takashi Inoue ,&nbsp;Yoshitaka Hirotsugu ,&nbsp;Jin Kashiwada ,&nbsp;Yasuo Nihei","doi":"10.1016/j.ijmultiphaseflow.2025.105153","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105153","url":null,"abstract":"<div><div>Most river bridges are endangered by local scour upstream of bridge piers as a result of large floods. Local scouring is primarily caused by a three-dimensional horseshoe vortex (3D-HV) forming around the upstream face of the pier. Numerical simulations of local scour around a pier are mostly conducted using a fixed-bed even though the interactions between suspended sediment and HV structures (one of the factors influencing 3D-HV structures around piers) may be important. This study aims to clarify how the presence of suspended sediment affects the 3D-HV structure around a rectangular pier. We apply movable-bed analysis using a multiphase turbulent LES model (grid-averaged Lagrangian-LES model) to conduct a local scour numerical experiment around a rectangular pier. Furthermore, movable-bed and fixed-bed results are compared. The maximum scour depth in the simulation is found to be close to the value (RMS value equal to 9 %) determined experimentally. The 3D-HV structures are found to be quite different in the movable-bed and fixed-bed simulations. In particular, the HV is generally weaker in the movable-bed simulation compared to the fixed-bed simulation. The torque produced by the drag force between particles and fluid phases generated by the suspended sediment is significantly deformed, changing the 3D-HV structure.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"186 ","pages":"Article 105153"},"PeriodicalIF":3.6,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143378950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical study of enhanced boiling phenomena on vertically oriented surfaces with heterogeneous wettability: Lattice Boltzmann method","authors":"Junjie Yuan ,&nbsp;Li Liu ,&nbsp;Ruiqi Bao ,&nbsp;Haotian Luo ,&nbsp;Zheng Jia ,&nbsp;Shuo Chen ,&nbsp;Hanyang Gu","doi":"10.1016/j.ijmultiphaseflow.2025.105147","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105147","url":null,"abstract":"<div><div>Enhancing the heat transfer efficiency of exchanger tubes can reduce energy waste and lower the likelihood of tube rupture accidents. Employing mixed wettability treatment on the surface serves as a potent strategy to elevate heat transfer properties. This paper investigates the dynamic behavior of boiling bubbles adhering to a vertical surface, alongside assessing the associated heat transfer performance, utilizing the lattice Boltzmann method (LBM). The influences of hydrophobic region characteristics (spacing, width) and surface wettability, on bubble dynamics, and surface heat flux are investigated. The results show that at low superheat, the bubbles first nucleate and grow in the hydrophobic region, then slip into the hydrophilic region and leave the surface. At high superheat, the bubbles merge and form a vapor film. Driven by buoyancy, gravity, and surface tension, the vapor film moves in a wave-like manner across the surface, and a rewetting area appears at the hydrophilic-hydrophobic boundary. The heat flux at the surface increases with the increase of hydrophobic region width and spacing. It is important to note that the increase in hydrophobic region width promotes heat transfer only at low superheat, while the promotion effect of increasing the spacing is seen at high superheat. Additionally, a surface exhibiting moderate hydrophilicity demonstrates optimal heat transfer efficiency at high superheat conditions. Under the research conditions of this paper, the heat transfer enhancement rate of the mixed wetting surface is as high as 120.2 % compared to that of a purely hydrophilic surface.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"185 ","pages":"Article 105147"},"PeriodicalIF":3.6,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144871","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":"Breath of pollutants: How breathing patterns influence microplastic accumulation in the human lung","authors":"Hafiz Hamza Riaz ,&nbsp;Abdul Haseeb Lodhi ,&nbsp;Adnan Munir ,&nbsp;Ming Zhao ,&nbsp;Muhammad Hamza Ali ,&nbsp;Emilie Sauret ,&nbsp;YuanTong Gu ,&nbsp;Mohammad S. Islam","doi":"10.1016/j.ijmultiphaseflow.2025.105156","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105156","url":null,"abstract":"<div><div>Humans are likely exposed to indoor and outdoor microplastics due to increased plastic degradation processes in the last decade. When inhaled, these microplastics could lead to inflammatory and respiratory disorders. Recent studies have advanced our understanding of microplastic transport in the respiratory system; however, they often overlook the various breathing patterns, effects of particle shape and specific accumulation patterns in the tracheobronchial airways. This study uniquely investigates how microplastics of various shapes accumulate under different breathing flow rates and frequencies, providing new insights into their behavior within these critical airways. The key findings show that microplastic deposition is minimal at a low flow rate of 7.5 LPM and a cycle frequency of 0.5 Hz but increases significantly when the frequency drops to 0.25 Hz, especially in the main bronchus. Higher inhalation flow rates, such as 40 LPM, lead to greater microplastic deposition in the early generations of the tracheobronchial airways, including generations 1–8, with notable differences between the inhalation and exhalation phases. Smaller flow rates result in higher microplastic deposition in distal airways beyond generation 8. The risk of microplastic inhalation is higher in the right bronchi, with larger particles (4–10 <span><math><mrow><mi>μ</mi><mi>m</mi></mrow></math></span>) depositing more in the main bronchi at lower flow rates and smaller particles (1–3 <span><math><mrow><mi>μ</mi><mi>m</mi></mrow></math></span>) in the initial airways at higher flow rates. The findings of this study, including case-specific microplastic deposition hotspots, will contribute to the up-to-date knowledge on pollutant exposure and relevant preventive measures.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"185 ","pages":"Article 105156"},"PeriodicalIF":3.6,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}