Article
Chemistry, Physical
Seokgyun Ham, Wen-Zhen Fang, Rui Qiao
Summary: The actuation of ferromagnetic particles confined in microchannels was studied using lattice Boltzmann simulations, revealing different trends in actuation force based on the proximity to the channel walls and the channel width. The analysis of flow and pressure fields in the system helped in understanding the hydrodynamic forces acting on the particles.
Article
Chemistry, Physical
Mahmud Kamal Raihan, Sen Wu, Heston Dort, Micah Baghdady, Yongxin Song, Xiangchun Xuan
Summary: The effect of changing the depth of contraction-expansion microchannels on the flow responses of three types of polymer solutions and water was investigated. The flow of viscoelastic polyethylene oxide (PEO) solution became more stable in the contraction part while being less stable in the expansion part with the increase of the channel depth. In contrast, the entire flow became less stable in deeper channels for the shear-thinning xanthan gum (XG) solution as well as the shear thinning and viscoelastic polyacrylamide (PAA) solution.
Article
Chemistry, Physical
Kirill A. Komarov, Vladimir N. Mantsevich, Stanislav O. Yurchenko
Summary: This study investigates the tunable interactions between composite particles with core-shell structure in a rotating electric field, showing that engineering the internal structure provides an effective tool for designing interactions. By generalizing an integral theory, the study reveals the main trends in interactions influenced by the structure.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Thermodynamics
Congcong Ren, Wenming Li, Jiaxuan Ma, Guanghan Huang, Chen Li
Summary: This study focuses on enhancing flow boiling performance in microchannels without using inlet restrictors, by fabricating parallel microgrooves on the bottom surface of the channels. The microgrooves effectively manage two-phase flow instabilities and enable high-frequency rewetting, enhancing heat transfer rates and delaying critical heat flux conditions. Through visualization studies, it was found that the microgrooves can significantly improve thin film evaporation and overall heat transfer coefficients in the microchannels.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Qun Han, Zhaoxuan Liu, Yongping Chen, Wenming Li
Summary: In this study, a novel tesla-type copper microchannel configuration was explored to inhibit vapor backflow and promote two-phase transport simultaneously in the forward direction. The effect of this configuration on two-phase mixing in the backward direction was also investigated. Experimental results show that both critical heat flux (CHF) and heat transfer coefficient (HTC) are significantly increased due to the effective suppression of vapor backflow and enhanced two-phase mixing. At a mass velocity of 360 kgm-2 s-1, CHF and HTC increase by 88.4% and 86.8% respectively.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Engineering, Chemical
Rafael L. Rangel, Francisco Kisuka, Colin Hare, Vincenzino Vivacqua, Alessandro Franci, Eugenio Onate, Chuan-Yu Wu
Summary: Granular flow in industrial applications involves heat generation from frictional contacts and collisions between particles. This study explores the temperature rise of granular flows in a rotating drum for the first time, using infrared thermography to quantify the temperature changes. The experiments show that particles with higher density generate more heat and increasing rotation speed favors temperature rise, while fill ratio has the least influence on thermal response.
Article
Engineering, Chemical
Yan Pang, Yao Lu, Xiang Wang, Qiang Zhou, Yanlin Ren, Zhaomiao Liu
Summary: Experimental study was conducted on bubble size in T-junction microchannels under pressure-driven conditions, showing that bubble length increases with flow rate and driving pressure. Different downstream channel types directly influence bubble size by affecting resistance, with a nonlinear relationship observed between them. Adjustment of flow rate at downstream provides feedback to bubble generation in the double T-junction channel.
CHEMICAL ENGINEERING SCIENCE
(2021)
Article
Thermodynamics
Yusi Tian, Yonggang Jiao, Fei Han, Zuo Cheng, Jian Li
Summary: In this paper, the structure of the interrupted microchannel is improved by numerical simulation, and the two-phase characteristics of the new microchannel are quantified using gas-liquid flow ratios, relative standard deviations, and pressure drop fluctuations. The simulation results show that the widening design of the two side branches offsets the effect of inertia force and balances the flow resistance in the downstream branches. The gas flow relative standard deviation of the interrupted microchannel is significantly lower than that of the traditional microchannel at high void fraction.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Multidisciplinary Sciences
Ranabir Dey, Carola M. Buness, Babak Vajdi Hokmabad, Chenyu Jin, Corinna C. Maass
Summary: Researchers demonstrate the regular, controllable, and reproducible oscillatory rheotaxis in artificial microswimmers. The oscillatory rheotaxis of a self-propelling droplet in a microchannel is primarily governed by shear flow characteristics and the interaction of the finite-sized microswimmer with microchannel walls. These findings provide a realistic understanding of the behavior of active particles in confined microflows, which is relevant in many biotechnology applications.
NATURE COMMUNICATIONS
(2022)
Article
Mechanics
Di Li, Le Song, Cheng Zhang, Liandong Yu, Xiangchun Xuan
Summary: The study developed a depth-averaged inertial flow model for Newtonian fluids in shallow microchannels, which was assessed for its validity and accuracy through comparisons with experimental measurements and three-dimensional numerical simulations. The proposed depth-averaged model provides similar accuracy to three-dimensional modeling when the channel depth-to-width ratio is small.
Article
Physics, Fluids & Plasmas
F. Mignolet, A. Darras, G. Lumay
Summary: When subjected to an external magnetic field, 2D layers of superparamagnetic colloids form specific structures, such as chains and disklike clusters. It was observed that the colloids aggregate into rotating chains before clustering into disklike structures. Over time, these chains interact with each other and aggregate into disklike clusters.
Article
Chemistry, Multidisciplinary
Zhongdong Wang, Xingyu Xiang, Sajawal Raza, Asad Ullah, Chunying Zhu, Tianyang Feng, Youguang Ma, Taotao Fu
Summary: This paper investigates the emulsification process and numbering-up of droplets in asymmetric parallelized microchannels with T-junction. It analyzes the effects of fluid properties and operating conditions on droplet size. The paper also examines the flow patterns of droplet swarm in cavities and their influence on fluid distribution. It proposes a droplet size prediction equation and fluid distribution model, and investigates the phenomenon of droplet asynchronous generation and its effect on droplet monodispersity, suggesting a method for prevention.
JOURNAL OF FLOW CHEMISTRY
(2023)
Article
Engineering, Chemical
Saebom Lee, Jihyeong Lee, Minki Lee, Hyejeong Kim, Gyoujin Cho, Jinkee Lee
Summary: This study numerically investigated the mixing performance of a rotating channel based on the Coriolis force with herringbone grooves. Mixing was maximized when the Coriolis force was appropriately balanced with the centrifugal force. The addition of herringbone grooves improved mixing, achieving up to >90% for the shortest channel length.
CHEMICAL ENGINEERING SCIENCE
(2024)
Article
Multidisciplinary Sciences
Florian Katzmeier, Friedrich C. Simmel
Summary: This study investigates the second-order electrokinetic flow caused by concentration polarization electro-osmosis (CPEO) around colloidal particle dimers. The researchers demonstrate the controllable manipulation and assembly of charged dielectric particles by controlling the orientation of the AC electric field. The experimental results provide parameter ranges for the operation of microrobots and indicate that CPEP is a generic phenomenon.
NATURE COMMUNICATIONS
(2023)
Article
Multidisciplinary Sciences
Weiyue Xin, Hao Wu, Gregory M. Grason, Maria M. Santore
Summary: By manipulating the curvature in an elastic fluid lamella, researchers were able to adjust the relative positions of micrometer-scale inclusions. The interactions between solid domain pairs in a fluid membrane were studied, showing attractions and repulsions that are switchable. The effect of vesicle inflation on domain separation was consistent regardless of the number of domains present in the vesicles.
Article
Chemistry, Physical
Judit Clopes, Gerhard Gompper, Roland G. Winkler
Summary: This study investigates the properties of microswimmer dumbbells consisting of pusher-puller pairs using mesoscale hydrodynamic simulations. The simulations reveal that the flow fields of the squirmers strongly influence the orientation of their propulsion directions, fluctuations, and swimming behavior. The magnitude of the active stresses only weakly affects the properties of pusher-puller pairs with equal stress magnitudes, but for non-equal stress magnitudes, strong orientational correlations are observed. The active motion of the dumbbells is influenced by these correlations, with faster motion for strong pushers and slower motion for strong pullers.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Physics, Multidisciplinary
Alexis Darras, Anil Kumar Dasanna, Thomas John, Gerhard Gompper, Lars Kaestner, Dmitry A. Fedosov, Christian Wagner
Summary: The erythrocyte sedimentation rate is a long-established medical diagnostic method, but its physical mechanisms are still debated. Through microscopy and cell-level simulations, we found that erythrocytes form a soft-particle gel, exhibiting unique properties due to the high volume fraction, deformability, and weak attraction among the cells. We developed a theoretical model for gravitational collapse, which was validated by detailed macroscopic measurements of interface velocity.
PHYSICAL REVIEW LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Jiarul Midya, Thorsten Auth, Gerhard Gompper
Summary: Transport of particles across lipid-bilayer membranes is crucial for cells to interact with their environment. While previous studies have focused on hard particles, this research investigates the wrapping process for deformable particles, specifically vesicles. The findings highlight the importance of particle softness in determining the stability and interaction behavior of wrapped vesicles, providing insights for the design of deformable particles for medical applications.
Article
Physics, Multidisciplinary
Marielle Gassner, Segun Goh, Gerhard Gompper, Roland G. Winkler
Summary: This study theoretically and through simulations analyzes the properties of a cognitive, self-propelled, and self-steering particle in the presence of a stationary target, with a focus on the competition between confinement, activity, and steering. The pursuer is modeled as an intelligent active Ornstein-Uhlenbeck particle (iAOUP) confined in a harmonic potential. Universal scaling regimes for the pursuer-target distance are found for the free pursuer, with the Pe'clet number and maneuverability as key factors. Steering leads to a constant mean-distance regime that widens with increasing maneuverability. Confinement strongly impacts propulsion direction and results in scaling behaviors similar to those without confinement but dependent on confinement strength at large Pe'clet numbers.
Article
Multidisciplinary Sciences
Xiaoyan Liu, Thorsten Auth, Nabanita Hazra, Morten Frend Ebbesen, Jonathan Brewer, Gerhard Gompper, Jerome J. Crassous, Emma Sparr
Summary: This paper investigates how the wrapping of colloidal particles by lipid membranes can be controlled by various factors such as particle shape, particle-membrane adhesion energy, membrane phase behavior, and membrane-bending rigidity. The study shows that ellipsoidal microgel particles are more likely to form deep-wrapped states compared to spherical particles. The findings have implications for the design of novel biomaterials and therapeutic applications involving nanoparticle-membrane interactions.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Physics, Multidisciplinary
Segun Goh, Roland G. Winkler, Gerhard Gompper
Summary: This study investigates the pursuit behavior of pursuer-target pairs with implicit sensing mechanism and limited hydrodynamic steering abilities of the pursuer. The findings suggest that stable cooperatively moving states can be achieved depending on the nature of the microswimmer propulsion and the velocity-adaptation scheme.
COMMUNICATIONS PHYSICS
(2023)
Article
Chemistry, Physical
Priyanka Iyer, Gerhard Gompper, Dmitry A. Fedosov
Summary: Recent advances in micro- and nano-technologies have made it possible to construct complex active systems using biological and synthetic materials. This study investigates the behavior of active vesicles, which are composed of a membrane enclosing self-propelled particles and exhibit characteristics similar to biological cells. The adhesion of self-propelled particles to the membrane significantly influences the shape and dynamics of the vesicles, providing an additional parameter for controlling their behavior.
Article
Physics, Multidisciplinary
Joscha Mecke, Yongxiang Gao, Carlos A. Ramirez Medina, Dirk G. A. L. Aarts, Gerhard Gompper, Marisol Ripoll
Summary: This article reports the simultaneous occurrence and relation of two seemingly separate phenomena: active turbulence and odd viscosity, in a chiral active fluid composed of standing and spinning colloidal rods and in simulations for synchronously rotating hard discs in a hydrodynamic explicit solvent.
COMMUNICATIONS PHYSICS
(2023)
Article
Multidisciplinary Sciences
Yunfei Huang, Youssef Mabrouk, Gerhard Gompper, Benedikt Sabass
Summary: Automatic machine learning of empirical models from experimental data has become possible and efficient. The method achieves superior accuracy and robustness in inferring governing differential equations, including ordinary, partial, and stochastic ones. Furthermore, an active learning procedure is developed for discovering stochastic differential equations and improving the inference of global models.
SCIENTIFIC REPORTS
(2022)
Correction
Chemistry, Physical
Priyanka Iyer, Gerhard Gompper, Dmitry A. A. Fedosov
Article
Chemistry, Physical
Priyanka Iyer, Gerhard Gompper, Dmitry A. Fedosov
Summary: This study investigates the behavior of active vesicles through simulations, analyzing the deformations of membranes, clustering and mobility of SPPs. The results reveal a feedback mechanism between membrane curvature, particle clustering, and changes in vesicle shape due to SPP activity.
Article
Chemistry, Physical
Rajendra Singh Negi, Roland G. Winkler, Gerhard Gompper
Summary: This study investigates self-steering active Brownian particle systems through simulations and discovers self-organized large-scale structures that depend on parameter values and excluded-volume interactions. The analysis of particle dynamics reveals ABP-like behaviors in dilute systems and the worm phase. In densely packed structures, the active diffusion coefficient is significantly smaller and depends on the number of particles in the cluster. The study also explores the interplay between ABP-characteristic interactions and cognitive-based interactions and navigation.
Article
Physics, Fluids & Plasmas
Christian A. Philipps, Gerhard Gompper, Roland G. Winkler
Summary: Analytical investigation of isolated semiflexible active polar ring polymers reveals that activity does not affect ring conformations but strongly impacts internal dynamics, showing characteristic time regimes that are absent in passive rings. Flexible rings exhibit activity-enhanced diffusive behavior on intermediate timescales, while semiflexible rings display ballistic motion. Additionally, a second active time regime emerges on longer timescales, with rings showing snake-like motion reminiscent of tank-treading rotational dynamics in shear flow.
Article
Physics, Fluids & Plasmas
Anil Kumar Dasanna, Alexis Darras, Thomas John, Gerhard Gompper, Lars Kaestner, Christian Wagner, Dmitry A. Fedosov
Summary: The erythrocyte sedimentation rate is commonly used as an indicator of cell aggregation and inflammation. This study investigated the relationship between fibrinogen concentration, microstructure of erythrocyte suspension, and erythrocyte sedimentation rate. The researchers found that an increase in attraction strength between cells led to a cell network with larger void spaces, resulting in faster sedimentation. These findings support the gel hypothesis in blood sedimentation interpretation.
Article
Physics, Fluids & Plasmas
Judit Clopes Llahi, Aitor Martin-Gomez, Gerhard Gompper, Roland G. Winkler
Summary: This study compares the properties of self-propelled and externally actuated active Brownian polymers in a fluid. By implementing a multiparticle collision (MPC) simulation, the conformational and dynamical properties of the active polymers, as well as their scaling behavior with respect to wave number and time dependence, are obtained. The suitability of the implementation is confirmed by comparing the simulation results with theoretical predictions.
