Pub Date : 2025-11-13DOI: 10.1016/j.ijmultiphaseflow.2025.105541
Jinho Oh , Hyunduk Seo , Kyung Chun Kim
This study investigated a time-resolved three-dimensional morphology reconstruction of a deforming single bubble and visualization of velocity field, vortical structures and pressure field around the bubble.
本文研究了单气泡变形的时间分辨三维形态重建，以及气泡周围的速度场、旋涡结构和压力场的可视化。
{"title":"Three-dimensional time-resolved morphology of a deformable bubble and associated vortex structures","authors":"Jinho Oh , Hyunduk Seo , Kyung Chun Kim","doi":"10.1016/j.ijmultiphaseflow.2025.105541","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105541","url":null,"abstract":"<div><div>This study investigated a time-resolved three-dimensional morphology reconstruction of a deforming single bubble and visualization of velocity field, vortical structures and pressure field around the bubble.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"195 ","pages":"Article 105541"},"PeriodicalIF":3.8,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145569378","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}
Pub Date : 2025-11-13DOI: 10.1016/j.ijmultiphaseflow.2025.105536
Sarita Yadav, Geetanjali Chattopadhyay
The electrohydrodynamic stability of two-layer gravity-driven channel flow for low Reynolds number has been examined under the influence of an electric field applied normally to the interface between the two immiscible fluid layers. The study on the influence of a monolayer of insoluble surfactant at the fluid–fluid interface reveals that the presence of the surfactant further enhances or suppresses the electric field-induced interfacial instability. The fluids considered here for the numerical stability analyses are treated as leaky dielectrics, which are allowed to have different viscosities, densities, permittivities, and conductivities. A linear stability analysis is carried out numerically using the Chebyshev spectral collocation method to resolve disturbances across all wavenumbers, yielding a range of dispersion relations and neutral stability curves arising from the corresponding Orr–Sommerfeld eigenvalue problem. The present study focuses on the competition between the stabilizing influence of an insoluble surfactant and the destabilizing influence of an electric field. The inclination angle plays a crucial role by altering the balance between gravitational and electrohydrodynamic stresses, thereby introducing additional instability mechanisms absent in the horizontal configuration. The combined effects of an electric field and a surfactant have been studied in the context of the horizontal channel by Yadav & Chattopadhyay (2024). Our results suggest that an increase in the electric Weber number, electrical conductivity ratio and inclination angle destabilize the flow, while the other parameters considered here are seen to promote the flow stability. However, the density ratio exhibits a non-monotonic impact on the growth rate. The method of energy budget is employed to figure out the proper physical mechanisms responsible for the growth of the instability under the influence of various flow parameters. The energy budget analysis predicts that the primary energy source terms for the growth of instabilities are the work done by velocity and stress disturbances in the direction tangential to the interface and the Marangoni stress term.
{"title":"Effect of insoluble surfactant on electrohydrodynamic stability of a two-layer fluid flow in an inclined channel","authors":"Sarita Yadav, Geetanjali Chattopadhyay","doi":"10.1016/j.ijmultiphaseflow.2025.105536","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105536","url":null,"abstract":"<div><div>The electrohydrodynamic stability of two-layer gravity-driven channel flow for low Reynolds number has been examined under the influence of an electric field applied normally to the interface between the two immiscible fluid layers. The study on the influence of a monolayer of insoluble surfactant at the fluid–fluid interface reveals that the presence of the surfactant further enhances or suppresses the electric field-induced interfacial instability. The fluids considered here for the numerical stability analyses are treated as leaky dielectrics, which are allowed to have different viscosities, densities, permittivities, and conductivities. A linear stability analysis is carried out numerically using the Chebyshev spectral collocation method to resolve disturbances across all wavenumbers, yielding a range of dispersion relations and neutral stability curves arising from the corresponding Orr–Sommerfeld eigenvalue problem. The present study focuses on the competition between the stabilizing influence of an insoluble surfactant and the destabilizing influence of an electric field. The inclination angle plays a crucial role by altering the balance between gravitational and electrohydrodynamic stresses, thereby introducing additional instability mechanisms absent in the horizontal configuration. The combined effects of an electric field and a surfactant have been studied in the context of the horizontal channel by Yadav & Chattopadhyay (2024). Our results suggest that an increase in the electric Weber number, electrical conductivity ratio and inclination angle destabilize the flow, while the other parameters considered here are seen to promote the flow stability. However, the density ratio exhibits a non-monotonic impact on the growth rate. The method of energy budget is employed to figure out the proper physical mechanisms responsible for the growth of the instability under the influence of various flow parameters. The energy budget analysis predicts that the primary energy source terms for the growth of instabilities are the work done by velocity and stress disturbances in the direction tangential to the interface and the Marangoni stress term.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"195 ","pages":"Article 105536"},"PeriodicalIF":3.8,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145569381","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}
Pub Date : 2025-11-13DOI: 10.1016/j.ijmultiphaseflow.2025.105546
Xinzhe Zhang , Bin Yu , Yuanyuan Jiang , Guoju Li , Guojie Zhang
In natural gas extraction processes, effective dehydration constitutes a critical step for utilization efficiency due to substantial water vapor content. Current research emphasizes the use of expansion refrigeration technology as a clean and efficient approach for capturing water vapor. This study develops a mathematical model predicting non-equilibrium spontaneous condensation in de Laval nozzles using water vapor as the working medium, with experimental data validation. The impacts of inlet superheat, wall temperature and wall roughness on supersonic flow characteristics and non-equilibrium condensation phenomena are systematically investigated. The results demonstrate that increasing inlet superheat enhances condensation shock wave intensity while suppressing humidity range and intensity, concurrently reducing the average liquid droplet radius within the nozzle. Specifically, the average droplet radius at the nozzle outlet measures 0.148 μm (A1, subcooled steam), 0.079 μm (A4, saturated steam), and 0.029 μm (A7, superheated steam). Elevated wall temperature induces a 1930 Pa pressure increase at the nozzle axis pressure jump point (340 K compared to 300 K), with the outlet droplet radius decreasing from 0.029 μm at 340 K to 0.031 μm at 260 K. Increased wall roughness (50–200 μm range) similarly inhibits condensation, manifesting as a 14.5% decrease in humidity range at the nozzle outlet (50 μm compared to 0 μm). Overall, lower inlet superheat, wall temperature, and wall roughness are more conducive to the generation of condensation in de Laval nozzles, providing an important theoretical basis for improving the efficiency of natural gas dehydration processes.
{"title":"Effect of boundary conditions on non-equilibrium condensation of de Laval nozzles for improving natural gas dehydration","authors":"Xinzhe Zhang , Bin Yu , Yuanyuan Jiang , Guoju Li , Guojie Zhang","doi":"10.1016/j.ijmultiphaseflow.2025.105546","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105546","url":null,"abstract":"<div><div>In natural gas extraction processes, effective dehydration constitutes a critical step for utilization efficiency due to substantial water vapor content. Current research emphasizes the use of expansion refrigeration technology as a clean and efficient approach for capturing water vapor. This study develops a mathematical model predicting non-equilibrium spontaneous condensation in de Laval nozzles using water vapor as the working medium, with experimental data validation. The impacts of inlet superheat, wall temperature and wall roughness on supersonic flow characteristics and non-equilibrium condensation phenomena are systematically investigated. The results demonstrate that increasing inlet superheat enhances condensation shock wave intensity while suppressing humidity range and intensity, concurrently reducing the average liquid droplet radius within the nozzle. Specifically, the average droplet radius at the nozzle outlet measures 0.148 μm (A1, subcooled steam), 0.079 μm (A4, saturated steam), and 0.029 μm (A7, superheated steam). Elevated wall temperature induces a 1930 Pa pressure increase at the nozzle axis pressure jump point (340 K compared to 300 K), with the outlet droplet radius decreasing from 0.029 μm at 340 K to 0.031 μm at 260 K. Increased wall roughness (50–200 μm range) similarly inhibits condensation, manifesting as a 14.5% decrease in humidity range at the nozzle outlet (50 μm compared to 0 μm). Overall, lower inlet superheat, wall temperature, and wall roughness are more conducive to the generation of condensation in de Laval nozzles, providing an important theoretical basis for improving the efficiency of natural gas dehydration processes.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"195 ","pages":"Article 105546"},"PeriodicalIF":3.8,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145569326","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}
Pub Date : 2025-11-13DOI: 10.1016/j.ijmultiphaseflow.2025.105537
Dongbao Wang , Loïc Chagot , Junfeng Wang , Panagiota Angeli
This study experimentally investigated the droplet formation process under the effect of an electric field in a coaxial microchannel. Depending on the flow rates, the well-known squeezing, dripping and jetting patterns were observed. However, the effect of electric field significantly altered the flow rate ranges at which these regimes occurred. The droplet size was found to scale with the electric Bond number and the phase flow rate ratio, while two regimes emerged for the droplet size: one governed by the hydrodynamic flow field and the other governed by the electric field.
{"title":"Charged droplet formation in a co-flow microchannel with effect of electric field","authors":"Dongbao Wang , Loïc Chagot , Junfeng Wang , Panagiota Angeli","doi":"10.1016/j.ijmultiphaseflow.2025.105537","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105537","url":null,"abstract":"<div><div>This study experimentally investigated the droplet formation process under the effect of an electric field in a coaxial microchannel. Depending on the flow rates, the well-known squeezing, dripping and jetting patterns were observed. However, the effect of electric field significantly altered the flow rate ranges at which these regimes occurred. The droplet size was found to scale with the electric Bond number and the phase flow rate ratio, while two regimes emerged for the droplet size: one governed by the hydrodynamic flow field and the other governed by the electric field.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"195 ","pages":"Article 105537"},"PeriodicalIF":3.8,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145569376","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}
Pub Date : 2025-11-12DOI: 10.1016/j.ijmultiphaseflow.2025.105535
Dennis P.L. Thuy-Petrov , Niels G. Deen , Joris J.C. Remmers , Giulia Finotello
Accurate modeling of surface tension forces in Computational Fluid Dynamics (CFD) simulations of multiphase flow is crucial for applications such as droplet formation and jet breakup, especially for interfaces with high surface tension and curvature. This work integrates a Tensile Force (TF) method in a geometric Volume-of-Fluid (VOF) solver. Unlike the Continuum Surface Force (CSF) model, the TF method calculates the surface tension force directly at the interface location, thus reducing the smearing of the force around the interface. Combination with a Pressure Jump Correction (PJC) further reduces the magnitude of the forces at the interface. This lowers the intensity of problematic spurious currents and allows the simulation of multiphase flows with high surface tension and curvature, which is typically challenging for the CSF method. We validate the TF method through several simulation test cases. Results show that the TF method reduces spurious velocities by an order of magnitude compared to the CSF model. The TF accurately models capillary instability in cases where the CSF model fails. Additionally, the TF model is combined with Adaptive Mesh Refinement (AMR) and Large Eddy Simulation (LES) to simulate droplet breakup. Typical features of the bag-breakup regime are successfully reproduced. Diameters and velocities of secondary droplets are predicted with reasonable agreement to experimental data. Simulation of primary breakup of a liquid aluminium jet in the gas atomization process demonstrates the TF model in industrially relevant conditions.
{"title":"Volume-of-Fluid simulations of multiphase flows with high surface tension and curvature using a tensile force method with pressure jump correction","authors":"Dennis P.L. Thuy-Petrov , Niels G. Deen , Joris J.C. Remmers , Giulia Finotello","doi":"10.1016/j.ijmultiphaseflow.2025.105535","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105535","url":null,"abstract":"<div><div>Accurate modeling of surface tension forces in Computational Fluid Dynamics (CFD) simulations of multiphase flow is crucial for applications such as droplet formation and jet breakup, especially for interfaces with high surface tension and curvature. This work integrates a Tensile Force (TF) method in a geometric Volume-of-Fluid (VOF) solver. Unlike the Continuum Surface Force (CSF) model, the TF method calculates the surface tension force directly at the interface location, thus reducing the smearing of the force around the interface. Combination with a Pressure Jump Correction (PJC) further reduces the magnitude of the forces at the interface. This lowers the intensity of problematic spurious currents and allows the simulation of multiphase flows with high surface tension and curvature, which is typically challenging for the CSF method. We validate the TF method through several simulation test cases. Results show that the TF method reduces spurious velocities by an order of magnitude compared to the CSF model. The TF accurately models capillary instability in cases where the CSF model fails. Additionally, the TF model is combined with Adaptive Mesh Refinement (AMR) and Large Eddy Simulation (LES) to simulate droplet breakup. Typical features of the bag-breakup regime are successfully reproduced. Diameters and velocities of secondary droplets are predicted with reasonable agreement to experimental data. Simulation of primary breakup of a liquid aluminium jet in the gas atomization process demonstrates the TF model in industrially relevant conditions.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"195 ","pages":"Article 105535"},"PeriodicalIF":3.8,"publicationDate":"2025-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145568895","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}
Pub Date : 2025-11-12DOI: 10.1016/j.ijmultiphaseflow.2025.105538
Leandro Saraiva Valim , Luiz H. M. Lino , Adriana Teixeira , Adrieli Alcaires de Souza , Amadeu K. Sum , Rigoberto E. M. Morales , Moisés A. Marcelino Neto , Celina Kakitani , Laércio M. Junior , Annie Fidel-Dufour , Nicolas Lesage , Eric Serris , Jean-Michel Herri , Gianluca Lavalle , Ana Cameirão
A common challenge faced by oil and gas operators is the formation of gas hydrate blockages in production lines. There is no consensus on the methodologies and apparatus used to assess gas hydrate blockage risk, and extrapolating laboratory results to field conditions remains a significant challenge. This highlights the importance of comparing different techniques and experimental scales. This study aims to investigate the influence of key variables, such as shear, gas-liquid ratio, water cut, salinity, subcooling, gas composition, and wax content, on gas hydrate transportability at different scales. From an industrial perspective, the objective is to determine the most effective technique for translating laboratory data into field-scale applications. To this end, three experimental setups are employed: a high-pressure rheometer, a rock-flow cell, and a pilot-scale flow loop.
{"title":"Comparative assessment of gas hydrate transportability at different scales","authors":"Leandro Saraiva Valim , Luiz H. M. Lino , Adriana Teixeira , Adrieli Alcaires de Souza , Amadeu K. Sum , Rigoberto E. M. Morales , Moisés A. Marcelino Neto , Celina Kakitani , Laércio M. Junior , Annie Fidel-Dufour , Nicolas Lesage , Eric Serris , Jean-Michel Herri , Gianluca Lavalle , Ana Cameirão","doi":"10.1016/j.ijmultiphaseflow.2025.105538","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105538","url":null,"abstract":"<div><div>A common challenge faced by oil and gas operators is the formation of gas hydrate blockages in production lines. There is no consensus on the methodologies and apparatus used to assess gas hydrate blockage risk, and extrapolating laboratory results to field conditions remains a significant challenge. This highlights the importance of comparing different techniques and experimental scales. This study aims to investigate the influence of key variables, such as shear, gas-liquid ratio, water cut, salinity, subcooling, gas composition, and wax content, on gas hydrate transportability at different scales. From an industrial perspective, the objective is to determine the most effective technique for translating laboratory data into field-scale applications. To this end, three experimental setups are employed: a high-pressure rheometer, a rock-flow cell, and a pilot-scale flow loop.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"195 ","pages":"Article 105538"},"PeriodicalIF":3.8,"publicationDate":"2025-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145569379","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}
Pub Date : 2025-11-11DOI: 10.1016/j.ijmultiphaseflow.2025.105527
Xiaohan Zheng , Zhijun Zhang , Guohua Tu , Chengwang Xiong , Muyang Wang , Shiping Wang
The aim of this study is to investigate the impact of Froude number, ventilation rate, and ventilation slit size on air-layer drag reduction (ALDR) in an axisymmetric underwater vehicle. Experiments were carried out in a recirculating water tunnel with a scaled-down SUBOFF submarine model, and the results were compared with numerical simulations performed using OpenFOAM. Five distinct air-layer morphologies are identified, distinguished by their symmetry and wake stability, which result in structures ranging from stable, symmetric layers to unstable, foam-like formations. The formation of these morphologies is governed by the interplay between buoyancy and inertia, with an increasing Froude number enhancing inertial forces over buoyancy to promote a transition from asymmetric to symmetric layers, while the ventilation rate primarily dictates the air layer coverage and the onset of instability. Moreover, larger slit sizes promote the formation of longer and thicker air layers, yet increased instability is observed at excessive ventilation rates. Optimal drag reduction occurs when low Froude numbers are paired with moderate ventilation rates, thereby facilitating the formation of a continuous and stable air layer. With further increases in ventilation rates, although wall shear stress is reduced over most of the surface, boundary layer separation is significantly enhanced, with a low-pressure region forming at the tail that considerably increases pressure drag. Consequently, the net drag reduction is weaker than expected at very high ventilation rates.
{"title":"On the effects of ventilation rate and Froude number on air-layer drag reduction over an axisymmetric underwater vehicle","authors":"Xiaohan Zheng , Zhijun Zhang , Guohua Tu , Chengwang Xiong , Muyang Wang , Shiping Wang","doi":"10.1016/j.ijmultiphaseflow.2025.105527","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105527","url":null,"abstract":"<div><div>The aim of this study is to investigate the impact of Froude number, ventilation rate, and ventilation slit size on air-layer drag reduction (ALDR) in an axisymmetric underwater vehicle. Experiments were carried out in a recirculating water tunnel with a scaled-down SUBOFF submarine model, and the results were compared with numerical simulations performed using OpenFOAM. Five distinct air-layer morphologies are identified, distinguished by their symmetry and wake stability, which result in structures ranging from stable, symmetric layers to unstable, foam-like formations. The formation of these morphologies is governed by the interplay between buoyancy and inertia, with an increasing Froude number enhancing inertial forces over buoyancy to promote a transition from asymmetric to symmetric layers, while the ventilation rate primarily dictates the air layer coverage and the onset of instability. Moreover, larger slit sizes promote the formation of longer and thicker air layers, yet increased instability is observed at excessive ventilation rates. Optimal drag reduction occurs when low Froude numbers are paired with moderate ventilation rates, thereby facilitating the formation of a continuous and stable air layer. With further increases in ventilation rates, although wall shear stress is reduced over most of the surface, boundary layer separation is significantly enhanced, with a low-pressure region forming at the tail that considerably increases pressure drag. Consequently, the net drag reduction is weaker than expected at very high ventilation rates.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"195 ","pages":"Article 105527"},"PeriodicalIF":3.8,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145517913","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}
Pub Date : 2025-11-11DOI: 10.1016/j.ijmultiphaseflow.2025.105524
Jianhao Liu , Lianzhou Wang , Xinyu Liu
This study proposes a novel cavitation model that retains the second-order inertia term in the Rayleigh-Plesset (R-P) equation. This treatment captures the acceleration and deceleration phases of bubble growth and collapse, and establishes a fundamentally novel expression for the cavitation model. In place of traditional empirical constants, the model introduces physically interpretable parameters, including the critical nucleus radius and the molar density of non-condensable gas (NCG). Model performance was evaluated through simulations of cavitating flows around a NACA0015 hydrofoil and in a venturi tube using the open-source CFD (Computational Fluid Dynamics) platform OpenFOAM. The results were compared against those from the classical Schnerr–Sauer model and experimental data. For the hydrofoil case, the new model achieves improved agreement with experimental results in terms of lift/drag coefficients and surface pressure distribution. Notably, it reproduces more intense re-entrant jet structures and a more realistic bubble collapse process during unsteady cavitation shedding. In the venturi tube case, this model predicts the critical pressure ratio of the "cavitation-induced choked flow" phenomenon more accurately. Moreover, the dominant frequency of cavitation oscillation obtained when the pressure ratio is 0.5 is closer to the experimental value, and the reproduced bubble tail morphology is similar to the experimental observation. The proposed model accurately predicts cavitation behavior, demonstrating its significance for the advancement of numerical simulation tools for cavitation.
{"title":"Implementation and validation of a cavitation model with bubble inertia second-order term and non-condensable gas effects","authors":"Jianhao Liu , Lianzhou Wang , Xinyu Liu","doi":"10.1016/j.ijmultiphaseflow.2025.105524","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105524","url":null,"abstract":"<div><div>This study proposes a novel cavitation model that retains the second-order inertia term in the Rayleigh-Plesset (R-P) equation. This treatment captures the acceleration and deceleration phases of bubble growth and collapse, and establishes a fundamentally novel expression for the cavitation model. In place of traditional empirical constants, the model introduces physically interpretable parameters, including the critical nucleus radius and the molar density of non-condensable gas (NCG). Model performance was evaluated through simulations of cavitating flows around a NACA0015 hydrofoil and in a venturi tube using the open-source CFD (Computational Fluid Dynamics) platform OpenFOAM. The results were compared against those from the classical Schnerr–Sauer model and experimental data. For the hydrofoil case, the new model achieves improved agreement with experimental results in terms of lift/drag coefficients and surface pressure distribution. Notably, it reproduces more intense re-entrant jet structures and a more realistic bubble collapse process during unsteady cavitation shedding. In the venturi tube case, this model predicts the critical pressure ratio of the \"cavitation-induced choked flow\" phenomenon more accurately. Moreover, the dominant frequency of cavitation oscillation obtained when the pressure ratio is 0.5 is closer to the experimental value, and the reproduced bubble tail morphology is similar to the experimental observation. The proposed model accurately predicts cavitation behavior, demonstrating its significance for the advancement of numerical simulation tools for cavitation.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"195 ","pages":"Article 105524"},"PeriodicalIF":3.8,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145569373","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}
Pub Date : 2025-11-11DOI: 10.1016/j.ijmultiphaseflow.2025.105531
Chang Liu , Fu-Ren Ming , Jing-Ping Xiao , Jia-Jie Wang , A-Man Zhang
The water entry of vehicles generates complex coupled dynamics involving cavity evolution and hydrodynamic forces, but the current understanding of these mechanisms requires further clarification. This paper develops an advanced water-entry experimental system featuring a novel optical image correction method and a high-impact-resistant measurement technique. Meanwhile, the Eulerian finite element method is applied for auxiliary analyses, and its accuracy and convergence are subsequently verified. Systematic investigations reveal that the wetting of the vehicle’s surface modulates force variations during water entry, while the pulsation of the cavity drives the internal pressure cyclical fluctuations. Notably, the Fr number and attitude angle critically govern cavity evolution and hydrodynamic force characteristics of the truncated cone vehicle. The peak coefficients of impact pressure, axial/normal force, and pitch torque are independent of the Fr numbers, and the cavity internal pressure decays linearly under varying Fr numbers. Moreover, the maximum axial and normal force coefficients exhibit approximate linear relationships with and ( is the attitude angle). Furthermore, the attenuation of internal cavity pressure becomes increasingly pronounced at larger attitude angles.
{"title":"Experimental study on coupling mechanism between cavity evolution and force characteristics during water entry of a truncated cone vehicle","authors":"Chang Liu , Fu-Ren Ming , Jing-Ping Xiao , Jia-Jie Wang , A-Man Zhang","doi":"10.1016/j.ijmultiphaseflow.2025.105531","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105531","url":null,"abstract":"<div><div>The water entry of vehicles generates complex coupled dynamics involving cavity evolution and hydrodynamic forces, but the current understanding of these mechanisms requires further clarification. This paper develops an advanced water-entry experimental system featuring a novel optical image correction method and a high-impact-resistant measurement technique. Meanwhile, the Eulerian finite element method is applied for auxiliary analyses, and its accuracy and convergence are subsequently verified. Systematic investigations reveal that the wetting of the vehicle’s surface modulates force variations during water entry, while the pulsation of the cavity drives the internal pressure cyclical fluctuations. Notably, the <em>Fr</em> number and attitude angle critically govern cavity evolution and hydrodynamic force characteristics of the truncated cone vehicle. The peak coefficients of impact pressure, axial/normal force, and pitch torque are independent of the <em>Fr</em> numbers, and the cavity internal pressure decays linearly under varying <em>Fr</em> numbers. Moreover, the maximum axial and normal force coefficients exhibit approximate linear relationships with <span><math><mrow><mo>tan</mo><msub><mrow><mi>θ</mi></mrow><mrow><mn>0</mn></mrow></msub></mrow></math></span> and <span><math><mrow><mo>cot</mo><msub><mrow><mi>θ</mi></mrow><mrow><mn>0</mn></mrow></msub></mrow></math></span> (<span><math><msub><mrow><mi>θ</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span> is the attitude angle). Furthermore, the attenuation of internal cavity pressure becomes increasingly pronounced at larger attitude angles.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"195 ","pages":"Article 105531"},"PeriodicalIF":3.8,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145517914","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}
Pub Date : 2025-11-10DOI: 10.1016/j.ijmultiphaseflow.2025.105534
Arindam Basak , Jai Prakash , G.P. Raja Sekhar
Surfactant impurities in multiphase emulsions can significantly modify the dynamics of small droplets by altering interfacial tension through adsorption–desorption kinetics. These interfacial variations are governed by the surface Péclet number, , which compares advective and diffusive transport of surfactants along the interface. While the effects of have been extensively studied in unbounded domains, their influence under confinement remains underexplored. In this work, we investigate the effects of small on the thermocapillary migration of a surfactant-laden spherical droplet near a planar wall, subjected to a uniform thermal gradient. Assuming negligible fluid inertia, we solve the axisymmetric Stokes equations inside and outside the droplet using a regular perturbation expansion in , formulated in bispherical coordinates via a streamfunction approach. A semi-analytical solution is developed to determine the droplet’s migration velocity and the associated flow fields. Our results reveal that surfactants begin to affect droplet motion at first order in , where thermocapillary stresses dominate the dynamics. For low viscosity ratios, the migration velocity increases rapidly with wall separation before saturating, while for higher viscosity ratios, saturation occurs at larger separations. We define a characteristic ‘screening length,’ the separation distance at which wall effects become negligible, which increases with both the viscosity ratio and the droplet-wall distance. Streamline analysis further reveals that, near the wall, flow is confined to a squeezed recirculation zone beneath the droplet, which transitions into broader recirculating structures as the droplet moves away. These findings provide new insights into the coupled effects of surfactant transport, confinement, and thermocapillarity, with potential applications in microfluidic and emulsion-based systems.
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