Physical Review Fluids最新文献_第5页

Translation of a sphere towards a rigid plane in an Oldroyd-B fluid 球体在奥尔德罗伊德-B 流体中向刚性平面的平移

IF 2.7 3区物理与天体物理

Physical Review Fluids Pub Date : 2024-08-21 DOI: 10.1103/physrevfluids.9.083303

Tachin Ruangkriengsin, Rodolfo Brandão, Bimalendu Mahapatra, Evgeniy Boyko, Howard A. Stone

{"title":"Translation of a sphere towards a rigid plane in an Oldroyd-B fluid","authors":"Tachin Ruangkriengsin, Rodolfo Brandão, Bimalendu Mahapatra, Evgeniy Boyko, Howard A. Stone","doi":"10.1103/physrevfluids.9.083303","DOIUrl":"https://doi.org/10.1103/physrevfluids.9.083303","url":null,"abstract":"We analyze the low-Reynolds-number translation of a sphere towards or away from a rigid plane in an Oldroyd-B fluid under two scenarios: prescribing the sphere's translational velocity, and prescribing the force on the sphere. Leveraging the lubrication approximation and a perturbation expansion in powers of the Deborah number, we develop a comprehensive theoretical analysis that yields analytical approximations for velocity fields, pressures, and forces acting on the sphere. Our framework aids in understanding temporal microstructural changes as the particle-wall gap evolves over time. In particular, we show that alterations in the polymer conformation tensor in response to geometric changes induce additional forces on the sphere. For cases with prescribed velocity, we present a theoretical approach for calculating resistive forces at any order in the Deborah number and utilize a reciprocal theorem to obtain higher-order corrections based on velocity fields in the previous orders. When the sphere translates with a constant velocity, the fluid viscoelasticity decreases the resistive force at the first order. However, at the second-order correction, the direction of the sphere's movement determines whether viscoelasticity increases or decreases the resistive force. For cases with prescribed force, we show that understanding the influence of viscoelasticity on the sphere's translational velocity necessitates a more intricate analysis even at low Deborah numbers. Specifically, we introduce an ansatz for constant force scenarios, and we derive solution forms for general prescribed forces using the method of multiple scales. We find that when a sphere undergoes sedimentation due to its own weight, the fluid viscoelasticity results in a slower settling process, reducing the leading-order sedimentation rate.","PeriodicalId":20160,"journal":{"name":"Physical Review Fluids","volume":"33 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210851","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

Tones and upstream-traveling waves in ideally expanded round impinging jets 理想膨胀圆形撞击射流中的音调和逆流波

IF 2.7 3区物理与天体物理

Physical Review Fluids Pub Date : 2024-08-21 DOI: 10.1103/physrevfluids.9.083904

Igor A. Maia, Maxime Fiore, Romain Gojon

{"title":"Tones and upstream-traveling waves in ideally expanded round impinging jets","authors":"Igor A. Maia, Maxime Fiore, Romain Gojon","doi":"10.1103/physrevfluids.9.083904","DOIUrl":"https://doi.org/10.1103/physrevfluids.9.083904","url":null,"abstract":"We study the generation of tones by ideally expanded round jets impinging on a flat plate. Data from large-eddy simulations performed for different nozzle-to-plate distances are explored, and we consider closure of the aeroacoustic feedback loop responsible for the tones by guided jet modes. Allowable frequency ranges for resonance, underpinned by the existence of modes with upstream-directed group velocities, are computed using two different models: a cylindrical vortex-sheet model, and a locally parallel stability model which considers a finite-thickness velocity profile. It is shown that inclusion of a finite-thickness velocity profile consistent with the mean flow in the vicinity of the plate improves the agreement between observed tones and model predictions. The frequencies of the largest tones found in the data are found to fall within, or very close to, the frequency limits of the finite-thickness model, correcting discrepancies observed with the vortex-sheet model. The same trend is observed in comparisons with experimental and numerical data gathered from the literature. Pressure eigenfunctions of the stability model are in good agreement with upstream-traveling disturbances educed from the data at the tone frequencies. This provides further evidence for the involvement of guided jet modes in the resonance mechanism.","PeriodicalId":20160,"journal":{"name":"Physical Review Fluids","volume":"12 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142227809","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

Single theoretical model for breakup of viscous thread with and without a fiber 有纤维和无纤维粘性线缆断裂的单一理论模型

IF 2.7 3区物理与天体物理

Physical Review Fluids Pub Date : 2024-08-20 DOI: 10.1103/physrevfluids.9.084005

Hyejoon Jun, Hyoungsoo Kim

{"title":"Single theoretical model for breakup of viscous thread with and without a fiber","authors":"Hyejoon Jun, Hyoungsoo Kim","doi":"10.1103/physrevfluids.9.084005","DOIUrl":"https://doi.org/10.1103/physrevfluids.9.084005","url":null,"abstract":"In this study, we introduce a comprehensive theoretical model for viscous liquid systems exhibiting Rayleigh-Plateau instability, accommodating cases both with and without a solid fiber. Employing the lubrication approach and implementing the hydrodynamic interaction at the solid-liquid interface, we formulate one-dimensional evolution equations for the breakup of viscous liquid threads and films on a fiber. Through several validations, we showed that our model exhibits a good agreement with experimental results in comparison to numerical simulations. Finally, our model, which incorporates the flow effect from the inner boundary condition by reconsidering the ansatz of a conventional long-wave approximation, provides a necessary condition for satellite droplet formation and determines the most unstable mode proportional to <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mrow><msup><mi>k</mi><mo>*</mo></msup></mrow><mn>2</mn></msup></math>, where <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mi>k</mi><mo>*</mo></msup></math> is the most unstable wavenumber. In addition, we observed that the volume of the satellite droplets exponentially decays depending on the wavenumber. Moreover, our single model integrates the findings of Goren's liquid film on a fiber and Rayleigh's viscous liquid thread, demonstrating its versatility and relevance to a wide range of systems.","PeriodicalId":20160,"journal":{"name":"Physical Review Fluids","volume":"49 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210866","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

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