Physics of Fluids最新文献_第6页

Critical parameters of the Jamin effect on the oil droplet passing through an abruptly constricted capillary tube laden with sodium dodecyl sulfate solutions 贾明效应对油滴通过装有十二烷基硫酸钠溶液的突然收缩毛细管的关键参数

2区工程技术

Physics of Fluids Pub Date : 2025-01-01 DOI: 10.1063/5.0252302

Xiaoye Yang, Lu Jiang, Gongqi Cao, Qing He, Menghan Zhang, Jianlin Liu

{"title":"Critical parameters of the Jamin effect on the oil droplet passing through an abruptly constricted capillary tube laden with sodium dodecyl sulfate solutions","authors":"Xiaoye Yang, Lu Jiang, Gongqi Cao, Qing He, Menghan Zhang, Jianlin Liu","doi":"10.1063/5.0252302","DOIUrl":"https://doi.org/10.1063/5.0252302","url":null,"abstract":"The Jamin effect, as a resistance arising from the morphological changes of droplets during two-phases flow in the capillary tube, plays a crucial role in enhancing the oil recovery efficiency (EOR) in petroleum engineering. In the present study, we investigate the critical parameters of the Jamin effect in a sloped capillary tube laden with water and sodium dodecyl sulfate (SDS) solutions, including the critical water velocity and pressure difference. The pinning behavior of the oil droplet is observed in the waterflood with a lower velocity, while depinning and rupturing behavior occur at the higher velocity. Hereto, we build a mechanics model to analyze the underlying mechanism of the Jamin effect in the sloped capillary tube with varying cross sections. Using this theoretical model, we determine the critical velocity required for the depinning of the oil droplet. The results reveal that the critical velocity decreases with the decrease in sloped angles, consistent with the experimental results. Moreover, we find that oil droplets can pass through the entire sloped capillary tube more easily in SDS solutions than in water, and the required time becomes shorter with the decrease in sloped angles and increase in SDS concentrations. To address this, a theoretical model is established to determine the minimum applied pressure difference. These findings provide a deep insight into the mechanisms of oil displacement and contribute to achieving the higher EOR.","PeriodicalId":20066,"journal":{"name":"Physics of Fluids","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147917902","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}

引用次数: 6

Optimization of drag-reduction microstructure parameters and study of the drag reduction mechanism in a rotating flow field 旋转流场减阻微结构参数优化及减阻机理研究

2区工程技术

Physics of Fluids Pub Date : 2025-01-01 DOI: 10.1063/5.0249438

Zhiyi Yuan, Maocheng Ji, Jianyong Li, Yongqi Zhang, Xinzhong Song, Zunxing Wang, Jianfeng Li, Jia Man

{"title":"Optimization of drag-reduction microstructure parameters and study of the drag reduction mechanism in a rotating flow field","authors":"Zhiyi Yuan, Maocheng Ji, Jianyong Li, Yongqi Zhang, Xinzhong Song, Zunxing Wang, Jianfeng Li, Jia Man","doi":"10.1063/5.0249438","DOIUrl":"https://doi.org/10.1063/5.0249438","url":null,"abstract":"Fluid drag greatly lowers the efficiency and increases the energy consumption of underwater vehicles and devices working in similar environments. Therefore, drag reduction has become a major topic in fluids research. Inspired by the high drag-reduction effect of shark skin, this paper experimentally and numerically investigates the drag-reduction performance of a bionic shark skin microstructure with a triangular cross section. The structural parameters are optimized through numerical simulations. The microstructure reduces the drag by reducing the velocity gradient near the wall and changes the turbulent kinetic energy distribution in the flow field near the wall. Next, samples of microstructures were prepared using the template method. Experimental rheometer tests revealed a drag reduction rate of 14.29% on the microstructure surface under the set experimental conditions. Experiments and simulations have demonstrated the high drag-reduction effect of the microstructures within a rotating flow field. The developed method and theoretical basis for numerical simulations of rotating flow fields can be utilized in pump machinery such as magnetic levitation centrifugal flow pumps.","PeriodicalId":20066,"journal":{"name":"Physics of Fluids","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147915198","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}

引用次数: 9

A study on the droplet-jet electrospinning modes: Dynamic behavior and control theory 液滴喷射静电纺丝模式的研究：动力学行为与控制理论

2区工程技术

Physics of Fluids Pub Date : 2025-01-01 DOI: 10.1063/5.0247543

Huilin Xu, Liming Wang, Xiaohong Qin

{"title":"A study on the droplet-jet electrospinning modes: Dynamic behavior and control theory","authors":"Huilin Xu, Liming Wang, Xiaohong Qin","doi":"10.1063/5.0247543","DOIUrl":"https://doi.org/10.1063/5.0247543","url":null,"abstract":"The steady droplet-jet electrospinning mode is a preferred mode for the production of fine nanofibers. However, it can only be achieved within a narrow range of operating parameters. The experimental findings on the range are not universally applicable due to the coupled interactions among solution properties, electric field configurations, and operating parameters. Additionally, the dynamic behavior of the meniscus complicates the identification of stable operating parameters. The shape parameters of the meniscus, such as volume and contact angle, offer a unified and easily measurable evaluation of the dynamic stability, yet a comprehensive investigation is lacking. In this paper, we identified various droplet-jet electrospinning modes and dynamic transitions between them from captured images of droplet-jet electrospinning process. Subsequently, the meniscus volumes and electrical contact angles in one-jet modes were measured by an image processing method. Based on the relationship between inflow and outflow rates, characterized by the fluctuations of meniscus volume, the operating parameters were classified into oversupply, equilibrium, and undersupply regimes. We employed the Gibbs inequality condition to explain the principles governing the stable range of electrical contact angles in these regimes. The alignment between experimental results and the predicted values supports the assumption that the range of electrical contact angles in steady droplet-jet electrospinning modes only depends on the intrinsic properties of the liquid solution and the needle geometry. Furthermore, we established a voltage-control law between the electrical contact angle and applied voltage, inspired by the electrowetting theory. These findings provide a theoretical foundation for controlling droplet-jet electrospinning processes.","PeriodicalId":20066,"journal":{"name":"Physics of Fluids","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147905007","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}

引用次数: 1

Influence of thermal effects on the dynamic behavior of blood droplets on a superhydrophobic surface 热效应对超疏水表面上血滴动力学行为的影响

2区工程技术

Physics of Fluids Pub Date : 2025-01-01 DOI: 10.1063/5.0248707

Longsheng Lu, Jinwei Kou, Biao Tang, Yingxi Xie, Jiao Gao, Long Wang, Kaikai Li

{"title":"Influence of thermal effects on the dynamic behavior of blood droplets on a superhydrophobic surface","authors":"Longsheng Lu, Jinwei Kou, Biao Tang, Yingxi Xie, Jiao Gao, Long Wang, Kaikai Li","doi":"10.1063/5.0248707","DOIUrl":"https://doi.org/10.1063/5.0248707","url":null,"abstract":"The high temperatures generated during the operation of high-frequency surgical electrodes can cause biological tissues (especially blood) to crust and adhere to the electrode surface, seriously affecting the quality and efficiency of the procedure. Currently, an effective anti-adhesion approach is to construct superhydrophobic microstructures on the electrode surface. However, the micro-mechanisms of antiadhesion under the influence of high temperatures are still incomplete. Herein, this study focuses on the dynamic growth and evolution of blood droplets on a superhydrophobic microstructured surface (SMS) under thermal effects above 100 °C. The research demonstrated that as the substrate temperature increases gradually, the internal fluid perturbation of the blood droplets intensifies, and the air layer trapped by the SMS is subjected to thermal expansion. Consequently, the SMS is unable to provide sufficient adhesion for the growth of the blood coagulum, leading to a significant decrease in the stability of its binding to the substrate and thus the formation of self-desorption. Particularly, it was discovered for the first time that the shell wall of the blood coagulum is layered, a phenomenon related to mass transfer in the Marangoni flow within the droplet under thermal effects. These detailed findings facilitate comprehension of the anti-adhesion mechanism of SMSs, thereby providing a theoretical foundation for the optimization of future surgical electrodes.","PeriodicalId":20066,"journal":{"name":"Physics of Fluids","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147330596","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}

引用次数: 0

Water transport mechanisms during pressure-driven transport through polyamide nanogaps. 通过聚酰胺纳米间隙的压力驱动运输过程中的水运输机制。

IF 4.3 2区工程技术

Physics of Fluids Pub Date : 2025-01-01 Epub Date: 2025-01-10 DOI: 10.1063/5.0248257

Riley Vickers, Timothy M Weigand, Orlando Coronell, Cass T Miller

引用次数: 0

Characteristic evolution and energy variation during the generation of water droplet 水滴生成过程中的特征演化与能量变化

2区工程技术

Physics of Fluids Pub Date : 2024-12-01 DOI: 10.1063/5.0245127

Gaochao Pan, Bingyou Jiang, Chunshan Zheng, Xiaohan Wang, Yi Zhang, Jianqiang Yin, Hongzheng Zhu

{"title":"Characteristic evolution and energy variation during the generation of water droplet","authors":"Gaochao Pan, Bingyou Jiang, Chunshan Zheng, Xiaohan Wang, Yi Zhang, Jianqiang Yin, Hongzheng Zhu","doi":"10.1063/5.0245127","DOIUrl":"https://doi.org/10.1063/5.0245127","url":null,"abstract":"Understanding water droplet characteristic is an important prerequisite for improving wet dust removal efficiency. Using the high-speed camera system, the process of water droplet generation under the different Ca2+ concentrations and injecting velocities was studied. The width and length of water droplet increased, whereas the ratio of droplet width and length decreased with generation time. The water droplet generation time decreased with injecting velocity increasing, whereas kept almost unchanged with Ca2+ concentration. The equivalent diameter of droplet decreased with injecting velocity, whereas presented first a slight decrease and then a slight increase with Ca2+ concentration. This result suggested that the injecting velocity effect was stronger than the Ca2+ effect on the water droplet generation time and size. Furthermore, the effective injecting force and capillary force were mainly forces to influence the droplet generation in force analysis. RF (ratio of capillary force and effective pressure force) was first used to evaluate the synergistic effect of capillary force and effective injecting force. The greater RF, the water droplet generation time was longer and water droplet diameter was larger. Furthermore, the relationship between surface energy per unit (E/S) of water droplet and RF was a negative correlation. Those results can provide valuable suggestions to the development theory of dust removal.","PeriodicalId":20066,"journal":{"name":"Physics of Fluids","volume":"36 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147888990","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}

引用次数: 1

Shear flow at openings and hydrophobic sliding at gaps: A method for fabricating deformable microlenses by extracting cavities from a liquid bath 开口处的剪切流动和间隙处的疏水滑动：一种通过从液体浴液中提取空腔来制造可变形微透镜的方法

2区工程技术

Physics of Fluids Pub Date : 2024-12-01 DOI: 10.1063/5.0243283

Tongkai Gu, Niming Peng, Anjiang Cai, Lanlan Wang, Lei Yin, Hongzhong Liu

{"title":"Shear flow at openings and hydrophobic sliding at gaps: A method for fabricating deformable microlenses by extracting cavities from a liquid bath","authors":"Tongkai Gu, Niming Peng, Anjiang Cai, Lanlan Wang, Lei Yin, Hongzhong Liu","doi":"10.1063/5.0243283","DOIUrl":"https://doi.org/10.1063/5.0243283","url":null,"abstract":"A novel approach for fabricating deformable microlens arrays using template-induced self-assembly technology is introduced. By utilizing shear flow at cavity openings and hydrophobic sliding at interstitial gaps, this method achieves precise liquid microlens formation without the need for complex mechanical systems. The process employs a template immersed in a glycerol bath, where interfacial forces enable the pinning of liquid droplets within specific microcavities. A combination of theoretical modeling and finite element simulations was used to investigate the effects of cavity radius, pulling speed, and static contact angle on microlens liquid height. Findings reveal that larger cavity radii and higher static contact angles enhance liquid height. However, increased pulling speeds initially raise the liquid level before a subsequent decrease. Experimentally, uniform microlens arrays were successfully fabricated, demonstrating consistent surface shapes with the liquid level height of 43 μm and remarkable imaging tunability under thermal stimuli, achieving a 2.22-fold focal length expansion. This work advances the understanding of droplet manipulation and offers promising applications in microfluidics, optical systems, and surface engineering.","PeriodicalId":20066,"journal":{"name":"Physics of Fluids","volume":"36 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147902798","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}

引用次数: 0

A novel micromixer based on coastal fractal for manufacturing controllable size liposome 基于海岸分形的新型微混合器制备可控尺寸脂质体

2区工程技术

Physics of Fluids Pub Date : 2024-11-01 DOI: 10.1063/5.0239840

Xinkun Chen, Junlong Zhai, Xueye Chen

{"title":"A novel micromixer based on coastal fractal for manufacturing controllable size liposome","authors":"Xinkun Chen, Junlong Zhai, Xueye Chen","doi":"10.1063/5.0239840","DOIUrl":"https://doi.org/10.1063/5.0239840","url":null,"abstract":"The traditional lipid preparation methods are complex, time-consuming, and consume a large amount of reagents, increasing costs and difficulties. Although microfluidic technology is considered a promising solution, achieving controllable liposome production with a simple and inexpensive microfluidic mixing device remains an important problem. This paper presents a wall-type micro-mixer based on coastal zone fractals. Four parameters related to the geometric shape of the coastline fractal in the microchannel are used as design variables, and the mixing index is the objective function. Single-objective optimization numerical analysis of the primary wall-type fractal baffle micromixer under four Reynolds numbers conditions yields the optimal structural configuration. Visualization experiments verify the correctness and accuracy of the numerical simulation, and the optimized mixer is used to produce liposomes. The results show that the micro-mixer with the optimal double-sidewall cross arrangement enhances chaotic convection and improves mixing efficiency. At Re = 0.1 and Re = 100, the mixing efficiency reaches 99%, 50.44% higher than the reference design. By changing the relative flow rates of lipid and aqueous solutions, microfluidic blank liposomes with a particle size of 165.12 ± 11.6 nm and a polydispersity index of 0.35± are obtained. This wall-type fractal micro-mixer has broad application prospects due to its high mixing efficiency.","PeriodicalId":20066,"journal":{"name":"Physics of Fluids","volume":"36 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147917047","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}

引用次数: 41

The impact of blood viscosity modeling on computational fluid dynamic simulations of pediatric patients with Fontan circulation. 血液粘度建模对芳坦循环儿科患者计算流体动力学模拟的影响。

IF 4.3 2区工程技术

Physics of Fluids Pub Date : 2024-11-01 Epub Date: 2024-11-13 DOI: 10.1063/5.0236095

Heng Wei, Coskun Bilgi, Kellie Cao, Jon A Detterich, Niema M Pahlevan, Andrew L Cheng

{"title":"The impact of blood viscosity modeling on computational fluid dynamic simulations of pediatric patients with Fontan circulation.","authors":"Heng Wei, Coskun Bilgi, Kellie Cao, Jon A Detterich, Niema M Pahlevan, Andrew L Cheng","doi":"10.1063/5.0236095","DOIUrl":"10.1063/5.0236095","url":null,"abstract":"For univentricular heart patients, the Fontan circulation presents a unique pathophysiology due to chronic non-pulsatile low-shear-rate pulmonary blood flow, where non-Newtonian effects are likely substantial. This study evaluates the influence of non-Newtonian behavior of blood on fluid dynamics and energetic efficiency in pediatric patient-specific models of the Fontan circulation. We used immersed boundary-lattice Boltzmann method simulations to compare Newtonian and non-Newtonian viscosity models. The study included models from twenty patients exhibiting a low cardiac output state (cardiac index of 2 L/min/m2). We quantified metrics of energy loss (indexed power loss and viscous dissipation), non-Newtonian importance factors, and hepatic flow distribution. We observed significant differences in flow structure between Newtonian and non-Newtonian models. Specifically, the non-Newtonian simulations demonstrated significantly higher local and average viscosity, corresponding to a higher non-Newtonian importance factor and larger energy loss. Hepatic flow distribution was also significantly different in a subset of patients. These findings suggest that non-Newtonian behavior contributes to flow structure and energetic inefficiency in the low cardiac output state of the Fontan circulation.","PeriodicalId":20066,"journal":{"name":"Physics of Fluids","volume":"36 11","pages":"111911"},"PeriodicalIF":4.3,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11577338/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142688535","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}

引用次数: 0

A culling method for fluid–cloth interaction based on dual-scale dynamic time steps 基于双尺度动态时间步长的流布相互作用剔除方法

2区工程技术

Physics of Fluids Pub Date : 2024-10-01 DOI: 10.1063/5.0226993

Yanxia Jin, Songsong Wang, Keliang Nan, Ting Wang, Xinyu Liu, Zhuangwei Zhang, Xiaozhu Zhang

{"title":"A culling method for fluid–cloth interaction based on dual-scale dynamic time steps","authors":"Yanxia Jin, Songsong Wang, Keliang Nan, Ting Wang, Xinyu Liu, Zhuangwei Zhang, Xiaozhu Zhang","doi":"10.1063/5.0226993","DOIUrl":"https://doi.org/10.1063/5.0226993","url":null,"abstract":"This paper proposes a fluid–cloth simulation method based on dynamic time-stepping and a two-level collision detection algorithm to enhance the realism and real-time interaction of fluid and cloth. The method addresses the slow collision detection speed and poor culling efficiency between flexible cloth and complex fluid models. First, an adaptive k-means algorithm based on smoothed particle hydrodynamics is introduced, which dynamically divides fluid particles into two independent clusters according to velocity differences and applies a dual-scale dynamic time stepping (DDTS) scheme. Second, an extended position-based dynamics method is employed to simulate the cloth, integrating the small time steps derived from the fluid simulation to ensure the numerical stability during the cloth constraint solving process. Finally, a bounding box collision detection algorithm based on spatial hashing is constructed for the purpose of high-level culling between particles and triangles. At the low-level culling stage, a new filter, the dynamic motion filter (DMF), is proposed as a means of further improving culling efficiency. In comparison with the combination of continuous collision detection and position-based dynamics collision constraints, the average frame rate of the model building process with the introduction of the DDTS method is increased by 120%, resulting in higher-quality visual effects. Furthermore, the DMF increases the culling rate for vertex-face collision pairs by 3% to 23% and reduces overall collision detection time by 2% to 8% compared with other collision culling methods, enhancing the culling efficiency of collision.","PeriodicalId":20066,"journal":{"name":"Physics of Fluids","volume":"36 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147922524","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}

引用次数: 0