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The convective instability of the boundary-layer flow over a rotating cone in and out of a uniform magnetic field Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2021-01-10 L. Ullah; A. Samad; A. Nawaz
We present convective instability analyses of the boundary-layer flows originated over cones (with half-angle ψ≤90∘) rotating in an otherwise still conducting fluid. A uniform magnetic field (with magnetic strength parameter, m≥0) is acting normally on the surface of each cone. In the non-magnetic case of cones, comparison of present results with existing experimental and theoretical studies lead *to
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A data-driven artificial neural network model for predicting wind load of buildings using GSM-CFD solver Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2021-01-19 Jianbing Sang; Xingda Pan; Tao Lin; Weiguang Liang; G.R. Liu
Wind load prediction is critical to the design of buildings, especially skyscrapers, because wind-induced dynamic loads and vibrations can often be a major concern that dominates the design. This paper presents a real-time wind load predictor for buildings by training an artificial neural network, with big data generated from a well-established software package for computational fluid dynamics (CFD)
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Numerical investigation on the formation mechanism of ventilated cavitation with gas jet cavitator Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2021-01-18 Ju Liu; Junwei Yu; Zheng He; Hang Yu; Kuo Yuan; Yonghui Guo
The complexity of the formation mechanism of ventilated cavities makes it difficult to be explored experimentally. In this study, the formation mechanism of cavity regimes around a gas jet cavitator were first numerically predicted using the partially averaged Navier–Stokes (PANS) and homogeneous free surface models. The numerical framework was validated by comparing the numerical predictions with
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Wavelet based numerical approach of non-classical moving boundary problem with convection effect and variable latent heat under the most generalized boundary conditions Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2021-01-12 Jitendra; K.N. Rai; Jitendra Singh
The major goal of this article is to analysis a mathematical model of a non-classical one-dimensional moving boundary problem in the presence of convection effect when one surface subjected to the most generalized boundary conditions. The control function describes the cooling and heating effect depends on the evolution of heat flux at x=0. The thermo-physical properties are assumed to be constant
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Experimental investigation of upstream cube effects on the wake of a wall-mounted cylinder: Wake rising reduction, TKE budget and flow organization Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2021-01-21 Maëlys Magnier; Philippe Druault; Grégory Germain
The development of Marine Renewable Energy based on tidal currents at a selected area needs to first analyze the flow characteristics and thus the bathymetry induced turbulence in this area. The present study aims to investigate turbulence characteristics around two wall mounted obstacles in tandem, which represent seabed obstacles in a high Reynolds number flow. 2D planar PIV measurements are performed
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Global stability analysis of axisymmetric boundary layer on a slender circular cone with the streamwise adverse pressure gradient Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2021-01-20 Ramesh Bhoraniya; Zahir Hussain; Vinod Narayanan
This paper presents a global stability analysis of the boundary layer developed on a slender circular cone. The direction of the base flow is towards the apex of a cone, and the pressure gradient is positive (adverse) in the flow direction. The decelerating base flow is non-parallel and non-similar. The increased semi-cone angle increases the adverse pressure gradient in the flow direction. For a given
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Hydrodynamic interactions between two side-by-side Janus spheres Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2021-01-19 Manish Dhiman; Raghvendra Gupta; K. Anki Reddy
Janus spheres are heterogeneous amphiphilic particles having partially slippery and partially sticky surface. As a result, hydrodynamic forces such as drag and lift on a Janus sphere is different from that on a homogeneous sphere. Several applications of Janus particles require high particle concentration in a continuous fluid medium making the interactions between them inevitable. Therefore, in this
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Exact solution and instability for geophysical waves in modified equatorial β-plane approximation with and without centripetal forces Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2021-01-18 Dong Su; Hongjun Gao
In the paper, we first present an exact solution for geophysical internal waves with centripetal forces and geophysical edge waves without centripetal forces in modified equatorial β-plane approximation. Then we apply the short-wavelength perturbation method to show an instability threshold for geophysical internal waves propagating eastward with centripetal forces and geophysical edge waves without
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Thermo-hydrodynamic analysis of drop impact calcium alginate gelation process Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-12-28 Krishnayan Haldar; Sudipto Chakraborty
The phenomenon of calcium alginate gel formation from sodium alginate drop impact on calcium chloride liquid pool generates enormous scientific interest. The present work features on the investigation of interfacial heat transfer during sodium alginate drop impact on a heated calcium chloride liquid pool. The liquid pool has been heated at different temperatures varying from 20 °C to 70 °C. The drop
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Axisymmetric slow viscous liquid flow around a spherical bubble translating in a circular tube Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2021-01-06 Jae-Tack Jeong
We investigate the axisymmetric slow viscous liquid flow around a spherical bubble located on the axis of a long circular tube analytically based on the Stokes approximation. The bubble translates along the axis of the tube with a constant velocity within Hagen–Poiseuille flow flowing far from the bubble. The translating velocity of the bubble and mean velocity of the Hagen–Poiseuille flow are given
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On the flow induced by a rotating and radially stretching disk Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-12-26 Eugen Magyari; Patrick Weidman
The flow induced by a simultaneously rotating and radially stretching disk is revisited in this paper. The steady solution is given by a power-series of exponentials including the governing parameter of the problem c=Ω∕s, which is the ratio of the angular velocity of rotation Ω and the strain rate of stretching s . Since the series satisfy the far field conditions automatically, the boundary value
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Higher-order derivatives of the Green function in hyper-singular integral equations Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-12-28 Hui Liang; Yanlin Shao; Jikang Chen
Hyper-singular integral equations are often applied in the frequency-domain wave diffraction/radiation analyses of marine structures with thin plates or shell sub-structures. Their numerical solutions require the higher-order derivatives of the free-surface Green function featuring hyper-singularity, and hence the corresponding evaluation is very challenging. To circumvent the associated numerical
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On constant influx gravity current propagating over a porous bottom Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-12-26 T. Zemach
Consider the propagation of a gravity current (GC) sustained by a source of a fluid of density ρc and constant volume rate Q into an ambient fluid of height H and density ρa over a permeable bed. The porous layer of a given length Δxp is located at the bottom of the container. Assume Boussinesq and large Reynolds-number flow. We present a new model for the prediction of the thickness h and depth-averaged
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Flow around a surface-mounted finite circular cylinder completely submerged within the bottom boundary layer Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-12-18 Di Zhang; Liang Cheng; Hongwei An; Scott Draper
This paper presents a detailed investigation on the flow characteristics and the bed-shear-stress distribution around a finite circular cylinder at a fixed Reynolds number (Re = 2 ×104) and seven aspect ratios (AR = 0.5∼6) by solving the Reynolds Averaged Navier–Stokes (RANS) equations. It is found that, for a moderate Reynolds number and a relatively large boundary-layer thickness, the time-averaged
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Lattice Boltzmann modeling of a gravity-driven sliding droplet under a dynamic wetting regime Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-12-30 Nursultan Zhumatay; Bagdagul Kabdenova; Ernesto Monaco; Luis R. Rojas-Solórzano
This work presents the numerical modeling of a sliding droplet on a vertical smooth wall under hydrophobic and hydrophilic conditions using the multiphase Shan–Chen Lattice Boltzmann Model (SC-LBM). The gravitational action above the interfacial force was introduced through the variation of the Bond number and contact angle between droplet, solid surface and surrounding fluid. A critical Bond number
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Numerical study of effects of gap and incident wave steepness on water resonance between two rectangular barges Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-12-10 Yajie Li; Xikun Wang
A 2D numerical wave tank based on the fully nonlinear potential flow theory is built to simulate the water resonance between two fixed rectangular barges, focusing on the influence of the gap width and incident wave steepness on the liquid motion and hydrodynamic forces on the surrounding bodies. The initial boundary value problem (IBVP) for disturbed velocity potential is solved through boundary element
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Slow rotation of a spherical particle in an eccentric spherical cavity with slip surfaces Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-12-16 Chin Y. Chou; Huan J. Keh
A semi-analytical study of the steady flow around a spherical particle rotating in an incompressible Newtonian fluid inside an eccentric spherical cavity with slip surfaces about their common diameter is presented at low Reynolds numbers. To solve the Stokes equation, a solution consisting of the general solutions in two systems of spherical coordinates is employed and the boundary conditions are fulfilled
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Consistent section-averaged shallow water equations with bottom friction Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-12-22 Victor Michel-Dansac; Pascal Noble; Jean-Paul Vila
In this paper, we present a general framework to construct section-averaged models when the flow is constrained – e.g. by topography – to be almost one-dimensional. These models are consistent with the two-dimensional shallow water equations. After rewriting the two-dimensional shallow water equations in a suitable set of coordinates allowing to take care of a meandering configuration, we consider
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Application of homotopy perturbation method in inverse analysis of Jeffery–Hamel flow problem Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-12-08 Uddhaba Biswal; S. Chakraverty; B.K. Ojha
Different authors have studied incompressible fluid flow through two inclined planes. Previous authors have used different numerical methods to find the velocity profile of fluid flow for Jeffery–Hamel problem, which is known as the forward problem. It may be interesting to study the inverse problems related to the above. In that case, the velocity profile may be known and then the angle between two
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A MEMS-based methodology for measurement of effective density and viscosity of nanofluids Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-12-07 Mina Ghanbari; Ghader Rezazadeh
Due to the importance of the usage of nano-technology based fluids in several industrial processes, the presented research deals with mathematical modeling of a comb-drive MEMS-based sensor for determinations of the physical properties of nanofluids. The proposed sensor is made up of a driving comb, sensing comb, and a sensing plate. It is actuated longitudinally via the electrostatic force created
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The mechanism of vortex bifurcation vis-à-vis axial switching in rectangular synthetic jets Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-12-08 Abhay Kumar; Arun K. Saha; Pradipta K. Panigrahi; Ashish Karn
The present study investigates the vortex dynamics of the rectangular shaped synthetic jet and reports the occurrence of vortex ring bifurcation along with other reported modes such as axial switching and the vortex suction. The novel finding of vortex ring bifurcation of rectangular synthetic jets has been observed without any other mode of excitation except the periodic axial actuation. The experiments
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Modal decomposition methods for distributed excitation force field on tube bundle in cross flow Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-11-28 Qi Zhang; Pingjian Ming; Wenping Zhang
To rapidly and accurately identify the characteristics of the distributed force and reconstruct the force field on tube bundles in a cross flow, modal decomposition methods for a three-dimensional turbulent flow are studied. This is done with proper orthogonal decomposition (POD), dynamic mode decomposition (DMD), and the regularization method for DMD. A 3-D turbulent cross flow computational fluid
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Linear stability of a fluid mud–water interface under surface linear long travelling wave based on the Floquet theory Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-12-02 Jiebin Liu; Rubing Ma; Yidan Yuan; Xiaoming Yang; Weimin Ma
The Floquet theory is combined with the unsteady Orr–Sommerfeld equations for the first time to model the linear stability of a fluid mud–water interface under the influence of a linear long travelling wave (or linear shallow water wave). The modelling results reveal three instability modes that could appear on the fluid mud–water surface: the Kelvin–Helmholtz (K–H) and finite-wavelength (F-W) instabilities
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Homann stagnation-point flow impinging on a biaxially stretching surface Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-12-02 Matthew R. Turner; Patrick Weidman
The normal impingement of axisymmetric Homann stagnation-point flow on a surface executing perpendicular, planar, biaxial stretching is studied. The flow field generated is an exact solution of the steady, three-dimensional Navier–Stokes equations in the form of a similarity solution. It is shown that two sets of dual solutions exist, forming four different branches of steady solutions. For sufficiently
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Resonance of long waves around a circular island and its relation to edge waves Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-11-24 Xiaojing Niu
As long waves propagate over an island, wave energy can be trapped in the shallow water near the coastline due to the effect of refraction and diffraction. However, in some particular situations extremely huge near-shore waves can be excited due to the resonance of edge waves. This study focuses on the occurrence condition of the resonance phenomenon, and mainly investigates the effects of geometric
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Complete theory of the elastic wall jet: A new flow geometry with revisited two-phase nanofluids Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-11-21 Amin Jafarimoghaddam; Mustafa Turkyilmazoglu; A.V. Roşca; I. Pop
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Acoustic streaming outside spherical particles and parameter analysis of heat transfer enhancement Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-11-24 Gen-shan Jiang; Yan-feng Yang; Yue-chao Liu; Yu Jiang
Acoustic streaming effects can play an important role for promoting heat and mass transfer. Considering the viscous loss inside the viscous boundary layer on the particles surface, a numerical model for the acoustic streaming outside a two-dimensional spherical particle in a plane standing wave sound field is established, and the distribution characteristics of the acoustic streaming outside the particles
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Entropy generation in electromagnetohydrodynamic water based three Nano fluids via porous asymmetric microchannel Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-11-17 S. Noreen; S. Waheed; DC. Lu; A. Hussanan
Nanofluids are of immense importance to the researchers as they have significant uses industrially due to their high heat transfer rates. This new model is employed to examine the electroosmotic flow of magnetohydrodynamic nanofluids through an asymmetric microfluidic channel. Microchannel flow is driven by the electroosmosis and peristalsis mechanisms. Nanoparticles (copper, alumina and titania) with
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Experimental characterization of dynamic behavior of single bubble breakage in an agitated tank Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-11-14 Basim O. Hasan; Muayad F. Hamad; Hasan Sh. Majdi; Mustafa M. Hathal
Experimental tests for characterizing bubble breakage dynamics in different locations of a stirred tank with a 6-bladed impeller were carried out for a range of impeller Reynolds number (Re) using water as a continuous phase. The dynamic behavior of the bubble from the injection point until arriving at the impeller region was studied by using a high speed imaging method. The deformation behavior, local
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Flow and mixing characteristics of dual parallel plane jets subject to acoustic excitation Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-11-12 Sanjay Kumar; Rong Fung Huang; Ching Min Hsu
The effects of jet pulsation intensity and excitation Strouhal number on the flow and dispersion characteristics of dual parallel plane jets at a low Reynolds number of 200 were experimentally studied so that the transition from laminar to turbulence was focused. A hot-wire anemometer was used to record the jet velocities. The flow patterns were obtained using the laser-light sheet assisted smoke flow
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Interaction of a pair of in-line bubbles ascending in an Oldroyd-B liquid: A numerical study Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-11-12 Mohammad Vahabi; Hamidreza Hadavandmirzaei; Babak Kamkari; Hesameddin Safari
In this paper, the interaction between two initially circular in-line bubbles during their rise in a viscoelastic liquid under gravity is numerically simulated by weakly compressible smoothed particle hydrodynamics (WC-SPH). The background fluid is assumed to obey Oldroyd-B rheological model and the surface tension between two phases is evaluated by continuum surface tension (CST) method. First, it
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Lid-driven cavity flow of sediment suspension Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-10-15 Chuong Nguyen Hoang-Trong; Cuong Mai Bui; Thinh Xuan Ho
A lid-driven cavity flow of kaolinite suspension is investigated using a numerical approach. The suspension with a kaolinite concentration in the range of 15–28.5wt% is modeled using Bingham–Papanastasiou approach. The cavity is of a rectangular shape and has different aspect (height-to-width) ratios, that is, 0.5 (shallow cavity), 1 (square cavity), and 2 (deep cavity). The width-based Reynolds number
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Kelvin–Froude wake patterns of a traveling pressure disturbance Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-11-08 Jonathan Colen; Eugene B. Kolomeisky
According to Kelvin, a point pressure source uniformly traveling over the surface of deep calm water leaves behind universal wake pattern confined within 39° sector and consisting of the so-called transverse and diverging wavefronts. Actual ship wakes differ in their appearance from both each other and Kelvin’s prediction. The difference can be attributed to a deviation from the point source limit
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Rotating flows regarded as point-mechanical motions in the complex domain Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-11-04 Eugen Magyari
It is shown that a large class of rotating disks flows described by an exact solution of the Navier–Stokes equations can be mapped on the mechanical motion of a point mass in the complex domain. The mathematical procedure, the physical features and the advantages of the point-mechanical approach are presented for von Kármán’s classical swirling flow and its magneto-hydrodynamic counterpart in detail
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Comment to “Atmospheric boundary layer modeling in a short wind tunnel” by Dan Hlevca and Mircea Deguratu, EJM/B Fluids, 79 (2020), 367-375 Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-09-28 Nicholas J. Cook
George Santayana’s aphorism “Those who cannot remember the past are condemned to repeat it” has never been more apposite than as applied to this paper. The paper rebutted here reproduces, without any form of acknowledgement, the method of reproducing characteristics of the atmospheric boundary layer (ABL) in a wind tunnel published in 1957 (Owen and Zienkiewicz, 1957). This method, together with the
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Restricted optimal paths to transition in a plane Couette flow Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-10-15 Frédéric Alizard; Lionel Le Penven; Anne Cadiou; Bastien Di Pierro; Marc Buffat
To identify laminar/turbulent transition paths in plane Couette flow, a variational formulation incorporating a restricted nonlinear (RNL) system that retains a single streamwise Fourier mode, is used. Considering the flow geometry originally used by Monokrousos et al. (2011) and Duguet et al. (2013) and the same Reynolds numbers (Re), we show that initial perturbations obtained by RNL optimizations
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Lattice Boltzmann simulation of the Rayleigh–Taylor Instability (RTI) during the mixing of the immiscible fluids Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-10-15 Kumara Ari Yuana; Bahrul Jalaali; Eko Prasetya Budiana; Pranowo; Adhika Widyaparaga; Indarto; Deendarlianto
The Lattice Boltzmann Method (LBM) was implemented to simulate the two-dimensional (2-D) Rayleigh–Taylor instability (RTI) during the mixing of the immiscible fluids. Two important parameters of the density and the viscosity as represented respectively by the Atwood and the Reynolds numbers were considered. In the calculation the density of two immiscible fluids was calculated by using the equation
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A new PDE-based resolution enhancement technique for the analysis of low SNR particle displacement images Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-10-14 Arman Mohseni
Speckle images have found multiple applications in image-based measurement techniques, where the objective of measurement is the estimation of speckle displacements between two often consecutive images. Depending on the characteristics of a measurement system and its measurands, the signal-to-noise ratio (SNR) of recorded images may become low and even marginal. One solution to improve the accuracy
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Assessment of multiple relaxation time-lattice Boltzmann method framework for non-Newtonian fluid flow simulations Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-10-17 Manju Bisht; Dhiraj V. Patil
A kinetic-theory based approach known as the lattice Boltzmann method (LBM) with multiple-relaxation-time (MRT) collision is employed to assess the non-Newtonian fluid models for standard two-dimensional benchmarks flow configurations. A two-dimensional nine-velocity square lattice (D2Q9) is used as a basic space-microscopic-velocity coupled LBM structure. The MRT-LBM formulation for the non-Newtonian
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Design and analysis of micro-nano scale nested-grooved surface structure for drag reduction based on ‘Vortex-Driven Design’ Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-10-21 Liyue Wang; Cong Wang; Shuyue Wang; Gang Sun; Bo You
Bioinspired grooved surface structure design has been widely used as an efficient passive flow control method in drag reduction. The total drag of plate with grooved surface structure can be decomposed into friction and pressure drag. In this paper, the relationship between them and the distribution of vortex structure in flow field has been analyzed for obtaining the drag reduction mechanism of grooved
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Transient dynamic analysis for the submerged gas jet in flowing water Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-09-25 Min Xiang; Xiaoyu Zhao; Houcun Zhou
Submerged gas jet is commonly encountered in underwater cutting, underwater jet-propulsion, liquid metal mixing and other applications. In this paper the transient dynamics for the high-speed submerged gas jet in a flowing water environment was investigated. The experiments were carried out in an open water tunnel which could achieve high degassing rate. The jetting flow rate was varied from subsonic
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Side wall boundary effect on the Rayleigh–Taylor instability Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-10-07 Junxiang Yang; Hyun Geun Lee; Junseok Kim
Rayleigh–Taylor instability (RTI) is a common phenomenon in daily life and in industrial application. Despite the long history of investigating the RTI with periodic boundary condition, there are only few studies for the RTI with no-slip side wall boundary condition. In fact, the RTI with the side wall boundary condition is more realistic physics. In this work, we investigate the side wall boundary
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Hydrodynamic instabilities in swirling flow under axial magnetic field Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-08-24 A. Laouari; B. Mahfoud; R. Bessaïh; A. Hadjadj
The present paper investigates numerically the hydrodynamic instabilities occurring in a cylindrical container filled with a conducting viscous fluid and submitted to an axial magnetic field. The axisymmetric swirling flow produced by rotation of the bottom disk, in which a vortex breakdown bubble occurred on the axis of symmetry. This flow structure represents one of the most important instabilities
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Numerical investigation of shedding dynamics of cloud cavitation around 3D hydrofoil using different turbulence models Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-09-30 Ju Liu; Junwei Yu; Zailin Yang; Zheng He; Kuo Yuan; Yonghui Guo; Yu Li
Turbulence modeling plays a crucial role in simulating unsteady characteristics of cavitation flows. Owing to the different theoretical backgrounds of partially averaged Navier–Stokes (PANS) and filter-based models (FBMs), the differences in their unsteady cavitation flow predictions are worth comparing. In this study, PANS and FBM were used to predict the cloud cavitation regime around a three-dimensional
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Flow behaviours and velocity fields of non-oscillating and transversely oscillating jets Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-09-22 Dinku Seyoum Zeleke; Rong Fung Huang; Ching Min Hsu
The near-field flow characteristics and jet fluid dispersion properties of non-oscillating and transversely oscillating jets issued from a fluidic oscillator were studied experimentally. A V-shaped fluidic oscillator was designed to induce transverse jet oscillations by merging two bifurcated alternatively issuing side jets. The characteristic flow patterns, evolution processes, velocities, vorticities
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Investigations into transient wakes behind a custom airfoil undergoing pitching motion Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-09-26 Vineeth V.K; Devendra Kumar Patel; Subhransu Roy; Srikanth Goli; Arnab Roy
The wake dynamics behind a sinusoidally pitching custom designed symmetrical airfoil is analyzed computationally. The effect of pitching frequency and pitching amplitude is investigated independently at a constant Reynolds number. The wake patterns are found to exhibit a transition from von Karman to reverse von Karman vortex street and from symmetric reverse von Karman vortex street to asymmetric
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VIV modelled using simplified cable dynamics coupled to sub-critical cylinder flow simulations in a moving reference frame Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-09-25 Lei Zhang; John Redford; Fikri Hafid; Jean-Michel Ghidaglia; Maxime Gueguin
This work focuses on the study of the phenomenon of vortex-induced vibrations in overhead lines under the effect of weak winds. Full three-dimensional simulation is not feasible because of the high length to width aspect ratios of the overhead lines. Thus a quasi-3D method based on strip theory is adopted in this work. This method decouples the system of interactions between the overhead line and the
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Effect of magnetic field on a microstretch fluid drop embedded in an unbounded another microstretch fluid Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-09-23 Shreen El-Sapa
The problem of an axisymmetric translational motion of an incompressible microstretch fluid past an immiscible stationary microstretch droplet in the presence of a uniform magnetic field is investigated. The inertial terms in the equations of motion are neglected, therefore the microstretch scalar function is uncoupled from the stream function and microrotation component. Analytical solutions are obtained
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Heat transfer in electrokinetic micro-pumps under the influence of various oscillatory excitations Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-09-18 Ali Jabari Moghadam
Thermal characteristics of time-periodic electroosmotic flow are analyzed in a micro-annulus under the influence of various alternating electric fields. Representative hydrodynamic and thermal quantities, i.e. volumetric flow rate and Nusselt number, demonstrate oscillatory behaviors approaching a quasi-steady state if few periods of time elapse. An important parameter named dimensionless frequency
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On dual solutions of the unsteady MHD flow on a stretchable rotating disk with heat transfer and a linear temporal stability analysis Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-09-18 G.M. Sarkar; B. Sahoo
The present paper is an extension of the work done by Fang and Tao (2012) in the presence of a magnetic field. The external magnetic field is applied normal to a stretchable disk surface and heat is transferred from the disk surface to the ambient fluid which gives a new family of unsteady viscous flow over a stretchable rotating disk with deceleration. The Navier–Stokes equations and the energy equation
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Velocity decomposition approach for steady incompressible flow around bluff bodies using a transpiration auxiliary surface Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-09-14 Lucas Lincoln Fonseca Soares; Nelson Manzanares-Filho; Ramiro Gustavo Ramirez Camacho
Viscous/inviscid interaction methods employing velocity decomposition have been explored for reducing computational costs in external flow problems. For this, viscous simulations are made in reduced computational domains encompassing the rotational flow region. The coupling of potential and viscous solutions is made on a boundary of negligible vorticity, assessed by means of sampling lines normal to
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Motion of a neutrally buoyant elliptical particle in a lid-driven square cavity Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-09-14 Junjie Hu
The motion of the solid particles in the enclosed cavity is important, to investigate the interaction between the motion of the solid particles and the fluid flow, the motion of a neutrally buoyant elliptical particle in a lid-driven square cavity is studied with the lattice Boltzmann method. To understand, predict and control the motion of the elliptical particle, the effects of the aspect ratio,
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Vortex-induced vibrations of an elastically mounted disk: The characteristics of wake and trajectory Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-09-18 Conghui Li; Cong Wang; Weixue Xia; Chengju Zhang
Vortex-induced vibration (VIV) of an elastically supported disk is investigated computationally using large-eddy-simulation (LES). The disk motion is constrained to move in the transverse plane vertical to the free stream. Two sets of simulations are conducted at Re=165 and 210 over the reduced velocity range 3≤UR≤7.5 respectively. The disk shows a highly periodic large-amplitude vortex-induced vibration
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Oblique stagnation flow towards a rotating disc Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-09-11 Suman Sarkar; Bikash Sahoo
This work endeavours to study the problem of axisymmetric oblique stagnation point flow above a rotating disc. An external flow impinges obliquely on a disc when the disc is rotating with constant angular velocity. Suitable similarity variables are introduced, for the first time, to transform the governing Navier–Stokes equations into a highly nonlinear system of ordinary differential equations, governed
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Study on the flow structure behind a freely falling annular disk using proper orthogonal decomposition Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-09-11 Dianfang Bi; Yingjie Wei; Raf Theunissen; Hao Xu
The applications of freely falling bodies in steady water or air have been widely observed in nature, from the dispersing of a tree seed to the re-entry of a space shuttle. Disparate objects exhibit particular falling styles which have been studied for a long time. However, the mechanism behind this extensive phenomenon has not been clearly understood. In this paper, we investigate experimentally the
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Linear stability and nonlinear evolution of a polar vortex cap on a rotating sphere Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-09-12 Sun-Chul Kim; Sung-Ik Sohn
In this paper, we study the stability of a barotropic polar vortex cap on a rotating sphere. We present the linear stability analysis of the polar vortex cap, approximating the piecewise-continuous vorticity distribution by zonal bands of uniform vorticity. We investigate the dependence of the flow stability on the location of the vortex cap, modes of perturbation and rotation speed. The linear stability
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Structure turbulent flow behind a square cylinder with an angle of incidence Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-09-06 Vitalii Yanovych; Daniel Duda; Václav Uruba
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Role of fractal–fractional derivative on ferromagnetic fluid via fractal Laplace transform: A first problem via fractal–fractional differential operator Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-09-03 Kashif Ali Abro
A deformity of magnetic field discloses that different particle of ferrofluid exhibits different pattern to accumulate more closely with strong magnetic properties; this is because of the existence of a homogeneous ferromagnetic liquid. In this context, the Newtonian fluid (ordinary liquid) is magnetized by dispersing into porous media. A mathematical model for ferromagnetic fluid is developed by means
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Swimming of a uniform deformable sphere in a viscous incompressible fluid with inertia Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-09-03 B.U. Felderhof, R.B. Jones
The swimming of a deformable uniform sphere is studied in second order perturbation theory in the amplitude of the stroke. The effect of the first order reaction force on the first order center of mass velocity is calculated in linear response theory by use of Newton’s equation of motion. The response is characterized by a dipolar admittance, which is shown to be proportional to the translational admittance
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Numerical investigations on transitional flows around forward and reversed hydrofoils Eur. J. Mech. B Fluids (IF 2.131) Pub Date : 2020-08-30 Lei Shi, Yefang Wang
The laminar–turbulence transition phenomenon widely exists on the surface of many energy equipment, which is deserved to be studied because of the complex mechanics and some induced undesirable consequences. The goal of present work is to investigate the transitional flows around the forward and reversed hydrofoils at different incidences using the SST γ-Re˜θt transition model, with special emphasis
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