International Journal of Multiphase Flow最新文献

{"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}

{"title":"A probability model for churn flow in vertical pipes: Predicting the distribution of disturbance wave scale and void fraction","authors":"Haixiao Liu,&nbsp;Rui Guo,&nbsp;Deping Sun","doi":"10.1016/j.ijmultiphaseflow.2025.105150","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105150","url":null,"abstract":"<div><div>As a complex flow state in vertical transportation pipelines, churn flow is crucial for optimizing industrial pipeline design and improving fluid transportation efficiency. This study develops a probabilistic analysis model to explore the dynamic characteristics of churn flow in vertical pipelines and its impacts on gas-liquid two-phase flow. Interfacial waves, a key feature in two-phase flow, are essential for flow state conversion and influencing heat and mass transfer processes. The model, based on dynamic equilibrium, examines the generation and dissipation of interfacial fluctuations, treating the influence of vortices on the liquid film as a Markov process. This approach allows for the statistical stabilization of churn flow under specific conditions, facilitating predictions of liquid film thickness and void fraction. These predictions consider variables such as fluid flow rate, pipe size, and fluid physical properties, with accuracy and applicability validated through experimental data. The present study also investigates the effects of gas and liquid velocities, liquid density, liquid viscosity, liquid surface tension, and pipe diameter on the liquid film thickness and the void fraction. The sensitivity analysis reveals that the pipe diameter significantly influences the liquid film thickness, the flow field is more sensitive to the gas velocity than the liquid velocity, and the liquid density notably affects both the liquid film thickness and the void fraction.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"186 ","pages":"Article 105150"},"PeriodicalIF":3.6,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143271135","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 numerical investigation concerning wall-nucleation effects of the inception of sheet cavitation","authors":"Xinzhen Qin ,&nbsp;Yihong Chen ,&nbsp;Xianren Feng ,&nbsp;Xueming Shao ,&nbsp;Jian Deng","doi":"10.1016/j.ijmultiphaseflow.2025.105142","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105142","url":null,"abstract":"<div><div>In this study, a multiscale Euler–Lagrange method is proposed, integrating a new wall nucleation model tailored for predicting sheet cavitation dynamics. Differentiating from the previous homogeneous wall nucleation model, our approach calculates nucleation diameter based on local flow conditions. Specifically, within the flow attachment region, the nucleation diameter is dependent on the flow shear rate, whereas in separation zones, it correlates with the thickness of the low-momentum region. Transition corrections are incorporated into the delayed detached eddy simulation (DDES) model to enhance accuracy in predicting flow separation. Rigorous validation is conducted, focusing on Lagrangian bubble dynamics and predicting laminar separation. The method is then applied to investigate cavitation flow induced by an axisymmetric headform body. Predicted cavitation scenarios are compared with experimental observations, Euler cavitation simulations, and multiscale simulations employing the wall nucleation model introduced by Hsiao et al., (2017). Results demonstrate that our model accurately predicts cavity morphology and inception index, closely matching experimental findings. Moreover, our model offers a coherent explanation for the detachment position and inception index of sheet cavitation, emphasizing the pivotal role of wall nucleation in precise prediction of sheet cavitation phenomena.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"185 ","pages":"Article 105142"},"PeriodicalIF":3.6,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144869","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":"Identification of high void fraction flows using conductivity measurements and machine learning techniques","authors":"Charie A. Tsoukalas,&nbsp;Yang Zhao,&nbsp;Mamoru Ishii","doi":"10.1016/j.ijmultiphaseflow.2025.105145","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105145","url":null,"abstract":"<div><div>This study explores the application of a droplet-capable conductivity probe (DCCP-4) combined with a Kohonen self-organizing map (SOM) for identifying flow regimes in high void fraction flows. The DCCP-4, designed to accurately measure the electrical conductivity of multiphase flows, is adept at capturing the intricate details of droplet behavior within these systems. The research demonstrates the effectiveness of the combined DCCP-4 and SOM method to identify different types of annular flows. The integration of the DCCP-4 probe's precise measurements with the SOM's robust clustering capabilities results in an advanced methodology for flow regime identification. The unsupervised neural network is used to categorize high void fraction flow data into three</div><div>flow regimes. High-speed camera footage is also employed to visually corroborate the findings. Statistical distributions related to droplet, bubble, and ligament measurements are also presented to further highlight the differences between the flow regimes. This approach not only enhances the accuracy of flow characterization in multiphase systems but also provides valuable insights into the underlying physical phenomena driving these flows. The findings have significant implications for optimizing industrial processes where high void fraction flows are prevalent to safety, such as in chemical reactors, oil and gas pipelines, and nuclear reactors, by improving monitoring and control strategies.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"185 ","pages":"Article 105145"},"PeriodicalIF":3.6,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144873","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 influence of the periodic boundary conditions on the drag of random particle arrangements in PR-DNS","authors":"Hani Elmestikawy,&nbsp;Victor Chéron,&nbsp;Berend van Wachem","doi":"10.1016/j.ijmultiphaseflow.2025.105143","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105143","url":null,"abstract":"<div><div>Particle-resolved direct numerical simulation is an accurate tool for studying aspects of particle-laden flows, allowing, for instance, for the accurate estimation of fluid hydrodynamic forces on particles. While periodic boundary conditions are often used to mimic large suspensions of particles, they can introduce spurious effects if the domain size is not sufficiently large. This work investigates the effect of the domain size on the drag forces experienced by particles in random arrangements. Current practice relies on the diminishing spatial autocorrelation of the fluid velocity fluctuations as a measure to prevent periodicity effects. In this study, the impact on the drag force itself is directly monitored. First, the case of particle pair in Stokes flow is considered at varying inter-particle distances and orientations with respect to the mean flow. This provides the “worst-case scenario” for domain size, <em>i.e.</em> very dilute suspensions and low Reynolds numbers. Second, random arrangements of particles are considered with incrementally expanding periodic domain sizes. The spatial autocorrelation of the fluid velocity fluctuations shows inconsistencies for small domain sizes across different realizations. Additionally, the influence of Reynolds number and particle volume fraction on the correct domain size are investigated separately. The effect of the Reynolds number is found to be small and does not significantly contribute to the effect of domain size. On the other hand, particle volume fraction shows an impactful contribution where lower volume fractions require larger domain sizes to minimize the periodicity effects. Finally, recommendations for the required domain size for PR-DNS are presented.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"185 ","pages":"Article 105143"},"PeriodicalIF":3.6,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144876","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 investigation of turbulence characteristics in cavitating flows using BDIM and ILES method: Insights into vortex dynamics and turbulent kinetic energy","authors":"Meng Yang (孟杨),&nbsp;Huang Biao (黄彪),&nbsp;Liu Taotao (刘涛涛)","doi":"10.1016/j.ijmultiphaseflow.2025.105148","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105148","url":null,"abstract":"<div><div>The present study investigates turbulence characteristics in cavitating flows around Clark-y hydrofoil by applying the BDIM (boundary data immersion method) and ILES (implicit large eddy simulation) with our in-house code. The numerical results exhibit a satisfactory consistency with the experimental data. Through analysis of the growth of the re-entrant jet and large-scale shedding of the cavity, the turbulent structures in cavitating flows are discussed in detail. Subsequently, the vortex structure at different energy levels in turbulence are identified by the Proper Orthogonal Decomposition (POD) method, so as to extract the large-scale coherent structure in the turbulent flow field. Further analysis of turbulent kinetic energy (TKE) reveals that the instability of flow field and turbulence pulsation intensity increase under the effect of re-entrant jet and large-scale shedding of the cavity. Furthermore, the fluctuating turbulent kinetic energy (TKE) and root mean square value of fluctuating velocities at five different cross-sections become more significant, causing by the strong interactions between liquid and vapor.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"185 ","pages":"Article 105148"},"PeriodicalIF":3.6,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental study on the modulation effect of dissipation scale neutrally buoyant particles on approximate isotropic turbulence generated by horizontal oscillating grids","authors":"Zhenzhong Li ,&nbsp;Bowen Wang ,&nbsp;Yu Liu ,&nbsp;Zhen Wei ,&nbsp;Rong Chen ,&nbsp;Shanshan Bu ,&nbsp;Deqi Chen","doi":"10.1016/j.ijmultiphaseflow.2025.105144","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105144","url":null,"abstract":"<div><div>Investigating the turbulent modulation effects due to dissipation scale particles is essential for the development of a more refined interphase interaction model for particle-laden two-phase turbulence. This study used Particle Image Velocimetry (PIV) to measure the approximately isotropic turbulence generated by oscillating grids, and investigated the turbulence modulation of dissipation scale neutrally buoyant particles. In the range of grid motion parameters studied in this research, the turbulence integral length scale is approximately 1 <em>cm</em>, while the Taylor microscale is about an order of magnitude smaller than the integral scale. The turbulence dissipation scale ranges from 188 to 1358 μm. Experiments were conducted to investigate the effects of particles with diameters of 150 μm, 270 μm, and 500 μm on isotropic turbulence, with particle volume fractions ranging from 0 to 0.1%, which make the flow belongs to dilute particle-laden turbulence. It was found that in the approximate isotropic turbulence, particles exhibit the effects of energy dissipation, storage, and redistribution. Particles are also capable of absorbing the energy from the secondary mean flow and converting it into turbulent fluctuation energy through particle-fluid interactions. These mechanisms together constitute the modulation of turbulence by particles. The ability of particles to dissipate, store, and redistribute energy varies with particle diameter, making the influence of particle volume fraction closely related to the relative size of the particle diameter. Overall, when the particle scale is larger than the turbulence dissipation scale, the particles tend to enhance the turbulence, and vice versa. Since the presence of particles alters the turbulence dissipation scale, the relative size of the particle scale to the turbulence dissipation scale is an important but not the only parameter influencing particle-induced turbulence modulation. Observations from the local flow field around the particles indicate that when the particle diameter is less than the turbulence dissipation scale, the flow structures surrounding the particles remain dominated by turbulence. However, larger particles dominate the surrounding flow structures, leading to a more orderly arrangement of velocity contours around them.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"185 ","pages":"Article 105144"},"PeriodicalIF":3.6,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144867","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}