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Fractal study of electrical conductivity and streaming potential in rough fractured porous media Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2024-02-27 Shanshan Yang, Kaicong Xu, Sheng Zheng
Research has demonstrated the significant influence of surface roughness on electrical conductivity and streaming potential. This article presents a model for the flow potential in a porous medium with rough fractures, based on fractal theory and representative elementary volume theory. Expressions for the model’s permeability, conductivity, and coupling coefficient between flow and potential are derived
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Mean flow induced by longitudinal libration of a fluid-filled rotating container bounded by two conical surfaces Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2024-02-23 M.V. Kurgansky
The problem of determining a mean flow induced by longitudinal libration of a rapidly rotating fluid-filled container bounded by the surfaces of two oppositely oriented right circular cones is considered. It is shown that the problem is reduced, through introducing a cosine of the angle between the normal to the conical surfaces and the axis of rotation, to the problem of determining a mean flow induced
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Spatial estimation of unidirectional wave evolution based on ensemble data assimilation Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2024-02-23 Zitan Zhang, Tianning Tang, Ye Li
With the limitation of the high sensitivity of nonlinear models to initial conditions, the accurate estimation of wave spatial evolution is difficult to perform at a long distance. At this stage, a helpful approach is to improve the accuracy and robustness of the model through data assimilation technique. A robust data assimilation framework is developed by coupling ensemble Kalman filtering (EnKF)
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Influence of passive deformation in the lift coefficient of a NACA0012 wing model Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2024-02-17 E. Duran, M. Lorite-Díez, N. Konovalov-Shishov, P. Gutierrez-Castillo, C. del Pino
The extensive use of lightweight materials in aerial vehicle wings involves structural flexibility phenomena that generate non-negligible deformation effects. This influence is not restricted to big aircraft but also plays a role in smaller aeroplanes and Unmanned Aerial Vehicles (UAVs). Here, we conduct wind tunnel experiments to analyze the effect of passive deformation on the wing model lift slopes
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Optimization of semi-active hydrofoil propulsion performance based on CFD Taguchi method and neural network Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2024-02-16 Zhenyu Song, Jianyang Zhu, Chao Wang
In order to improve the propulsive performance of the existing pure heaving motion hydrofoil, the effect of varying stiffness ratio , damping ratio and inertia ratio on the propulsive efficiency of the semi-active NACA 0012 hydrofoil is systematically investigated by using the combination of CFD, Taguchi method and neural network. The results show that the passive pitching motion can significantly
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Flow Analysis for Lateral Synthetic Jets to Remove Contaminants from the Outer Surface of an Automobile Camera Module Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2024-02-13 Jihyeon Park, Jaeik Ko, Ji Hoon Song, Minsuk Choi
A test facility was constructed to investigate the flow characteristics of lateral synthetic jets generated by an actuator composed of a cavity, an orifice and a vibrating piezoelectric disc. Subsequently, 3D unsteady numerical simulations were conducted to analyze the formation of the synthetic jets and their dependence on the height of the orifice exit from the outer surface of the cavity. The time-averaged
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Modal analysis for incompressible fluid flow Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2024-02-12 Satoshi Ishikawa, Takaaki Yamaoka, Shinya Kijimoto
This paper presents a numerical method for incompressible fluid flow. A difficulty in analyzing incompressible fluid flow is that the continuity equation has no time evolution term. In the marker and cell (MAC) method, Poisson’s equation is solved iteratively, which takes most of the computation time, and in the artificial compressibility method (ACM), pseudo-time iteration is necessary to solve for
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The dynamics of the droplet impact and rebound: A lattice Boltzmann study Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2024-02-10 Yawen Deng, Xi Liu, Chengjie Zhan, Zhenhua Chai, Baochang Shi
In this work, the droplet impact and rebound behaviors on a flat substrate are comprehensively investigated by using the consistent and conservative phase-field based lattice Boltzmann method, which is robust for the multiphase flow problems with the large density ratios and long-time dynamics. The dynamic behavior of the droplet considered here is governed by five key factors: the contact angle, droplet
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Influence of the turbulent closure for the prediction of the linear response of a flow bounded by a corrugated wall Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2024-02-09 Maxime Stuck, François Chedevergne, Marina Olazabal-Loumé, Jacques Couzi
We investigate the influence of the turbulent closure in Reynolds-Averaged Navier–Stokes (RANS) simulations for the prediction of the linear response of a turbulent boundary layer developping over a small-amplitude corrugated wall. Experimental studies by Hanratty and co-workers (Zilker et al. 1977; Abrams and Hanratty, 1985; Frederick and Hanratty, 1988) show a phase shift between the wall shear stress
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Vorticity alignment with Lyapunov vectors and rate-of-strain eigenvectors Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2024-02-08 A. Encinas-Bartos, G. Haller
We derive asymptotic estimates for the projection of the vorticity onto principal directions of material stretching in 3D flows. In flows with pointwise bounded vorticity, these estimates predict vorticity alignment with Lyapunov vectors along trajectories with positive Lyapunov exponents. Specifically, we find that in inviscid flows with conservative body forces, the vorticity exactly aligns with
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Migration of a multi-core compound droplet in a ratchet microchannel Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2024-02-03 Nang X. Ho, Hung V. Vu, Truong V. Vu
With the unique structure of multi-core compound droplets, they are increasingly used in various industrial production fields, material fabrication, biological sciences, medicine, and other numerous promising large-scale applications. This study focuses on using a front tracking method to study the dynamics of a multi-core compound droplet as it moves within a ratchet microchannel. The dynamics of
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Transitions in a Poiseuille-Rayleigh-Bénard flow in a vertical slender long duct Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2024-02-01 Raúl Rechtman, Alejandra García-Morales, Guadalupe Huelsz
The flow of air inside a vertical slender long duct with a temperature difference between the horizontal walls characterized by the Rayleigh number and a pressure gradient in the horizontal direction characterized by the Reynolds number is studied using the lattice Boltzmann method. In this case, the longitudinal rolls found in ducts with a width larger than the height cannot develop and the flow remains
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CFD modelling of velocity fields around a fume cupboard: Evaluating static and dynamic meshes with experimental measurements Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2024-01-31 A. Manning, L. Qian, R. Erfani
This paper presents a comparison of experimental and numerical modelling results of the velocity field around a fume cupboard with a static and a dynamic mesh. During fume cupboard testing, components are required to move which mimic typical operating conditions, the amount of tracer gas released is then measured. This tracer gas is harmful to the environment and so an alternative is required. Advanced
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Study on mechanism of VIV causing limited amplitude vibration through LES for a 4:1 rectangular cylinder Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2024-01-22 Yuanyan Tang, Yi Hui, Ke Li
Vortex-induced vibration (VIV) is characterized as a phenomenon of limited amplitude vibration. Understanding the basic nature and underlying mechanism of VIV is necessary for predicting the vibration amplitude. In this study, using Large Eddy Simulation (LES) of forced vibration, a detailed investigation of the flow pattern and wind load during VIV of a 4:1 rectangular cylinder is conducted. The results
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An in vitro experimental investigation of oscillatory flow in the cerebral aqueduct Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2024-01-23 S. Sincomb, F. Moral-Pulido, O. Campos, C. Martínez-Bazán, V. Haughton, A.L. Sánchez
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Investigations on bifurcation behavior of wind turbine airfoil response at a high angle of attack Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2024-01-22 Bo Lian, Xiaocheng Zhu, Zhaohui Du
Design load and vibration for parked conditions are gaining in importance for large-scale modern wind turbines with increasing flexibility, especially edgewise vibration when the blade is at a high angle of attack. In this work, flow-induced vibration of the wind turbine airfoil at 90 degrees of attack angle is studied with the fluid-structure interaction (FSI) simulation. The unsteady aerodynamic
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Wakes and secondary structures past stator wheel in test turbine VT-400 observed by PIV Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2024-01-17 Daniel Duda, Marek Klimko, Petr Milčák, Matěj Jeřábek, Václav Uruba, Vitalii Yanovych, Pavel Žitek
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Study on the steady-oscillatory transition of three-dimensional (3D) natural convection via Hopf bifurcation Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2024-01-22 Jingkui Zhang, Jiapeng Chang, Miao Cui, Yi Fan, Qifen Li, Cheng Peng
The transition from steady-state flow to periodic oscillatory flow for the natural convection by Hopf bifurcation is investigated in a three-dimensional (3D) cavity. The spectral collocation method (SCM) in combination with the artificial compressibility method (ACM), which is developed by ourselves as a numerical method SCM-ACM with high accuracy, is employed to solve the governing equations directly
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Direct numerical simulation of laminar, transitional and turbulent radially inward flow between closely spaced corotating disks Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2024-01-15 S. Klingl, S. Lecheler, M. Pfitzner
This study describes direct numerical simulation (DNS) of radially inward spiralling corotating disk flow with a narrow disk spacing, using the open source solver Nek5000 and the supercomputer SuperMUC-NG at Leibniz Supercomputing Centre. Knowledge about laminar and turbulent regime boundaries in this flow scenario is important for modelling and performance prediction of friction turbines. Simulations
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Corrigendum to “The role of Brinkmann ratio on non-Newtonian fluid flow due to a porous shrinking/stretching sheet with heat transfer” [Eur. J. Mech. B Fluids 92 (2022) 153–165] Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2024-01-16 U.S. Mahabaleshwar, A.B. Vishalakshi, Martin Ndi Azese
Abstract not available
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Impact process of a droplet on solid surfaces: Influence of surface wettability using lattice Boltzmann method Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2024-01-13 Salaheddine Channouf, Mohammed Jami, Ahmed Mezrhab
This research employed the pseudopotential multi-relaxation times lattice Boltzmann method to investigate the impact process of a droplet on solid surfaces, focusing on the influence of surface wettability for three different Reynolds numbers Re = 100, 200, and 500). Initially, the impact process is studied on both hydrophobic and hydrophilic surfaces, revealing distinct behaviors characterized by
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Time-resolved characteristics of oscillatory particle-laden air flow in a realistic human airway model Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2024-01-11 J. Jedelsky, F. Lizal, M. Jicha
Human airways represent a complex flow system with a spatially and temporally variable character of air flow during respiration. In this paper, we experimentally studied the oscillatory flow of air with monodispersed micron-sized liquid particles in a transparent, anatomically realistic model of human upper airways and several bronchi generations using phase-Doppler anemometry (PDA). The PDA provided
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Unsteady double-diffusive Brinkman–Bénard convection in cylindrical enclosure saturated with hybrid bi-viscous Bingham nanoliquid Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2024-01-11 , Y.D. Sharma, O.P. Yadav
This paper aims to present an analytical as well as a comparative study to investigate the effect of the Brinkman porous medium on the onset of regular and chaotic motion in cylindrical enclosures of different heights. The hybrid bi-viscous Bingham nanoliquid is considered as the working fluid. Modified Brinkman–Buongiorno and bi-viscous Bingham fluid models are incorporated to obtain the flow governing
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Study on the hydrodynamics of the helix with non-uniform helical radius in viscoelastic fluid at low Reynolds number Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2024-01-05 Wenbo Wu, Jiabao Wang, Leilei Chen, Shujie Jiang, Yilin Qu
Bacteria exhibit swimming behavior through the rotation of helical flagellar filaments, a common mode of propulsion for artificial micro-swimmers as well. However, most studies have focused on helical filaments with a uniform radius, leaving limited research on filaments with nonuniform radii. This paper presents a simulation of the hydrodynamics of a rotating helical filament with a nonuniform radius
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Assessment of the effectiveness of stall delay and tip loss corrections for the simulation of small propeller performance with Virtual Blade Model Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2024-01-05 Lorenzo Stabeli Diehl, José Gustavo Coelho
The powertrain efficiency of most small unmanned air vehicles (SUAVs) depend on the aerodynamic performance of multiple propellers, which must be modelled before its optimisation. To predict propeller performance while capturing interaction effects not accountable for by momentum theories, the Virtual Blade Model (VBM) can be used at much lower costs than conventional Computational Fluid Dynamics (CFD)
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Lattice Boltzmann modelling of multicomponent and multiphase flow with high density ratio Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2024-01-03 Qian Yang, Xiaolong He, Haonan Peng
Thermodynamic consistency is a key factor in heat and mass transfer simulation. A modified lattice Boltzmann pseudopotential model with the ability to simulate multiphase and multicomponent flow with a large density and viscosity ratio is proposed. Relative to a model using the exact difference method, a better thermodynamic consistency is obtained through introducing an improved external force term
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Influence of turbulent coherent structures on the performance and wake of a wind turbine Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2024-01-06 Yan Wang, Ronghu Guan, Liang Wang, Pan Lu
Wind energy in the atmospheric boundary layer serves as the primary source for energy absorption and structural load on wind turbines. However, the impact of turbulent coherent structures on the aerodynamic performance and wake characteristics of wind turbines has not been comprehensively evaluated. In this study, the proper orthogonal decomposition (POD) method is employed to assess the influence
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Stability analysis of sheared thermal boundary layers and its implication for modelling turbulent Rayleigh–Bénard convection Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2024-01-02 Mathieu Creyssels, Denis Martinand
Predicting the heat flux through a horizontal layer of fluid confined between a hot bottom plate and a cold top one has always spurred theoretical, numerical and experimental work on Rayleigh–Bénard convection. Customarily, the Nusselt number (the heat flux in non-dimensional form) has been modelled in the form of one or several power-laws of three parameters, the Rayleigh, Prandtl and Reynolds numbers
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Outflow of a supersonic overexpanded air jet into a water Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2023-12-30 Vladislav Emelyanov, Konstantin Volkov, Mikhail Yakovchuk
Numerical simulation of the underwater outflow of a supersonic overexpanded air jet is considered. The calculations are carried out in an unsteady three-dimensional formulation with a hybrid approach using Reynolds-averaged Navier–Stokes equations for nozzle flow and large eddy-simulation for jet flow. The calculation of the interaction of a gas with a liquid is performed with a volume of fluid, which
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Sensitivity analysis for a thermohydrodynamic model: Uncertainty analysis and parameter estimation Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2023-12-29 Camilla Fiorini, Maria Adela Puscas, Bruno Després
This paper proposes an efficient computational strategy to deal with uncertainty propagation problems for the Navier–Stokes equations coupled with a temperature equation based on a sensitivity analysis technique model. Sensitivity analysis allows one to investigate how the model response in a point is affected by a change in the boundary conditions on the temperature, the heat capacity, the thermal
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Comparison of surface tension models for the simulation of two-phase flow in an ISPH-FVM coupling method Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2023-12-29 Yixiang Xu, Gang Yang, Dean Hu
In the simulation of two-phase flow dominated by surface tension, accurate surface tension modeling is beneficial to better reproduce and understand the mechanism of interphase flow. In this paper, based on an ISPH-FVM coupling framework, three different surface tension models are implemented and tested respectively, including the generally used continuum surface force (CSF) model, the continuous surface
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Correlation between skin friction and enstrophy convection velocity in near-wall turbulence Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2023-12-23 Tianshu Liu, Tao Chen, Massimo Miozzi
The enstrophy convection velocity (denoted by uΩ) in the evolution equation of the boundary enstrophy is proportional to skin friction (denoted by τ) in an incompressible viscous flow, which can be determined globally as an optical flow problem from a time sequence of the boundary enstrophy fields. The correlation coefficient between |uΩ| and |τ| is evaluated in a turbulent channel flow at the friction
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Subcritical transition of the Stokes layer induced by wall surface roughness Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2023-12-19 Wei Kong
Wall defect is an important reason for the Stokes layer transition. The present study investigates the transition of the Stokes layer induced by wall surface roughness under subcritical Reynolds numbers, which is lower than the critical Reynolds number of the global neutral curve. A pseudo-spectral numerical method is utilized to simulate the interactive effects of different parameters related to surface
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M4 WEC development and wave basin Froude testing Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2023-12-19 Peter Stansby, Samuel Draycott
The M4 wave energy converter (WEC) is a moored, multi-float, multi-PTO (power takeoff), multi-mode, attenuator-type system designed to be capable of order MW capacity. The strategy is first described with technical requirements. Wave basin testing was undertaken to demonstrate the system and validate linear diffraction-radiation modelling, used for initial assessment and to generalise the configurations
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Off-design performance analysis of a radial fan using experimental, computational, and artificial intelligence approaches Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2023-12-14 Kowsar Moradihaji, Majid Ghassemi, Mahdi Pourbagian
Radial fans play a critical role as indispensable turbomachines in various industrial sectors. However, the conventional manufacturing process for these fans is often characterized by its resource-intensive and time-consuming nature. Traditionally, computational fluid dynamics (CFD) has been the go-to method for predicting and analyzing the performance of radial fans at different geometrical and operational
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Propagation of nonlinear surface waves over non-periodic oscillatory bottom profiles Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2023-12-17 Deepali Goyal, Tapan Kumar Hota, S.C. Martha
The effect of non-uniform, oscillating bottom profiles on a two-layer stable density stratification model has been examined using the method of weakly non-linear analysis. The study of bottom profiles in the context of two-layered stratified fluids has focused on three specific types: (a) profiles that exhibit a monotonically decreasing pattern, (b) profiles that decay exponentially, and (c) profiles
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Detection of erosion damage on airfoils by means of thermographic flow visualization Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2023-12-13 Friederike Jensen, Michael Sorg, Axel von Freyberg, Nicholas Balaresque, Andreas Fischer
Cavity-type defects on a wind turbine rotor blade due to erosion lead to an sub-optimal boundary layer flow behavior and result in a reduced annual energy production. To enable an indirect defect detection from far distances, with no contact and no wind turbine stop, the thermographic visualization of the defect wake flow is studied. Experimental investigations and complementary flow simulations on
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The flow characteristics for gas jet in liquid crossflow with special emphasis on the vortex-cavity interaction Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2023-12-13 Yafei Lv, Biao Huang, Taotao Liu, Haipeng Wei
The objective of this paper is to investigate the complex three-dimensional vortex structures created by the interaction of gas jet with liquid crossflow. A high-speed camera technique is used to record the evolution patterns of the jet cavity. High-precision numerical methods with the Chorin projection method and volume of fluid method (VOF) are employed to understand the complex flow features associated
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Deep reinforcement learning-based active control for drag reduction of three equilateral-triangular circular cylinders Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2023-12-09 Ning Chen, Ruigang Zhang, Quansheng Liu, Zhaodong Ding
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Passive elimination of flow-induced forces and vibrations of a circular cylinder using a slit Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2023-11-27 Ussama Ali, Anas Ghannam, Md Islam, Isam Janajreh
Here, passive flow control technique of incorporating a slit through a circular structure is utilized to dampen the flow-induced vibration (FIV). The study is segregated into two main sections, one where the effect of slit width ratio (S/D) and Reynolds number (Re) is investigated on the fixed stationary cylinder, and the other where the effect of slit size is explored on the behavior of the elastically
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Effect of variable viscosity, porous walls and mixed thermal boundary condition on the onset of Rayleigh-Bénard convective instability Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2023-11-28 Vinit Kumar Tripathi, Amit Mahajan, Rashmi Dubey
In this paper, we have studied the criteria for the onset of instability in the Rayleigh-Bénard convection problem, by considering a fluid layer confined between two infinitely extended rough boundaries, which are subjected to mixed-type thermal boundary conditions, physically representing the imperfectly conducting boundaries. The rough boundaries are assumed to be shallow porous layers with different
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The analytical solutions of the Riemann problem to 1-D non-ideal flow of dusty gas with external force Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2023-11-23 , L.P. Singh
This work focuses on the analytical solution to the Riemann problem (RP) for a 1-D non-ideal flow of dusty gas with external force. Here it is presumed that external force is a continuous function of time. We explicitly obtain the elementary wave curves to 1-D non-ideal flow of dusty gas with external force and determine these wave curves in form of characteristics. Exhaustive calculations were performed
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An improved van der Pol wake oscillator model for a 1DOF circular cylinder undergoing vortex induced vibrations Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2023-11-20 Michel Hardika, Chris Morton, Robert J. Martinuzzi
An optimization procedure is presented for prescribing the empirical coupling parameters of a modified coupled van der Pol (VDP) wake oscillator and mass–spring–damper system for a one degree of freedom (1DOF) circular cylinder system undergoing vortex induced vibrations (VIV). This approach allows for the generalization of the traditional VDP model to cover a large VIV parameter range. The procedure
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Suppressing vortex generation in ferrofluidic Couette flow via alternating magnetic fields Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2023-11-20 Sebastian A. Altmeyer
We illustrate how an alternating magnetic field can restrict and suppress the generation of vortex formation in ferrofluidic Couette flow. Therefore, the initial rotating outer cylinder (inner cylinder at rest) is brought to an abrupt stop, which results in the generation of more complex vortex dynamics in the system, evolving out of the initially fully laminar flow regime. The generated vortex flow
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Numerical simulation of two-phase slug flows in horizontal pipelines: A 3-D smoothed particle hydrodynamics application Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2023-11-13 Massoud Rezavand, Xiangyu Hu
A fundamental difficulty of studying gas–liquid pipe flows is the prediction of the occurrence and characteristics of the slug flow regime, which plays a crucial role in the safety design of oil pipelines. Current empirical methods and one-dimensional computational models only achieve limited success. While 3-D numerical simulations are highly recommended, they have been very seldom used. We perform
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Scale law investigation of the curved boundary layer flow around a horizontal cylinder – for Pr <1 fluids Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2023-11-10 Yang Liu, Zhengping Ma
In this paper, the convective boundary layer flow that evolves on the external surface of a heated horizontal cylinder is investigated with the scaling analysis. Two thermal boundary conditions at the heated surface are considered: an isothermal and an iso-flux heating condition. The calculated data demonstrate that, similar to the extensively studied flat-plate boundary layer flows, development of
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Study on the effect of the canard on wide-speed range aerodynamic performance of the cuspidal waverider Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2023-11-04 Zhen-Tao Zhao, Zan Xie, Can-Can Zhou, Chen-Hang Wang, Wei Huang, Xu-ping Dai
As a type of wide-speed range waverider, the vortex lift waverider can make better use of the vortex lift characteristics to enhance the low-speed aerodynamic efficiency of the waverider. In order to study the influence of the canard on the wide-speed-range aerodynamic performance of the vortex lift waverider, this paper takes the cuspidal waverider configuration as the benchmark configuration for
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Effect of radius ratio on the instabilities in a vaneless diffuser Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2023-11-07 Meng Fan, Antoine Dazin, Gérard Bois, Francesco Romanò
The prominent features of the primary instabilities of a turbulent source flow between finite-span parallel rings with spatially modulated inflow conditions rotating at angular rate Ω are investigated. Two different two-dimensional instabilities that occur at large (αQ≳1.00) and low (αQ≲0.65) flow rates have been traced back to two different physical mechanisms related to jet-wake and mean-core flow
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Flow Rectification in a Micro-Nanochannel Junction: Interplay of Channel Geometry and Interfacial Properties for Directional Transport Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2023-11-04 Nilanjan Mondal, Chirodeep Bakli
The linear correspondence between flow rate and pressure drop for low Reynolds number hydrodynamics is often a constraint for the realization of miniaturized fluid circuits with selective junctions. Here we devise a micro-nanochannel junction with the directional flow in the nanochannel achieved by a combination of junction geometry and wall functionalization. The system can be compared to a fluid
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Laminar flow in a channel bounded by porous/rough walls: Revisiting Beavers-Joseph-Saffman Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2023-10-31 Essam Nabil Ahmed, Alessandro Bottaro
The fully developed, steady, incompressible, laminar flow in a channel delimited by rough and/or permeable walls is considered. The influence of the micro-structured bounding surfaces on the channel flow behavior is mimicked by imposing high-order effective boundary conditions which stem from homogenization theory and do not contain empirical parameters. A closed-form solution of the Navier–Stokes
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Generalized mean state of the isothermal Darcy–Benard problem and its instability onset Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2023-11-04 Mustafa Turkyilmazoglu, Faisal Z. Duraihem
Thermally-driven natural convection is theoretically explored in the present work within a porous layer with respect to the Darcy’s law. The usual non circulating basic cellular flow between two infinitely long horizontal Darcy porous plates leads to generalized basic state considering the isothermal boundary conditions leading to the Hadley flow configuration. Such a motion is governed by a circulatory
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Experimental study of the stability of crescent barchan shape in subaqueous dune evolution in unsteady water flow Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2023-10-29 , Ye Chong, Yuanwei Lin, Nan He, Yang Zhang, Xin Gao
A water tunnel experiment adopting the frequency conversion technology is conducted to investigate the evolution of subaqueous barchan dune driven by the periodic water flow. The kinematic and morphological characteristics of the barchan dune evolution are derived through the imaging processing. Results exhibit a good correlation between the dune kinematics and the periodic variation of water flow
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Water droplets jumping on a surface due to hydrophobicity variation: Computational modelling approach Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2023-10-27 Mohammad Sadeq Alizadeh, Amir Lohrasebi, Jürgen Rühe
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Effects of anisotropy on the geometry of tracer particle trajectories in turbulent flows Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2023-10-28 Yasmin Hengster, Martin Lellep, Julian Weigel, Matthew Bross, Johannes Bosbach, Daniel Schanz, Andreas Schröder, Florian Huhn, Matteo Novara, Daniel Garaboa Paz, Christian J. Kähler, Moritz Linkmann
Using curvature and torsion to describe Lagrangian trajectories gives a full description of these as well as an insight into small and large time scales as temporal derivatives up to order 3 are involved. One might expect that the statistics of these observables depend on the geometry of the flow. Therefore, we calculated curvature and torsion probability density functions (PDFs) of experimental Lagrangian
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Inelastic interactions between a small, intense dipole and a large, weak, neutral monopole Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2023-10-27 P. Roca Ramis de Ayreflor, A. Viúdez
Inelastic interactions between a small, intense dipole and a weak, neutral monopole in two-dimensional flows are analysed. The neutral vortex has vanishing exterior potential flow and the interactions involve the rotational flow of the vortices. It is shown that dipoles of small-size but large-amplitude, relative to the neutral vortex, may cross the vortex and scatter while leave the vortex stable
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Solidification of a liquid drop enclosing a bubble on an inclined surface Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2023-10-24 Nang X. Ho, Truong V. Vu
In the present paper, we report the numerical results of the solidification process of a liquid drop enclosing an air bubble, i.e., a hollow drop, on an inclined surface. The surface is tilted from 0° (corresponding to a horizontal surface) to 90° (corresponding to a vertical surface), and the contact angle of the drop ranges between 60° and 130°. The drop is deformed while solidification happens in
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Zero-frequency added mass of submerged bodies with near-surface effects Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2023-10-16 Bradford G. Knight, Sung Jun Won, Kevin J. Maki
The added mass of ships, submarines, and marine platforms is a primary quantity of interest to understand vessel dynamics and motion. For low-frequency maneuvers at low forward speed, the water surface acts as a wall and the added-mass depends on the proximity to the free-surface. In this paper a method for efficiently determining the full six-degree-of-freedom zero-speed added-mass tensor is presented
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Roughness induced transition delay in a swept-wing boundary layer in presence of freestream disturbances, Part 1: Turbulence effects Eur. J. Mech. B Fluids (IF 2.6) Pub Date : 2023-10-12 V.I. Borodulin, A.V. Ivanov, Y.S. Kachanov
Results of experimental investigations on control of the laminar–turbulent transition location in a 45-degree swept-wing boundary layer by the distributed micro-sized roughness (MSR) elements in presence of freestream perturbations are discussed in this two-part work. Part 1 of this study (the present paper) is devoted to the freestream turbulence effects, while Part 2 (Borodulin et al., 2023) concentrates