Physical Review Fluids最新文献_第5页

Effects of initial packing density and cohesion on submerged granular collapse 初始堆积密度和内聚力对水下颗粒塌陷的影响

IF 2.7 3区物理与天体物理

Physical Review Fluids Pub Date : 2024-08-20 DOI: 10.1103/physrevfluids.9.084302

Rui Zhu, Zhiguo He, Eckart Meiburg

引用次数: 0

Convection in the active layer speeds up permafrost thaw in coarse-grained soils 活动层中的对流加速了粗粒土壤中永久冻土的融化

IF 2.7 3区物理与天体物理

Physical Review Fluids Pub Date : 2024-08-19 DOI: 10.1103/physrevfluids.9.l081501

M. Magnani, S. Musacchio, A. Provenzale, G. Boffetta

引用次数: 0

Droplet impact on rotating surfaces: The effect of centrifugal force and wettability on spreading dynamics 旋转表面上的液滴冲击：离心力和润湿性对扩散动力学的影响

IF 2.7 3区物理与天体物理

Physical Review Fluids Pub Date : 2024-08-19 DOI: 10.1103/physrevfluids.9.083605

Dongdong Liu, Hongdong Yin, Zeyu Wu, Xiang Luo

{"title":"Droplet impact on rotating surfaces: The effect of centrifugal force and wettability on spreading dynamics","authors":"Dongdong Liu, Hongdong Yin, Zeyu Wu, Xiang Luo","doi":"10.1103/physrevfluids.9.083605","DOIUrl":"https://doi.org/10.1103/physrevfluids.9.083605","url":null,"abstract":"Droplet impact on rotating surfaces experiences the tangential shear force from the rotating surface, generating a centrifugal force that either enhances the spreading or destabilizes the expanding lamella. In this study, we experimentally characterize the impact of a water droplet on rotating surfaces with various wettabilities, and theoretically analyze the observed impacting dynamics, including the enhanced spreading and the transition to the destabilization of the expanding lamella. Liquids with a wide range of viscosity are tested to explore the effect of liquid viscosity on the impacting dynamics. We propose a simplified approach to predict the tangential velocity induced by the surface's tangential shear force, and validate the predicted velocity by flow field measurement. We further deduce a quantitative description for the maximum spreading factor in the spreading regime, and derive the critical condition for the destabilization of the lamella for a water droplet. Good agreements are found between the predicted values and the measured ones for the impact on the rotating surfaces with various wettabilities.","PeriodicalId":20160,"journal":{"name":"Physical Review Fluids","volume":"16 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Data-driven low-dimensional model of a sedimenting flexible fiber 数据驱动的沉积柔性纤维低维模型

IF 2.7 3区物理与天体物理

Physical Review Fluids Pub Date : 2024-08-16 DOI: 10.1103/physrevfluids.9.084101

Andrew J. Fox, Michael D. Graham

{"title":"Data-driven low-dimensional model of a sedimenting flexible fiber","authors":"Andrew J. Fox, Michael D. Graham","doi":"10.1103/physrevfluids.9.084101","DOIUrl":"https://doi.org/10.1103/physrevfluids.9.084101","url":null,"abstract":"The dynamics of flexible filaments entrained in flow, important for understanding many biological and industrial processes, are computationally expensive to model with full physics simulations. In this paper, we describe a data-driven technique to create high-fidelity low-dimensional models of flexible fiber dynamics using machine learning; the technique is applied to sedimentation in a quiescent, viscous Newtonian fluid, using results from detailed simulations as the dataset. The approach combines an autoencoder neural network architecture to learn a low-dimensional latent representation of the filament shape, with a neural ordinary differential equation that learns the evolution of the particle in the latent state. The model was designed to model filaments of varying flexibility, characterized by an elastogravitational number <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi mathvariant=\"script\">B</mi></math>, and was trained on a dataset containing the evolution of fibers beginning at set angles of inclination. For the range of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi mathvariant=\"script\">B</mi></math> considered here (100–10 000), the filament shape dynamics can be represented with high accuracy with only four degrees of freedom, in contrast with the 93 present in the original bead-spring model used to generate the dynamic trajectories. We predict the evolution of fibers set at arbitrary angles and demonstrate that our data-driven model can accurately forecast the evolution of a fiber at both trained and untrained elastogravitational numbers.","PeriodicalId":20160,"journal":{"name":"Physical Review Fluids","volume":"30 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Flooding as a sub-critical instability in open channels 洪水是明渠中的次临界不稳定因素

IF 2.7 3区物理与天体物理

Physical Review Fluids Pub Date : 2024-08-15 DOI: 10.1103/physrevfluids.9.084607

Serge Mora, Martine Le Berre, Yves Pomeau

引用次数: 0

Coupling atomization, emulsification, and polymerization steps for creating gel microspheres 将雾化、乳化和聚合步骤耦合在一起以制造凝胶微球

IF 2.7 3区物理与天体物理

Physical Review Fluids Pub Date : 2024-08-15 DOI: 10.1103/physrevfluids.9.083604

S. Danial Naghib, Matin Mirbaha, Kristina Logushkova, Jérôme Bibette, Nicolas Bremond

引用次数: 0

Maintenance mechanism of a circular surface wave in a magnetohydrodynamic cell and limits of its existence 磁流体动力学单元中圆周表面波的维持机制及其存在极限

IF 2.7 3区物理与天体物理

Physical Review Fluids Pub Date : 2024-08-15 DOI: 10.1103/physrevfluids.9.083702

Vladislav Eltishchev, Gennadiy Losev, Peter Frick

{"title":"Maintenance mechanism of a circular surface wave in a magnetohydrodynamic cell and limits of its existence","authors":"Vladislav Eltishchev, Gennadiy Losev, Peter Frick","doi":"10.1103/physrevfluids.9.083702","DOIUrl":"https://doi.org/10.1103/physrevfluids.9.083702","url":null,"abstract":"The circular surface wave (CSW) of a low-temperature gallium alloy in the immovable cell with a central bottom electrode and an upper ring electrode exposed to axial magnetic fields is studied experimentally. It is shown that, depending on the force parameter and geometrical characteristics of the cell [cell radius, height of the liquid metal (LM) layer, and position of the circular electrode], three modes can occur in the cell: rest, CSW, or axial rotation with a deep funnel on the surface providing the circular contact of the LM with the electrode. A mode map showing the boundaries of the CSW existence domain is plotted on the parameter plane. The mechanism which provides the existence of a stable CSW is suggested. It is shown that the CSW is a superposition of two intense large-scale vortices. The main vortex, whose axis coincides with the axis of the cylindrical cell, is generated by the Lorentz force localized near the bottom electrode and arising from the interaction of the divergent electric current with the vertical magnetic field. The intensity of the second vortex is an order of magnitude less, and the axis of rotation is directed to the contact area of the liquid metal with the ring electrode, which appears near the crest of the wave. Similar to the main vortex, it exists due to the interaction of the current converging to the contact area with the superimposed magnetic field. The second vortex provides the lifting of the LM ahead of the incoming wave. The intensity of both vortices is proportional to the product of the external field by the total current, which explains the linear relationship between the relative frequency of surface oscillations and their amplitude.","PeriodicalId":20160,"journal":{"name":"Physical Review Fluids","volume":"406 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Confinement induced three-dimensional trajectories of microswimmers in rectangular channels 矩形水道中微游子的密闭诱导三维轨迹

IF 2.7 3区物理与天体物理

Physical Review Fluids Pub Date : 2024-08-14 DOI: 10.1103/physrevfluids.9.083302

Byjesh N. Radhakrishnan, Ahana Purushothaman, Ranabir Dey, Sumesh P. Thampi

{"title":"Confinement induced three-dimensional trajectories of microswimmers in rectangular channels","authors":"Byjesh N. Radhakrishnan, Ahana Purushothaman, Ranabir Dey, Sumesh P. Thampi","doi":"10.1103/physrevfluids.9.083302","DOIUrl":"https://doi.org/10.1103/physrevfluids.9.083302","url":null,"abstract":"We study the trajectories of a model microorganism inside three-dimensional channels with square and rectangular cross sections. Using (1) numerical simulations based on the lattice-Boltzmann method and (2) analytical expressions using far-field hydrodynamic approximations and the method of images we systematically investigate the role of the strength and finite-size of the squirmer, confinement dimensions, and initial conditions in determining the three-dimensional trajectories of microswimmers. Our results indicate that the hydrodynamic interactions with the confining walls of the channel significantly affect the swimming speed and trajectory of the model microswimmer. Specifically, pullers always display sliding motion inside the channel: weak pullers slide through the channel center line, while strong pullers slide through a path close to any of the walls. Pushers generally follow helical motion in a square channel. Unlike pullers and pushers, the trajectories of neutral swimmers are not easy to generalize and are sensitive to the initial conditions. Despite this diversity in the trajectories, the far-field expressions capture the essential features of channel-confined swimmers. Finally, we propose a method based on the principle of superposition to understand the origin of the three-dimensional trajectories of channel confined swimmers. Such construction allows us to predict and justify the origin of apparently complex three-dimensional trajectories generated by different types of swimmers in channels with square and rectangular cross sections.","PeriodicalId":20160,"journal":{"name":"Physical Review Fluids","volume":"19 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Numerical investigation on the heat transfer in wind turbulence over breaking waves 破浪风湍流传热数值研究

IF 2.7 3区物理与天体物理

Physical Review Fluids Pub Date : 2024-08-14 DOI: 10.1103/physrevfluids.9.084606

Min Lu, Zixuan Yang, Guowei He, Lian Shen

{"title":"Numerical investigation on the heat transfer in wind turbulence over breaking waves","authors":"Min Lu, Zixuan Yang, Guowei He, Lian Shen","doi":"10.1103/physrevfluids.9.084606","DOIUrl":"https://doi.org/10.1103/physrevfluids.9.084606","url":null,"abstract":"Heat transfer in wind turbulence over breaking waves is studied through direct numerical simulations. The air-water system is simulated on an Eulerian grid with the interface between the two phases captured by a coupled level set and volume-of-fluid method. To examine the effect of wave age, different cases representing slow, intermediate, and fast waves are considered for the scenario of air temperature being higher than the water temperature. The results show that the evolution of mean temperature profile responds nonmonotonically to the increasing wave age. At a small wave age, the mean temperature near the water surface increases after wave breaking. At intermediate and large wave ages, however, the temperature decreases after wave breaking, while the decrement magnitude is larger at the intermediate wave age. An investigation of the temperature fluctuation flux indicates that a combined effect of wave-coherent flux and turbulence-induced flux leads to a large magnitude of temperature decrement at the intermediate wave age. A further analysis of the production term in the transport equation of the turbulence-induced temperature flux elucidates the mechanism underlying the generation of the turbulence-induced flux at the intermediate wave age. The findings of the present study suggest that temperature responds in a more complex manner to wave age than velocity does and this phenomenon should be considered in models for air-sea interaction and weather forecasting.","PeriodicalId":20160,"journal":{"name":"Physical Review Fluids","volume":"3 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142227808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Droplet breakup and size distribution in an airstream: Effect of inertia 气流中的液滴破裂和大小分布：惯性的影响

IF 2.7 3区物理与天体物理

Physical Review Fluids Pub Date : 2024-08-13 DOI: 10.1103/physrevfluids.9.084004

Someshwar Sanjay Ade, Pavan Kumar Kirar, Lakshmana Dora Chandrala, Kirti Chandra Sahu

{"title":"Droplet breakup and size distribution in an airstream: Effect of inertia","authors":"Someshwar Sanjay Ade, Pavan Kumar Kirar, Lakshmana Dora Chandrala, Kirti Chandra Sahu","doi":"10.1103/physrevfluids.9.084004","DOIUrl":"https://doi.org/10.1103/physrevfluids.9.084004","url":null,"abstract":"We experimentally investigate the morphology and breakup of a droplet as it descends freely from a height and encounters an airstream. The size distributions of the child droplets are analyzed using high-speed shadowgraphy and in-line holography techniques. We find that a droplet falling from various heights exhibits shape oscillations due to the intricate interplay between inertia and surface tension forces, leading to significant variations in the radial deformation of the droplet, influencing the breakup dynamics under an identical airstream condition. Specifically, the droplet undergoes vibrational breakup when introduced at a location slightly above the air nozzle. In contrast, as the release height of the droplet increases, keeping the Weber number defined based on the velocity of the airstream fixed, a dynamic interplay between the inertia of the droplet and the aerodynamic flow field comes into play, resulting in a sequence of breakup modes transitioning from vibrational breakup to retracting bag breakup, bag breakup, bag-stamen breakup, retracting bag-stamen breakup, and eventually returning to vibrational breakup. Our experiments also reveal that the size distribution resulting from retracting bag breakup primarily arises from rim and node fragmentation, leading to a bimodal distribution. In contrast, bag and bag-stamen breakups yield a trimodal size distribution due to the combined contributions of bag, rim, and node breakup mechanisms. Furthermore, we utilize a theoretical model that incorporates the effective Weber number, considering different release heights. This model accurately predicts the size distribution of the child droplets resulting from the various breakup modes observed in our experiments.","PeriodicalId":20160,"journal":{"name":"Physical Review Fluids","volume":"55 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0