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Study on rock strength weakening in multi-stage acid fracturing using continuous strength test Phys. fluids (IF 4.6) Pub Date : 2024-04-25 Qing Wang, Fujian Zhou, Hang Su, Siyu Zhang, Fuwei Yu, Rencheng Dong, Junjian Li, Zhangxin Chen
Multi-stage acid fracturing can boost productivity in low-permeability limestone reservoirs, with success hinging on differential etching and the strength of undissolved regions to keep fractures open. Traditional rock strength test methods have strong randomness and error. This study explores the influence of four acid systems (hydrochloric acid, single-phase retarded acid, gelled acid, and emulsified
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Hypersonic boundary layer over a flat plate with slip and shear nonequilibrium effects Phys. fluids (IF 4.6) Pub Date : 2024-04-25 Jihui Ou, Jie Chen
Near-space hypersonic vehicles could encounter significant rarefied nonequilibrium effects during the flight through atmosphere, which largely influence the gas-surface momentum and heat transfer. In this paper, hypersonic boundary layer over a flat plate with velocity slip, temperature jump, and shear nonequilibrium effects is theoretically considered. The slip boundary conditions and nonlinear transport
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Vortex bifurcation and air entrainment mitigation using multi-point intakes Phys. fluids (IF 4.6) Pub Date : 2024-04-25 Rahul Kumar Mondal, Lokesh Rohilla, Parmod Kumar
Air entrainment is a concern of paramount importance in the process industries, including nuclear power plant, hydraulic machines, water treatment plants, hydrocyclones, and power generation turbines. The ingression of the air into the equipment results in the reduction of the hydraulic efficiency. In the current paper, a combined experimental and numerical investigation has been performed using the
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Spiral eutectic growth dynamics facilitated by space Marangoni convection and liquid surface wave Phys. fluids (IF 4.6) Pub Date : 2024-04-25 Haipeng Wang, Dingnan Liu, Chenhui Zheng, Jiongfei Zhao, Jian Chang, Liang Hu, Hui Liao, Delu Geng, Wenjun Xie, Bingbo Wei
Eutectic alloys display excellent application performances since the essential function of coupled microstructures is quite different from that of single-phase and peritectic alloys. However, due to the strong natural convection within liquid alloys under normal gravity, the eutectic growth process on earth usually produces traditional rod-like or lamellar composite microstructures, which hinders the
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Fully passive model-based numerical analysis of the trailing-edge flexibility of hydrofoil on energy harvesting performance Phys. fluids (IF 4.6) Pub Date : 2024-04-25 Jianan Xu, Yuzhi Yao, Bailin Yi, Zenglei Zhang, Chaoyong Zong
The oscillating hydrofoil, a device used for collecting environmentally friendly tidal energy, is the focus of the study. The flexibility of the hydrofoil's trailing edge can impact its surface pressure distribution, lift, and moment characteristics. To improve the energy harvesting performance of oscillating hydrofoils, it is important to conduct thorough research on their energy harvesting mechanism
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Experiments investigation on atomization characteristics of a liquid jet in a supersonic combustor Phys. fluids (IF 4.6) Pub Date : 2024-04-25 Yaozhi Zhou, Chenyang Li, Zun Cai, Qinglian Li, Ziguang Li, Zihang Chen, Mingbo Sun
The atomization characteristics of a liquid jet in a supersonic combustor were studied experimentally for the first time. A phase doppler anemometry (PDA) system was utilized for the measurement of droplets properties along the cross-sectional area of spray plumes inside the cavity. The results were obtained under the inflow conditions of Ma = 2.0 supersonic crossflow with a stagnation pressure of
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A comprehensive deep learning geometric shape optimization framework with field prediction surrogate and reinforcement learning Phys. fluids (IF 4.6) Pub Date : 2024-04-25 Hao Ma, Jianing Liu, Mai Ye, Oskar J. Haidn
The optimization of aerodynamic components' geometric shapes demands a novel technical approach for adaptive and efficient exploration and decision-making within the design space. In this study, we introduce an innovative shape optimization framework that leverages deep reinforcement learning with neural network surrogate models. The field prediction surrogate, realized by two distinct U-net architectures
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Dynamics of multi-mode nonlinear internal waves in fluids of great depth Phys. fluids (IF 4.6) Pub Date : 2024-04-25 Zi'an Wang, Ganghua Hu, Zhan Wang
This paper is mainly concerned with the dynamics of strongly nonlinear internal waves in two-dimensional fluids of great depth. A fully nonlinear model for a three-layer fluid of great depth containing topography, a Miyata–Choi–Camassa (MCC)-type system, is developed based on the generalization of the Ablowitz–Fokas–Musslimani global-relation formulation for free-surface water waves. Mode-1 internal
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Numerical modeling of self-aerated flows: Turbulence modeling and the onset of air entrainment Phys. fluids (IF 4.6) Pub Date : 2024-04-25 F. Zabaleta, F. A. Bombardelli, S. Márquez Damián
Numerical modeling of self-aerated flows is essential for understanding water systems and designing hydraulic structures. This work discusses and extends a theoretical/numerical model to represent air entrainment in self-aerated flows, which includes a criterion to define the occurrence of air entrainment, based on a balance between disturbing and stabilizing energies. The impact of the turbulence
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Molding the acoustic cavity–analyzing the influence of toroidal vortex development on acoustic multi-bubble macrostructures under different ultrasonic horn tip diameters Phys. fluids (IF 4.6) Pub Date : 2024-04-25 Basel Al Bishtawi, Khameel Bayo Mustapha, Gianfranco Scribano
The acoustic cavity structure typically experiences a sequence of transfigurations during its sinusoidal growth–collapse cycle. However, upon examining the cavity structure in aqueous bodies, it appears that the growth structure attained falls between two geometrical structures, namely, mushroom-like structure (MBS) and cone-like bubble structure (CBS), based on the actuated ultrasonic horn tip diameter
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Direct numerical simulations of high-enthalpy supersonic turbulent channel flows including finite-rate reactions Phys. fluids (IF 4.6) Pub Date : 2024-04-25 Xiao-Ping Chen, Yu-Ting Yang, Shuo Zhao
Direct numerical simulations of temporally evolving high-enthalpy supersonic turbulent channel flows are conducted at a Mach number of 3.0 and Reynolds number of 4880 under isothermal wall conditions. Air is assumed to behave as a five-species mixture, and chemical non-equilibrium and equilibrium assumptions are adopted to investigate the influence of finite-rate reactions on the turbulent statistics
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Breathing in danger: Mapping microplastic migration in the human respiratory system Phys. fluids (IF 4.6) Pub Date : 2024-04-25 Hafiz Hamza Riaz, Abdul Haseeb Lodhi, Adnan Munir, Ming Zhao, Umar Farooq, M. Nafees Mumtaz Qadri, Mohammad S. Islam
The abundance of air pollutants over the last few years, including the concentration of microplastics, has become an alarming concern across the world. Initially discovered in marine life, these toxic and inflammatory particles have recently been found in human lung tissues. When inhaled, these harmful particles settle down in the lung airways and, over time, lead to respiratory failures. A recent
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Drag reduction of the turbulent boundary layer over divergent sawtooth riblets surface with a superhydrophobic coat Phys. fluids (IF 4.6) Pub Date : 2024-04-25 Jinge Hu, Zhaohui Yao
Energy conservation and environmental protection have become pivotal components of the green economy. In recent years, underwater drag reduction technology has garnered significant interest. This study discusses a novel composite surface that combines divergent riblets with a superhydrophobic coating (D-rib&SHS) to enhance the drag reduction rate. Alongside this new surface, a riblet surface with a
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Wing design optimization and stall analysis with Co-flow Jet active control Phys. fluids (IF 4.6) Pub Date : 2024-04-25 Hao Jiang, Weigang Yao, Boda Zheng, Min Xu
Coupled with Co-flow Jet (CFJ) technology, the Non-dominated Sorting Genetic Algorithm II was utilized for the multi-objective combination optimization of an optimized Co-flow Jet wing, based on National Advisory Committee for Aeronautics (NACA) 6421. A high-precision numerical simulation using the delayed detached eddy simulation model was performed on the optimized wing to investigate the three-dimensional
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An analytical study for predicting incipient motion velocity of sediments in ecological open channel flows Phys. fluids (IF 4.6) Pub Date : 2024-04-25 Jiao Zhang, Zhangyi Mi, Wen Wang, Zhanbin Li, Peng Li, Jiakuan Xu, Jing Li, Huilin Wang, Zi Wu
Sediment movements on the riverbeds are crucial in fluvial processes. Therefore, studying incipient sediment motion is valuable for predicting changes in sediment behavior. In this study, the influence of aquatic vegetation is introduced into the momentum balance equation under the condition of a bare bed. The presented model for incipient sediment motion in open channels covered by vegetation is derived
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Influence of inflow conditions on simplified heavy vehicle wake Phys. fluids (IF 4.6) Pub Date : 2024-04-24 Shuai Han, Fan Wang, Jie Zhang
In the current study, the impact of various inflow conditions, including turbulent wind profiles and turbulent intensity, on the wake flow topology of a simplified ground transportation system (GTS) model was investigated using the improved delayed detached eddy simulation. The reliability and accuracy of the numerical method adopted in this paper were verified against the results comprising the aerodynamic
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Numerical prediction and optimization of aerodynamic noise of straw crushers by considering the straw-crushing process Phys. fluids (IF 4.6) Pub Date : 2024-04-24 Yu Zhao, Zhiping Zhai, Bo Gao, Yuezheng Lan
Straw crops are struck and broken into soft filaments by the high-speed rotating hammers of straw crushers, which disturb the internal airflow field and generate much noise during the operation of straw crushers. To accurately estimate and reduce the aerodynamic noise of straw crushers at the design stage, in this study, first, the coupling method of the discrete element method, bonded-particle model
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Numerical investigation of turbulence generation using Zakharov-like model equation Phys. fluids (IF 4.6) Pub Date : 2024-04-24 Praveen Kumar, R. Uma, R. P. Sharma
This study investigates the turbulence generation behavior with a Zakharov-like (ZL) equation in a fluid system. The model equation is derived using conservation equations (mass and momentum conservation), and the source of nonlinearity is the high amplitude of the acoustic wave. The Zakharov-like equation has been derived and then solved numerically, then turned into a modified nonlinear Schrödinger
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Flow of a colloidal solution in an orthogonal rheometer Phys. fluids (IF 4.6) Pub Date : 2024-04-24 Krishna Kaushik Yanamundra, Chandler C. Benjamin, Kumbakonam Ramamani Rajagopal
The flow of a colloidal solution between two parallel disks rotating with the same angular velocity about two non-coincident axes was studied. The problem has been approached from two perspectives, the first wherein the stress is expressed in terms of a power-law of kinematical quantities, and the second wherein we consider a non-standard model where the symmetric part of the velocity gradient is given
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Effect of fluid–structure interaction on the oblique water entry of the projectile under the influence of floating ice structure Phys. fluids (IF 4.6) Pub Date : 2024-04-24 Xinyu Hu, Yingjie Wei, Cong Wang
The water entry of a projectile constrained by polar floating ice presents a unique cross-media challenge. This paper investigates the dynamics of oblique water entry for a projectile influenced by floating ice using the fluid–structure interaction (FSI) method. The validity of the numerical method has been confirmed through experimental validation. The water entry process of a projectile from the
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Three-dimensional particle image velocimetry measurement through three-dimensional U-Net neural network Phys. fluids (IF 4.6) Pub Date : 2024-04-24 Lixia Cao, Md. Moinul Hossain, Jian Li, Chuanlong Xu
This paper proposes a light field (LF) three-dimensional (3D) particle image velocimetry (PIV) method based on a digital refocused algorithm and 3D U-Net neural network for 3D three-component (3D-3C) velocity measurement. A digital refocused algorithm is used to generate a stack of LF-refocused images of tracer particles for establishing the 3D U-Net. The 3D U-Net is then used for the 3D particle field
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Sedimentation of a spheroidal particle in an elastoviscoplastic fluid Phys. fluids (IF 4.6) Pub Date : 2024-04-24 Alie Abbasi Yazdi, Gaetano D'Avino
The sedimentation dynamics of a prolate spheroidal particle in an unbounded elastoviscoplastic (EVP) fluid is studied by direct finite element simulations under inertialess flow conditions. The Saramito–Giesekus constitutive equation is employed to model the suspending liquid. The arbitrary Lagrangian–Eulerian formulation is used to handle the particle motion. The sedimentation, lift, and angular velocities
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Effects of liquid water injection on flame surface topology and propagation characteristics in spray flames: A direct numerical simulation analysis Phys. fluids (IF 4.6) Pub Date : 2024-04-24 R. Concetti, J. Hasslberger, N. Chakraborty, M. Klein
The effects of water injection on flame surface topology and local flame propagation characteristics have been analyzed for statistically planar turbulent n-heptane spray flames with an overall (i.e., liquid + gaseous) equivalence ratio of unity using carrier-phase direct numerical simulations. Most fuel droplets have been found to evaporate as they approach the flame even though some droplets can
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Numerical simulation of the interaction between a planar shock wave and a backward-facing triangular bubble containing gases with different Atwood numbers Phys. fluids (IF 4.6) Pub Date : 2024-04-24 Murugan Thangadurai, Abhishek Kundu, Gautam Biswas
The interaction between a shock wave and an interface delineating two gases engenders intricate flow physics, with particular attention drawn to the hydrodynamic instability due to its practical significance. Previous studies have primarily focused on elucidating different wave patterns and instabilities evolution at the interface during the initial phase of shock interaction with cylindrical or spherical
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Fluid dynamics of a flapping wing interacting with the boundary layer at a flat wall Phys. fluids (IF 4.6) Pub Date : 2024-04-24 Chihao Lin, Pan Jia, Chao Wang, Zheng Zhong
In this paper, we consider the fluid dynamics of a flapping wing interacting with a boundary layer developed at a no-slip flat wall. Direct numerical simulations are carried out via implementing the non-iterative immersed boundary-lattice Boltzmann method, over a Reynolds number range of 10≤Re≤1000, for a fixed Strouhal number of St = 0.3 and for a given symmetric plunging and pitching flapping motion
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Bounce and contact mode regimes for drop impact on smooth surfaces: The influence of gas kinetics and electrostatics Phys. fluids (IF 4.6) Pub Date : 2024-04-24 Hanyi Liu, Jun Zhang
When liquid drops impact on solid surfaces, an air layer forms in between the drop and the surface, acting as a cushion to mitigate the impact. In this work, we focus on delineating the bounce and contact mode regimes of impacting drops on smooth surfaces, specifically discerning whether drops rebound from the air layer or make contact with the solid surfaces, and pinpointing the precise contact modes
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Data-driven modal analysis of turbulent momentum exchange and heat transfer in composite porous fluid systems Phys. fluids (IF 4.6) Pub Date : 2024-04-24 Mohammad Jadidi, Yasser Mahmoudi
This paper investigates the dynamics governing turbulent momentum exchange and heat transfer between pore flow within porous media and the turbulent flow passing over it. Employing high-fidelity pore-scale large eddy simulation, our investigation explores the fundamental mechanisms driving these phenomena. Modal analysis based on snapshot proper orthogonal decomposition (POD) is employed to quantify
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Impacting dynamics of nanodroplets on superhydrophobic surfaces decorated by a ridge Phys. fluids (IF 4.6) Pub Date : 2024-04-24 Zhi-Hui Cai, Yi-Feng Wang, Ben-Xi Zhang, Qi-Hui Jia, Yan-Ru Yang, Shao-Fei Zheng, Duu-Jong Lee, Xiao-Dong Wang
Reducing the contact time of impacting nanodroplets is of fundamental interest and importance due to its promising potential in various engineering applications, such as self-cleaning and anti-icing. In this work, nanodroplets impacting superhydrophobic surfaces decorated by a rectangular ridge are studied over a wide range of Weber number (We) and different sizes of the ridge via molecular dynamics
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An improved wall boiling model for numerical simulation of subcooled flow boiling on a new hybrid micro/nanostructured surface Phys. fluids (IF 4.6) Pub Date : 2024-04-24 Yitian Yu, Shenghong Huang, Zhanru Zhou, Guangxi Li, Xiande Fang
Previous studies have demonstrated that micro/nanostructured surfaces have great potential for heat transfer enhancement. However, simulating subcooled flow boiling on such surfaces is difficult owing to the lack of proper bubble characteristic parameter models, because most models used in flow boiling simulations were developed based on smooth surface conditions, which may limit their applications
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Aeroacoustic investigation of a ducted wind turbine employing bio-inspired airfoil profiles Phys. fluids (IF 4.6) Pub Date : 2024-04-24 Mostafa Mozafari, Mahyar Sadeghimalekabadi, Amirhossein Fardi, Christoph Bruecker, Mehran Masdari
Ducted wind turbines for residential purposes are characterized by a lower diameter with respect to conventional wind turbines for on-shore applications. The noise generated by the rotor plays a significant role in the overall aerodynamic noise. By making modifications to the blade sections of the wind turbine, we can alter the contributions of aeroacoustic noise sources. This study introduces innovative
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Numerical study of free stream turbulence effects on dynamic stall of pitching tubercled wings Phys. fluids (IF 4.6) Pub Date : 2024-04-24 Ming Zhao, Weibin Chen, Jiahuan Chen, Lianchao Xu, Xiaojian Li, Zhengxian Liu
The feasibility of a tubercled leading-edge in dynamic stall control has been validated, and the impacts of an upstream cylinder wake have already been discussed in the previous research. However, the influences of wake coherent characteristics on the dynamic stall process are inevitable. To this end, the synthetic turbulence method was adopted in the present study to generate incoming turbulence.
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High-speed photography and particle image velocimetry of cavitation in a Venturi tube Phys. fluids (IF 4.6) Pub Date : 2024-04-24 Zhen Wang, Qin Zhao, Zeyuan Yang, Ruifeng Liang, Zhenggui Li
This article details the construction of an experimental visualization platform for observing cavitation. The platform uses high-speed photography and particle image velocimetry (PIV) techniques to conduct experimental research into the flow pattern and vortex field of cavitation in Venturi tubes. Dynamic mode decomposition is employed to extract the energy distribution characteristics of the cavitation
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Investigation on the effect of particle parameters on the erosion and erosion prediction model of the Pelton turbine Phys. fluids (IF 4.6) Pub Date : 2024-04-24 Lei Han, Chuanliang Guo, Yujie Gao, Deyou Li, Hongjie Wang, Yongxin Liu, Alfredo Iranzo, Daqing Qin
The Pelton turbine will play a massive role in China's water conservancy and power generation development process. In practical engineering applications, sediment will erode the components of the Pelton turbine when they come into contact, threatening the safe and stable operation of the unit. Therefore, based on the Eulerian–Lagrangian method, this study analyzes the effects of particle size, concentration
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Thermocapillary motion of a solid cylinder near a liquid–gas interface: Janus geometry Phys. fluids (IF 4.6) Pub Date : 2024-04-24 A. Arslanova, G. Natale, S. Fransen, N. Reddy, C. Clasen, J. Fransaer
In this work, an analytical model is developed for the thermocapillary propulsion of a solid cylinder near a convective liquid–gas interface. Thermocapillarity originates from the temperature-induced surface tension gradients at the liquid–gas interface when the surface temperature of a cylinder residing near the interface differs from the liquid phase. In this work, we consider Janus cylinders with
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Investigation of the spreading of a liquid metal droplet under a vertical magnetic field Phys. fluids (IF 4.6) Pub Date : 2024-04-24 Jiandong Zhou, Zixin Cheng, Yuhao Tang, Juancheng Yang
In the liquid metal divertor of a magnetic confinement fusion device, the spreading characteristics of the liquid metal are crucial for ensuring the stable operation of the divertor. This study has experimentally investigated the spreading characteristics of a GaInSn alloy droplet on a solid substrate under a strong vertical magnetic field, with the magnetic field intensity ranging from 0 to 2.5 T
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Mass transfer of solute in an oscillating flow in a two-dimensional channel Phys. fluids (IF 4.6) Pub Date : 2024-04-24 Anastasya Bushueva, Denis Polezhaev
The effective diffusion of a solute in a rectangular two-dimensional channel is experimentally studied. We experimentally examine the effective diffusion of Rhodamine B dissolved in water oscillating in a rectangular Hele–Shaw cell. The concentration of Rhodamine B in water is measured by the intensity of its fluorescence emission. In particular, we consider two problems: (i) effective diffusion of
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Numerical study on the effects of fracture on density-driven flows in CO2 sequestration Phys. fluids (IF 4.6) Pub Date : 2024-04-23 Peiyao Liu, Long Ju, Jun Pu, Zhaoli Guo
In this study, CO2 transport in density-driven flows within an ideal model of a fractured porous medium, which contains a single or two intersecting fractures, is investigated numerically. The study employs a multi-scale modeling in which the flow in the matrix is modeled by Darcy's law, while the flow in the fracture is modeled by the Navier–Stokes equations. Our study shows that a horizontal fracture
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An analytical model for permeability of fractal tree-like branched networks composed of converging–diverging capillaries Phys. fluids (IF 4.6) Pub Date : 2024-04-23 Biliang Tu, Boqi Xiao, Yidan Zhang, Gongbo Long
Seepage processes in tree-fractal networks have attracted extensive research, but the results of most of these studies presuppose a constant pore cross section. This research investigates fluid flow in a fractal tree-like branching network composed of five different types of circular cross section pipes and establishes the effective permeability of the network. Furthermore, the effective permeability
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Construction of the absorbing boundary condition for the flow of Oldroyd-B fluid over a semi-infinite plate with magnetic effect Phys. fluids (IF 4.6) Pub Date : 2024-04-23 Lin Liu, Sen Zhang, Jihong Wang, Libo Feng, Chiyu Xie
As a kind of non-Newtonian fluid, the Oldroyd-B fluid has widespread applications. To study the flow characteristics deeply is of great significance. In this paper, we consider a simple model of the Oldroyd-B fluid flow over a semi-infinite plate in a magnetic field. The governing equation is formulated, and the numerical solutions are obtained using the finite difference method. To deal with the semi-infinite
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Research of bubble motion and correction of drag coefficient in viscous oil at low Reynolds number Phys. fluids (IF 4.6) Pub Date : 2024-04-23 Shiqi Liu, Qingdong Yan, Meng Guo, Cheng Liu, Haoyuan Wang, Wei Wei
As the core fundamental components in the field of fluid transmission and control, viscous oil fluid components determine the technological level of fluid machinery and high-end equipment. However, bubbles as effective cavitation nuclei widely exist in the interior of viscous oil fluid components, directly affecting their performance and technological development. In order to reveal the bubble motion
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Optimization of stepped revetment configuration on minimizing wave run-up and overtopping Phys. fluids (IF 4.6) Pub Date : 2024-04-23 Hany Qoshirotur Rif'atin, Ikha Magdalena, Dara Dewata, Cherdvong Saengsupavanich, Sarinya Sanitwong-na-Ayutthaya
A stepped revetment has proven to be able to attenuate wave run-up height and wave overtopping discharge more effectively than a dike or a smooth-slope revetment does. However, the investigation into the optimal design of a stepped revetment, tailored to different wave and coastal conditions, is notably lacking. This paper introduces a computational model developed from the non-linear shallow water
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Exploring the excess of cloud condensation nuclei and rain suppression using a minimal three-dimensional Boussinesq model with bulk cloud microphysics Phys. fluids (IF 4.6) Pub Date : 2024-04-23 Olmo Guerrero Medina, Gerardo Hernández-Dueñas
Over the years, there have been discussions about the possibility of air pollution affecting the process of rain formation. In this study, we have developed a simplified model that represents the atmospheric dynamics and cloud microphysics to explore the impact of pollution on rain formation. We used an existing three-dimensional minimal model consisting of five equations, for which we added a simple
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An improved immersed boundary method with local flow pattern reconstruction and its validation Phys. fluids (IF 4.6) Pub Date : 2024-04-23 Wang Yudong, Wang Fang, Zhou Jiawei, Jin Jie
This study introduces an immersed boundary (IB) method based on coefficient array transformations of discrete equations for local cells and local flow pattern reconstruction, for the simulation of turbulent flow and combustion chemistry inside combustors with complex structure. This IB method is combined with a geometric scanning algorithm that traverses each fluid grid point in the vicinity of the
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Rayleigh–Plesset-based Eulerian mixture model for cavitating flows Phys. fluids (IF 4.6) Pub Date : 2024-04-23 M. Cianferra, V. Armenio
The homogeneous mixture model (HMM) is widely in use for simulation of cavitating flows. The mass transfer is typically ruled by simplified models whose efficiency is strictly dependent on the empirical choice of vaporization/condensation constants. In the present paper, we formulate a physically based mass-transfer model relying on the solution of the complete Rayleigh–Plesset (RP) equation. The latter
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Insilco study of luminal transport of bile salts from the duodenum to the gastric mucosa: Role of small intestinal peristalsis Phys. fluids (IF 4.6) Pub Date : 2024-04-23 Ravi Kant Avvari, Dharmendra Tripathi
Biliary reflux plays a key role in the progression of gastric carcinoma over the long term. The reflux of alkaline duodenal contents (Duodenogastric Reflux) is presumed to be mediated by changes in the gastroduodenal motility, with no clear insights into the mechanisms. Considering mechanism comes under the perspective of fluid transport, a mathematical model is formulated for investigating the transport
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Numerical simulation and experimental investigation of pressure pulsation-induced nonlinear characteristics in marine twin-screw pumps under various clearance between rotor and stator Phys. fluids (IF 4.6) Pub Date : 2024-04-23 Jiantao Shen, Li Cheng, Weixing Yang, Weifeng Pan, Weixuan Jiao, Bowen Zhang
The twin-screw pump (TSP) is widely used in naval engineering for seawater transportation and treatment. However, the diverse composition of seawater, often containing impurities, poses a risk of screw corrosion and jamming of clearances. Detecting the compact internal structure's clearance between rotor and stator (GAPR) proves challenging. To address these challenges, a novel approach combining chaos
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Analysis of the directional and spectral distributions of kinetic energy in aortic blood flow Phys. fluids (IF 4.6) Pub Date : 2024-04-23 David Büchner, Emily Louise Manchester, Xiao Yun Xu
It has been recognized that blood flow in large vessels, such as the aorta, may undergo a transition to turbulent flow in the presence of cardiovascular disorders, while flow in the healthy aorta is perceived to be laminar under normal physiological conditions. However, this perception has been challenged by several studies, highlighting the need to consider more fundamental flow characterizations
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Ice accretion simulation incorporating roughness effects and separation correction through a transition model Phys. fluids (IF 4.6) Pub Date : 2024-04-23 Jiawei Chen, Yufei Zhang, Song Fu
In the simulations of ice accretion, accurately modeling the impact of surface roughness and calculating the separated flow are crucial aspects. A modified laminar–turbulent transition model that incorporates both separation and roughness-induced transition correction is employed for icing simulations. An iced airfoil was selected to validate the modified model's predictive capability for large separation
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The role of permeability in lid-driven cavity flow containing a cluster of hot solids Phys. fluids (IF 4.6) Pub Date : 2024-04-23 Yunxin Zhang, Chenggong Li, Mao Ye
The flow behavior of particle clusters with thermal convection in confined fluid flow has garnered considerable attention. One of the remaining challenges is to understand the role of a porous structure of particle clusters in the confined thermal fluid flow. In present work, a numerical study based on a double distribution function lattice Boltzmann model has been conducted to unveil the two-sided
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Phenomenon of self-oscillation in bubble dynamics: Bouncing acoustic bubbles Phys. fluids (IF 4.6) Pub Date : 2024-04-23 Gabriel Regnault, Alexander A. Doinikov, Gabrielle Laloy-Borgna, Cyril Mauger, Philippe Blanc-Benon, Stefan Catheline, Claude Inserra
Self-oscillations underlie many natural phenomena, such as heartbeat, ocean waves, and the pulsation of variable stars. From pendulum clocks to the behavior of animal groups, self-oscillation is one of the keys to the understanding of synchronization phenomena and hence to the collective behavior of interacting systems. In this study, we consider two closely spaced bubbles pulsating in the kHz range
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Research on pressure pulsation characteristics of a pump-turbine in pump mode with rotating stall: Focus on the broadband frequency Phys. fluids (IF 4.6) Pub Date : 2024-04-23 Yongshun Zeng, Zhaohui Qian, Weixiang Ye, Chen Geng, Xianwu Luo
To investigate the adverse effects of rotating stalls on the pressure pulsation characteristics of a pump-turbine in pump mode, an unsteady numerical simulation was carried out by applying the partially averaged Navier–Stokes turbulence model. The numerical methods were carefully verified, and the onset flow rate of the hump at the performance curve and heads were in good agreement with the experimental
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Droplet impact simulation with Cahn–Hilliard phase field method coupling Navier-slip boundary and dynamic contact angle model Phys. fluids (IF 4.6) Pub Date : 2024-04-23 Zunru Fu, Haichuan Jin, Guice Yao, Dongsheng Wen
As a highly promising interface capture tool, the phase field method (PFM) has gained fast development in the past 20 years or so including in the simulation of droplet impact. The mobility tuning parameter χ of PFM, however, is hard to determine since it ambiguously reflects the relative strength between advection and diffuse effects that are difficult to quantify. This problem becomes even more complex
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Secondary flows in the actuator-disk simulation of wind-turbine wakes Phys. fluids (IF 4.6) Pub Date : 2024-04-23 Navid Zehtabiyan-Rezaie, Ali Amarloo, Mahdi Abkar
This study explores the generation of secondary flows of Prandtl's second kind in the actuator-disk simulation of wind-turbine wakes. Leveraging large-eddy simulation data and conducting an analysis of the mean streamwise vorticity budget, we uncover the physical mechanisms contributing to this phenomenon. Our investigations attribute the emergence of such flows to the spatial gradients of the Reynolds
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Flocculation rate of locally densely distributed cohesive particles in Taylor–Green vortex flow Phys. fluids (IF 4.6) Pub Date : 2024-04-23 Kunpeng Zhao, Shuaiqi Zhao, Han Huang, Rui Zhang, Eckart Meiburg, Bofeng Bai
We employ the three-way coupled numerical simulations to investigate the flocculation of primary cohesive particles which are locally densely distributed in the Taylor–Green cellular vortex flow. The hydrodynamic and inertial forces as well as the direct contact, lubrication, and cohesion forces between particles during the growth, deformation, and breakup of flocs are captured in detail. The flocculation
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Heat transfer analysis for magnetohydrodynamic peristalsis of Reiner–Philippoff fluid: Application of an artificial neural network Phys. fluids (IF 4.6) Pub Date : 2024-04-22 J. Iqbal, F. M. Abbasi, I. Ali
Present communication explores a novel application of the computational intelligence technique, namely, the Levenberg–Marquardt scheme under a Backpropagated Neural Network (LM-BNN) to solve the mathematical model for the magnetohydrodynamic peristaltic transport of Reiner–Philippoff (R–Ph) pseudoplastic fluid considering the influences of Ohmic heating, mixed convection, and viscous dissipation through
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A deep-learning-based compact method for accelerating the electrowetting lattice Boltzmann simulations Phys. fluids (IF 4.6) Pub Date : 2024-04-22 Zijian Zhuang, Qin Xu, Hanxian Zeng, Yongcai Pan, Binghai Wen
Research on the electrowetting of micro- and nanoscale droplets is essential for microfluidics and nanomaterials applications. A lattice-Boltzmann-electrostatics (LBES) method is an effective and accurate method for simulating this process. However, the electric potential field in each time step requires numerous iterative calculations to converge. Therefore, there is a trade-off dilemma between using
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An accurate and efficient deep learning model for spatio-temporal prediction of interfacial flows Phys. fluids (IF 4.6) Pub Date : 2024-04-22 Yangyu Deng, Di Zhang, Ze Cao, Yakun Liu
Aiming at fast and accurate spatiotemporal prediction of interfacial flow fields, a novel deep learning model combining Convolutional AutoEncoder (CAE) and long short-term memory with spatial and temporal attention (LSTM-STA) is proposed and named as CAE-LSTM-STA (hybrid model of CAE and LSTM-STA) in this article. To enable a fast calculation process, CAE is first utilized to compress the high-dimensional
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Design and thermodynamic analysis to avoid preheating in gas grid pressure reduction stations Phys. fluids (IF 4.6) Pub Date : 2024-04-22 Wajdi Rajhi, Ali Basem, Khitam Salim Shaker, Kamal Sharma, Dheyaa J. Jasim, Walid Aich, Badreddine Ayadi, Reza Alayi
Paying close attention to the environmental risks associated with traditional forms of energy, particularly the serious issue of global warming caused by the release and concentration of greenhouse gases, has become a paramount concern. This growing awareness has prompted governments worldwide to prioritize the benefits of alternative energy sources and develop comprehensive plans accordingly. Moreover
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Air-lift characteristics of rock core mass in gas–liquid–solid mixed flow Phys. fluids (IF 4.6) Pub Date : 2024-04-22 Ziyang Hou, Yongsheng Liu, Gansheng Yang, Jianxin Xia
The air-lift reverse circulation drilling method enables efficient and continuous core extraction. However, the flow characteristics of gas–liquid–solid mixtures during core mass transport are complex, and developing a model to predict performance remains challenging. The flow characteristics of gas–liquid–solid mixtures inside the drill pipe are numerically analyzed by calculating the mixing transport
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Vortex shedding from a square cylinder interacting with an undular bore wave train Phys. fluids (IF 4.6) Pub Date : 2024-04-22 C. Barraud, R. H. Hernández
In this work, we studied the wave-induced vortex generation and shedding from a semi-submerged vertical square cylinder interacting with an upcoming undular bore wave train under a shallow water configuration. This unsteady and rapid process was investigated by means of numerical and experimental approaches. A numerical simulation, solving the full turbulent viscous Navier–Stokes equations, was carried