Microfluidics and Nanofluidics最新文献

{"title":"Development of 3D-structured tilt capillary valve for lab-on-a-disc devices","authors":"Yuito Murano,&nbsp;Shoji Yamamoto,&nbsp;Hayato Matsuzawa,&nbsp;Kazuhiro Morioka,&nbsp;Akihide Hemmi,&nbsp;Hizuru Nakajima","doi":"10.1007/s10404-025-02792-w","DOIUrl":"10.1007/s10404-025-02792-w","url":null,"abstract":"<div><p>Lab-on-a-disc (LoD) devices utilize centrifugal force to regulate fluid movement and are widely employed in biochemical applications. LoDs facilitate biochemical analysis by integrating different essential steps such as mixing samples and reagents, separating target components from the sample, and detecting analytes in a single platform. This integration on a single disc substrate enables the miniaturization and automation of various biochemical workflows. However, current LoD systems frequently rely on active valves, which increase complexity and limit versatility. To address these challenges, this study employed 3D printing technology to develop a 3D-structured tilt capillary valve acting as a passive control mechanism. Tilt capillary valves with inclination angles ranging from 50° to 80° were fabricated, and their burst rotational speeds and repeatability were compared with those of conventional capillary and slope valves. The tilt capillary valve demonstrated superior performance, achieving high-speed fluid control with relative standard deviations ranging from 1.5 to 2.1%. This improvement was attained by distributing the effects of centrifugal and gravitational forces along the inclined flow path. Additionally, the capillary structure stabilized the effects of surface tension, further enhancing reproducibility. These findings suggest that the developed tilt capillary valve enhances the LoD system performance, enabling more precise and rapid fluid control. The enhanced passive valve presented in this study can be implemented in advanced microfluidic device designs, presenting considerable potential for biochemical assays, point-of-care applications, environmental monitoring, and food safety testing.</p></div>","PeriodicalId":706,"journal":{"name":"Microfluidics and Nanofluidics","volume":"29 3","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10404-025-02792-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143446600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Advances in droplet microfluidics: a comprehensive review of innovations, morphology, dynamics, and applications","authors":"Sreeja Sadasivan,&nbsp;S. Pradeep,&nbsp;Jishnu Chandran Ramachandran,&nbsp;Jayaprakash Narayan,&nbsp;Michał Jan Gęca","doi":"10.1007/s10404-025-02789-5","DOIUrl":"10.1007/s10404-025-02789-5","url":null,"abstract":"<div><p>Droplet microfluidics is a rapidly evolving area of research with significant implications in bioengineering, drug delivery, chemical synthesis, environmental monitoring, and micro-scale electronics manufacturing. Recent advancements in droplet generation methods, including the use of electric fields and acoustic waves, have been driven by related technological developments. These innovations have enabled the creation of droplets with a wide range of sizes, shapes, and compositions, opening new frontiers for droplet microfluidic applications. This study reviews recent advances in droplet formation within microfluidic channels, beginning with an overview of droplet microfluidics and followed by an analysis of the various techniques used for droplet formation. The paper examines the impact of channel geometry, fluid flow rates, and channel wall surface properties on droplet formation. Additionally, it discusses the control of microfluidic droplets and the diverse applications of droplet microfluidics. The study also analyzes the morphological changes of droplets in response to variations in different controlling factors and presents an overview of compound droplet microfluidics, highlighting its technological aspects and significance across various applications. The influential factors governing the dynamics of compound droplets and their respective effects are briefly reviewed throughout the study. In conclusion, the paper identifies the major challenges and opportunities associated with microfluidic droplet dynamics and outlines emerging areas based on this technology. Overall, it provides a comprehensive overview of recent developments in droplet formation within microfluidic channels.</p></div>","PeriodicalId":706,"journal":{"name":"Microfluidics and Nanofluidics","volume":"29 3","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143438673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phage-displayed antibody fragments in microfluidic paper-based devices: a novel approach for sensitive detection of glycine-extended gastrin 17 biomarker using gold nanoparticles","authors":"Shokouh Jahedi,&nbsp;Mohammad Reza Tohidkia,&nbsp;Mahdad Esmaeili,&nbsp;Farhad Bani,&nbsp;Saeed Kaboli","doi":"10.1007/s10404-025-02791-x","DOIUrl":"10.1007/s10404-025-02791-x","url":null,"abstract":"<div><p>To evaluate the potential use of phage-displayed recombinant antibody fragments as biorecognition elements on microfluidic paper-based devices (µPADs), phage-displayed VL and soluble VL antibody fragments were immobilized on the chitosan-modified surface of µPADs to detect glycine-extended gastrin 17 (G17-Gly) an integral peptide biomarker for colorectal cancer. Additionally, the phage shaft displaying the scFv antibody fragment, used as a detection probe, was conjugated with gold nanoparticles (GNPs) and characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), and UV–visible spectroscopy (UV–Vis). Following the microfluidic sandwich immunoassay, the mean intensity of the color spots was quantitatively analyzed using an image analysis program. Peptide calibration curves showed a linear relationship between the intensity of the color spot signal and the logarithm of the peptide concentration within the ranges of 10⁻⁶–5 × 10⁻¹ µM (R² = 0.98) for the phage-VL fragment and 10⁻⁴–1 µM (R² = 0.97) for the soluble VL fragment, with limits of detection (LOD) of 0.9 and 29 pM, respectively. The proposed µPAD-based immunoassay with the desirable LODs without further amplification provides a simple, versatile means for detecting biomarkers and pathogens of interest.</p></div>","PeriodicalId":706,"journal":{"name":"Microfluidics and Nanofluidics","volume":"29 3","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143430806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 dynamic solidification of digital droplets and random behaviors during the recalescence process in a spiral-shaped milli-reactor","authors":"Yulin Wang,&nbsp;Z. L. Wang","doi":"10.1007/s10404-025-02790-y","DOIUrl":"10.1007/s10404-025-02790-y","url":null,"abstract":"<div><p>The freezing of droplets is a complex interdisciplinary research topic involving physics, chemistry, and computational science. This phenomenon has attracted considerable attention due to its significant applications in aerospace, meteorology, materials science, cryobiology, and pharmaceutical development. The development of microfluidic technology provides an ideal platform for microscopic physical research. In this study, we designed a spiral-shaped milli-reactor with a T-junction microchannel to generate digital droplets for studying and observing the digital freezing process of droplets. During the study of the recalescence and solidification processes of digital droplets dynamically moving in microchannels, we found that although the digital generation of droplets in our channel aligns well with the literature, achieving the digitalization of the droplet freezing process is very challenging. Even the initial phase of freezing (the recalescence process) exhibits significant randomness. A key feature of the randomness in the freezing process is the nucleation position of droplets within the channel, which significantly impacts the digital characteristics and hinders digital freezing. During the investigation of freezing randomness, we identified five distinct nucleation profiles, which largely determine the evolution of the freezing front and the duration of the recalescence phase. However, upon studying the motion velocity of the freezing front, we found that these velocities are temperature-dependent. This aligns with the results of our phase-field simulations and experimental findings, indicating that the release of latent heat during the recalescence process is stable. Additionally, the randomness in freezing may also stem from the deformation of droplets during the solidification process. In this study, we identified two distinct solidification modes during the freezing phase: one initiating from the droplet’s head or tail and the other starting from the middle, with the latter causing significant droplet deformation. Through statistical analysis, we further explored the influence of flow rate variation on the digital clustering of droplet freezing and discovered flow rate parameters that optimize freezing digitalization. For instance, when the oil phase flow rate is fixed, varying the water phase flow rate initially increases and then decreases the flatness factor, reaching a maximum at a water phase flow rate of <span>(Q_w = 0.5 , text {mL/min})</span>, indicating optimal clustering of droplets. The findings of this study provide new perspectives and approaches for controlling droplet freezing in microfluidic systems, while also offering significant insights into the unique behaviors and phenomena of nucleation and solidification processes at the microscale.</p></div>","PeriodicalId":706,"journal":{"name":"Microfluidics and Nanofluidics","volume":"29 3","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143423401","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heuristic modeling of material properties in Nano/Angstrom-scale channels: integrating experimental observations and MD simulations","authors":"Himanshu Mishra,&nbsp;Ashish Garg","doi":"10.1007/s10404-025-02788-6","DOIUrl":"10.1007/s10404-025-02788-6","url":null,"abstract":"<div><p>In this paper, we propose a unified framework to describe three key atomic-scale fluid properties-density, viscosity, and slip length-within nanoscale channels. These properties, which deviate significantly from bulk behavior, are expressed using simple power-law models as functions of the nanochannel height. The proposed framework accurately captures experimental and simulation data, providing a more flexible and interpretable alternative to existing complex or disparate models. The key advantage of our model lies in its mathematical properties. Continuity and a continuous derivative ensure seamless implementation into numerical simulations and theoretical predictions, leading to more understandable, stable, and accurate results. Additionally, the model adheres to physical principles, predicting convergence to bulk properties as channel size increases. Further, compared to existing exponential models, the unified power-law modeling approach offers several advantages. It provides flexibility by capturing nonlinear relationships and diverse data curvatures, interpretability through physically meaningful parameters, and adaptability for integration with other functions to model complex phenomena. Its simplicity facilitates easy parameter estimation, model interpretation, and computational efficiency. Moreover, its robustness makes it less sensitive to outliers and noise while maintaining fewer parameters that directly correspond to underlying physics and scaling laws. Hence, the proposed model’s simplicity, smoothness, physical validity, and generality establish it as a significant heuristic tool for the efficient design and optimization of nanoscale devices, utilizing theory and simulations across a wide range of applications.</p></div>","PeriodicalId":706,"journal":{"name":"Microfluidics and Nanofluidics","volume":"29 3","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143370043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comprehensive characterization of a microfluidic platform for DEP manipulation and bio-impedance detection using multi-sized polystyrene microbeads","authors":"Sameh Sherif,&nbsp;Yehya H. Ghallab,&nbsp;Yehea Ismail","doi":"10.1007/s10404-024-02785-1","DOIUrl":"10.1007/s10404-024-02785-1","url":null,"abstract":"&lt;div&gt;&lt;p&gt;Dielectrophoresis (DEP) manipulation combined with micro-electric impedance spectroscopy (µEIS) presents a sophisticated approach for cellular analysis and dielectric characterization. While conventional cell analysis techniques rely on complex labeling methods with inherent limitations, integrating DEP and µEIS offers non-invasive, label-free cellular characterization with enhanced sensitivity. This study presents an innovative dual-mode DEP platform incorporating both levitation (LEV&lt;sub&gt;DEP&lt;/sub&gt;) and rotational (ROT&lt;sub&gt;DEP&lt;/sub&gt;) forces, integrated with high-precision impedance measurement capabilities on one chip, enabling simultaneous Cell controlling and manipulation and dielectric signature extraction within a single microfluidic device. The fabricated and developed microfluidic platform demonstrated exceptional particle discrimination through the dual mode, with distinct responses for both particle populations. Under &lt;span&gt;(F_{lEV.DEP}^{10.4 mu m})&lt;/span&gt; 2.01 MHz showed a 63.4% magnitude increase, while &lt;span&gt;(F_{lEV.DEP}^{24.9 mu m })&lt;/span&gt; , particles exhibited a higher 81.2% increase at the same force, yielding a 2.48 × enhancement in discrimination ratio compared to no-DEP conditions. ROT&lt;sub&gt;DEP&lt;/sub&gt; at 110 kHz induced even more pronounced differences, with &lt;span&gt;(F_{ROT.DEP}^{10.4 mu m})&lt;/span&gt; showing a 120% magnitude increase (phase patterns: −24.501° to −34.363°) and &lt;span&gt;(F_{ROT.DEP}^{24.9 mu m})&lt;/span&gt; µm particles demonstrating a 145% increase (phase patterns: −31.267° to −42.891°), achieving a 3.16 × discrimination ratio enhancement. The impedance spectrum revealed distinct frequency-dependent signatures, with ROT&lt;sub&gt;DEP&lt;/sub&gt; showing superior mid-frequency discrimination (10.4 µm: 1.9370×&lt;span&gt;({10}^{4})&lt;/span&gt; Ω vs 24.9 µm: 2.0542×&lt;span&gt;({10}^{4})&lt;/span&gt; Ω at 110 kHz) and LEV&lt;sub&gt;DEP&lt;/sub&gt; optimizing high-frequency characterization (10.4 µm: 1.6677×&lt;span&gt;({10}^{4})&lt;/span&gt; Ω vs 24.9 µm: 1.5849×&lt;span&gt;({10}^{4})&lt;/span&gt; Ω at 2.01 MHz). These signatures demonstrate the platform’s comprehensive particle characterization capabilities through complementary DEP forces. The dual-mode approach enhanced discrimination ratios by 2.48 × under &lt;span&gt;(Lev. force)&lt;/span&gt; and 3.16 × under &lt;span&gt;(LEV. force)&lt;/span&gt; at selected characteristic frequency range compared to &lt;span&gt;(NonDEP force)&lt;/span&gt; conditions. Comprehensive impedance analysis through frequency spectrum (10 kHz—2.01 MHz) revealed unique frequency-dependent cell signatures, &lt;span&gt;(ROT. force)&lt;/span&gt; demonstrating superior mid-frequency discrimination (magnitude differences of 1.9370 × 10&lt;sup&gt;4&lt;/sup&gt; Ω vs 2.0542 × 10&lt;sup&gt;4&lt;/sup&gt; Ω at 110 kHz) and LEV&lt;sub&gt;DEP&lt;/sub&gt; optimizing high-frequency characterization (1.6677 × 10&lt;sup&gt;4&lt;/sup&gt; Ω vs 1.5849 × 10&lt;sup&gt;4&lt;/sup&gt; Ω at 2.01 MHz). Impedance dielectric analysis conducted over the 10 kHz to 2.01 MHz frequency range demonstrated frequency-dependent characteristics for each selected cell population. ROT&lt;sub&gt;DEP&lt;/sub&gt; enhanced","PeriodicalId":706,"journal":{"name":"Microfluidics and Nanofluidics","volume":"29 2","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10404-024-02785-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142995765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 novel approach to detect CD4 T-lymphocytes using a microfluidic chip and compact signal processing circuit","authors":"Huong Thi Phi,&nbsp;Phu Van Nguyen,&nbsp;Thanh Van Pham,&nbsp;Huy Van Hoang,&nbsp;Quynh Manh Luu,&nbsp;Thien Duy Nguyen,&nbsp;Huong Thi Thu Pham,&nbsp;Van Thi Thanh Nguyen,&nbsp;Luong Hoang Nguyen,&nbsp;Hong Thi Tran,&nbsp;Nam Hoang Nguyen","doi":"10.1007/s10404-024-02782-4","DOIUrl":"10.1007/s10404-024-02782-4","url":null,"abstract":"<div><p>CD4 T-lymphocytes (CD4 cells) are a type of T lymphocyte that plays an important role in the immune system, helping to fight germs and protect the body from disease. Accurate enumeration of CD4 T cells is crucial for assessing immune health and diagnosing various diseases. This study presents the development and validation of a novel microfluidic biochip system designed for the detection and counting of CD4 T cells using impedance measurements. The proposed system integrated a cell detection chip with a cost-effective signal processing circuit, which included an instrumental amplifier and a highly sensitive lock-in amplifier. The sensing structure, created using advanced microfabrication technology, consists of three microelectrodes and a 50 × 50 μm measurement aperture. The detection principle relied on the impedance imbalance caused by the presence of CD4 T cells in the fluidic flow between adjacent sensing electrodes. The system's performance was validated through extensive experiments, demonstrating high accuracy in detecting and counting CD4 T cells separated from whole blood based on their magnetic properties. The experimental results indicate that the proposed system was simpler, faster, and more cost-effective compared to traditional laser flow cytometry. Furthermore, the system’s portability and ease of use made it highly suitable for point-of-care diagnostics and on-site cell analysis. The utilization of microfabrication technology and impedance measurement not only enhanced efficiency and accuracy but also offered a reliable solution for rapid biological cell detection. Future work will focus on enhancing the throughput and miniaturizing the sensing structure to align with the high standards of conventional flow cytometry while maintaining cost-effectiveness and simplicity. This research lays a solid foundation for the development of advanced lab-on-a-chip technologies for biological cell detection and analysis, promising significant improvements in healthcare diagnostics and monitoring.</p></div>","PeriodicalId":706,"journal":{"name":"Microfluidics and Nanofluidics","volume":"29 2","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142905969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis and optimization of microfluidic systems for real-time detection of nutrients in soil based on computational fluid dynamics and response surface methodology","authors":"Sachin M. Khomane,&nbsp;Pradeep Vitthal Jadhav","doi":"10.1007/s10404-024-02781-5","DOIUrl":"10.1007/s10404-024-02781-5","url":null,"abstract":"<div><p>Microfluidics is turning out to be essential for the advancement of scientific research, healthcare, and various other applications due to its ability to provide precise control, miniaturization, and integration of fluid samples. Existing research shows a considerable growth rate in the utilization of microfluidics-based techniques, especially in the biomedical field for disease detection, drug analysis, cell analysis, and more. However, the development of microfluidic systems for soil nutrition testing applications is still a challenging task due to the need for micro scale dimensions and a high degree of precision during the fabrication and detection of soil nutrients. The present investigation aims to find the most suitable design for the microfluidic chip that can control and detect microfluid containing soil nutrients, especially nitrites, effectively. To achieve this goal, the parameters of different microchannel (MC) specimens, such as snug height, channel width, obstacle pitch, mean mixture pressure, wall shear stress, strain rate, and total pressure, are analyzed. In addition, the Response Surface Methodology (RSM) is introduced to statistically authenticate the obtained simulation data. As a result, the present investigation proposes the optimal MC design with optimal parameters: snug height of 0.35 mm, channel width of 1.54 mm, obstacle pitch of 2.5 mm, mean mixture pressure of 0.24 MPa, wall shear stress of 1.1 Pa, strain rate of 2259 s⁻¹, and total pressure of 1.42 MPa. Moreover, the functionality of the proposed microfluidic chip was calibrated and predicted using the Deep Neural Network-based Modified Sea Horse Optimizer (DNN-MSHO) algorithm, confirming the presence of nitrites in the used soil samples in a range of 2.81–4.18 ppm, which again proves the efficiency and trustworthiness of the proposed microfluidic chip design and its usability in real soil testing applications.</p></div>","PeriodicalId":706,"journal":{"name":"Microfluidics and Nanofluidics","volume":"29 2","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142890073","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shapes of surfactant-laden Taylor bubbles in a square microchannel","authors":"Ryota Igarashi,&nbsp;Riku Hachikubo,&nbsp;Ryo Kurimoto,&nbsp;Kosuke Hayashi","doi":"10.1007/s10404-024-02784-2","DOIUrl":"10.1007/s10404-024-02784-2","url":null,"abstract":"<div><p>Experiments on contaminated Taylor flows in a square microchannel were carried out to investigate the effects of surfactant on the bubble shape in the nose and tail regions for different surfactant properties. The nose curvature was found to be proportional to the bubble length at low surfactant concentrations, while it was independent of the concentration at high concentrations. The rate of increase in the nose curvature at the former concentrations can be expressed in terms of the surface coverage ratio. The bubble velocity decreased with increasing the nose curvature, whereas the surface tension reduced by surfactant adsorption worked better to correlate the velocity data. The curvature of the bubble tail increased steeply at low concentrations as a consequence of the early coverage due to interfacial advection. The tail curvature also had a strong correlation with the surface coverage ratio.</p></div>","PeriodicalId":706,"journal":{"name":"Microfluidics and Nanofluidics","volume":"29 2","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10404-024-02784-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142890074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Envelope boundary conditions for the upper surface of two-dimensional canopy interacting with fluid flow","authors":"Shota Akita,&nbsp;Kie Okabayashi,&nbsp;Shintaro Takeuchi","doi":"10.1007/s10404-024-02779-z","DOIUrl":"10.1007/s10404-024-02779-z","url":null,"abstract":"<div><p>Boundary conditions at the surface of a layer of flexible fibers (i.e. the canopy envelope) subjected to fluid flow are proposed for uniform and non-uniform motions of the fibers, where the fibers exhibit identical and individual motions, respectively, to understand the mechanisms of the swaying motion of the canopy. By assuming small deflections, the fibers are treated as rigid rods hinged to a flat wall and the effects of the hydrodynamic force on the fibers are expressed with the moment of fluid forces by averaging the Navier–Stokes equations. For the uniformly moving case, displacement of the envelope is represented by a mass-spring-damper system driven by the hydrodynamic force. As the non-uniformity of the canopy behavior enhances, the effects of the diffusion of fiber velocities and fluid inertia along the fiber stems play a more important role in the envelope displacement equation. Numerical simulations of fluid flow are conducted with the envelope displacement models as the boundary conditions at the canopy surface. The validity of the present models is assessed by comparison with the results of fluid–structure interaction (FSI) simulation, which directly solves the interaction between individual fibers and fluid by an immersed boundary method. With the envelope model for non-uniform displacement, the grid convergence of the numerical result is about a first order rate. The comparison of the terms in the envelope model for non-uniform displacement shows that diffusion of fiber velocities dominates the motion of fibers. The applicability of the model is assessed by varying the number density of the fibers.</p></div>","PeriodicalId":706,"journal":{"name":"Microfluidics and Nanofluidics","volume":"29 2","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142889560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}