# Fluid Dynamics Research Journal Impact Factor & Information

Publisher: Nihon Ryūtai Rikigakkai, IOP Publishing

## Impact Factor Rankings

2015 Impact Factor Available summer 2015 0.656 0.758 0.673 1.089 0.897 1.012 0.935 0.538 0.58 0.62 0.766 0.567 0.438 0.427 0.451 0.394 0.472 0.663 0.535 0.313 0.521 0.338

## Impact factor over time

Impact factor
.
Year

5-year impact 1.03 8.80 0.21 0.00 0.49 Fluid dynamics research (Online), FDR 1873-7005 38873608 Document, Periodical, Internet resource Internet Resource, Computer File, Journal / Magazine / Newspaper

## Publisher details

• Pre-print
• Author can archive a pre-print version
• Post-print
• Author can archive a post-print version
• Conditions
• Pre-print on author's personal website, repository or arXiv.
• Pre-print can not be updated after submission
• Post-print on author's personal website immediately
• Post-print on institutional repository, subject-based repository, PubMed Central or third party eprint servers after 12 months embargo
• Publisher's version/PDF cannot be used
• Published source must be acknowledged with citation
• Must link to publisher version with DOI
• Set statements to accompany different versions (see policy)
• Publisher last contacted on 17/02/2014
• Classification
​ green

## Publications in this journal

• ##### Article: Effects of local high-frequency perturbation on a turbulent boundary layer by synthetic jet injection
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ABSTRACT: An experimental study is performed to investigate the local high-frequency perturbation effects of a synthetic jet injection on a flat-plate turbulent boundary layer. Parameters of the synthetic jet are designed to force a high-frequency perturbation from a thin spanwise slot in the wall. In the test locations downstream of the slot, it is found that skin-friction is reduced by the perturbation, which is languishingly evolved downstream of the slot with corresponding influence on the near-wall regeneration mechanism of turbulent structures. The downstream slot region is divided into two regions due to the influence strength of the movement of spanwise vortices generated by the high-frequency perturbation. Interestingly, the variable interval time average technique is found to be disturbed by the existence of the spanwise vortices’ motion, especially in the region close to the slot. Similar results are obtained from the analysis of the probability density functions of the velocity fluctuation time derivatives, which is another indirect technique for detecting the enhancement or attenuation of streamwise vortices. However, both methods have shown consistent results with the skin-friction reduction mechanism in the far-away slot region. The main purpose of this paper is to remind researchers to be aware of the probable influence of spanwise vortices’ motion in wall-bounded turbulence control.
Fluid Dynamics Research 08/2015; 47(4). DOI:10.1088/0169-5983/47/4/045501
• ##### Article: Experimental study of internal wave generation by convection in water
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ABSTRACT: We experimentally investigate the dynamics of water cooled from below at 0^oC and heated from above. Taking advantage of the unusual property that water's density maximum is at about 4^oC, this set-up allows us to simulate in the laboratory a turbulent convective layer adjacent to a stably stratified layer, which is representative of atmospheric and stellar conditions. High precision temperature and velocity measurements are described, with a special focus on the convectively excited internal waves propagating in the stratified zone. Most of the convective energy is at low frequency, and corresponding waves are localized to the vicinity of the interface. However, we show that some energy radiates far from the interface, carried by shorter horizontal wavelength, higher frequency waves. Our data suggest that the internal wave field is passively excited by the convective fluctuations, and the wave propagation is correctly described by the dissipative linear wave theory.
Fluid Dynamics Research 06/2015; 47(4). DOI:10.1088/0169-5983/47/4/045502
• ##### Article: The boundary layers of an unsteady separated stagnation-point flow of a viscous incompressible fluid over a moving plate
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ABSTRACT: In this paper we have investigated the boundary layer analysis of an unsteady separated stagnation-point (USSP) flow of an incompressible viscous fluid over a flat plate, moving in its own plane with a given speed . The effects of the accelerating parameter a and unsteadiness parameter β on the flow characteristics are explored numerically. Our analysis, based on the similarity solution of the boundary layer equations, indicates that the governing ordinary differential equation, which is non-linear in nature, has either a unique solution, dual solutions or multiple solutions under a negative unsteadiness parameter β with a given value of a. Whatever the number of solutions may be, these solutions are of two types: one is the attached flow solution (AFS) and the other is the reverse flow solution (RFS). A novel result which emerges from our analysis is the relationship between a and β. This relationship essentially gives us the conditions needed for the solutions that exhibit flow separation (where ) and those conditions that exhibit only flow reattachment (where ). Another noteworthy result which arises from the present analysis is the existing number of non-zero stagnation-points inside the flow for the given values of a and β. It is found that this number is exactly two when the velocity gradient at the wall is positive; otherwise this number will only be one. For a stationary plate , this USSP flow is found to be separated for all values of a and β in both cases of AFS and RFS. Finally, we have also established that in the case of AFS flow over a stationary plate, no stagnation-point exists inside the flow, even though the flow becomes separated for all values of a and β.
Fluid Dynamics Research 06/2015; 47(3). DOI:10.1088/0169-5983/47/3/035504
• ##### Article: Effects of surface roughness and electrokinetic heterogeneity on electroosmotic flow in microchannel
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ABSTRACT: In this paper, a hybrid lattice-Boltzmann and finite-difference (LB-FD) model is applied to simulate the effects of three-dimensional surface roughness and electrokinetic heterogeneity on electroosmotic flow (EOF) in a microchannel. The lattice-Boltzmann (LB) method has been employed to obtain the flow field and a finite-difference (FD) method is used to solve the Poisson-Boltzmann (PB) equation for the electrostatic potential distribution. Numerical simulation of flow through a square cross-section microchannel with designed roughness is conducted and the results are critically analysed. The effects of surface heterogeneity on the electroosmotic transport are investigated for different roughness height, width, roughness interval spacing, and roughness surface potential. Numerical simulations reveal that the presence of surface roughness changes the nature of electroosmotic transport through the microchannel. It is found that the electroosmotic velocity decreases with the increase in roughness height and the velocity profile becomes asymmetric. For the same height of the roughness elements, the EOF velocity rises with the increase in roughness width. For the heterogeneously charged rough channel, the velocity profile shows a distinct deviation from the conventional plug-like flow pattern. The simulation results also indicate locally induced flow vortices which can be utilized to enhance the flow and mixing within the microchannel. The present study has important implications towards electrokinetic flow control in the microchannel, and can provide an efficient way to design a microfluidic system of practical interest.
Fluid Dynamics Research 06/2015; 47(3). DOI:10.1088/0169-5983/47/3/035505
• ##### Article: Experimental observation of the collision of three vortex rings
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ABSTRACT: We investigate for the first time the motion, interaction and simultaneous collision between three initially stable vortex rings arranged symmetrically, making an angle of 120 degrees between their straight path lines. We report results with laminar vortex rings in air and water obtained through measurements of the ring velocity field with a hot-wire anemometer, both in free flight and during the entire collision. In the air experiment, our flow visualizations allowed us to identify two main collision stages. A first ring-dominated stage where the rings slowdown progressively, increasing their diameter rapidly, followed by secondary vortex structures resulting after the rings make contact. Local portions of the vortex tubes of opposite circulation are coupled together thus creating local arm-like vortex structures moving radially in outward directions, rapidly dissipating kinetic energy. From a similar water experiment, we provide detailed shadowgraph visualizations of both the ring bubble and the full size collision, showing clearly the final expanding vortex structure. It is accurately resolved that the physical contact between vortex ring tubes gives rise to three symmetric expanding vortex arms but also the vortex reconnection of the top and lower vortex tubes. The central collision zone was found to have the lowest kinetic energy during the entire collision and therefore it can be identified as a safe zone. The preserved collision symmetries leading to the weak kinematic activity in the safe zone is the first step into the development of an intermittent hydrodynamic trap for small and lightweight particles.
Fluid Dynamics Research 06/2015; 47(3). DOI:10.1088/0169-5983/47/3/035513
• ##### Article: Mean zonal flow generated by azimuthal harmonic forcing in a rotating cylinder
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ABSTRACT: In this paper, we study analytically the flow in a rotating container subjected to an azimuthal forcing. We show that this mechanical forcing generates a correction to the solid body rotation called mean zonal flow, similar to the time oscillation of the rotation rate of an axisymmetric container. This axisymmetric correction induced by nonlinear effects in the Ekman layers modifies the solid-body rotation of the fluid in the container. At the leading order, the contribution in the bulk is shown to be an azimuthal flow which scales as the square of the amplitude of the multipolar deformation and is independent of the Ekman number. We also show that the mean zonal flow depends on the symmetry of the angular forcing n and the ratio of the angular rate of the deformation to the angular rate of the cylinder . We found that for an elliptical forcing, n = 2, the rotation rate of the zonal flow does not depend on the radial position. In addition, the angular rate is found to be asymmetric with respect to . These scalings are similar to the time harmonic forcing in a cylinder. The particular case of a tidal forcing is also considered.
Fluid Dynamics Research 06/2015; 47(3). DOI:10.1088/0169-5983/47/3/035506
• ##### Article: On the stability of continuously stratified quasi-geostrophic hetons
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ABSTRACT: In this paper we examine the stability of quasi-geostrophic hetons in a stably, continuously stratified fluid. To this purpose we first determinate numerically equilibrium states. Equilibrium hetons consist of two vortices of equal and opposite strength lying at different depths that are steadily translating without deforming. The situation is studied through a parameter space comprising of the vertical offset between the vortices, their horizontal separation distance and their aspect ratio. The study first shows that the equilibrium vortices are not only strongly deformed in the vertical but that their instability modes are also varying within the height of the structures. The main purpose of the present contribution is to study families of equilibria which stem from the case of two vertically aligned cylindrical vortices. It is however shown that other branches of solutions exist with different properties. The paper concludes that hetons may be sensitive to baroclinic instabilities provided the separation distance between the poles of the hetons is moderate both in the horizontal and in the vertical directions. The hetons become stable and efficient ways to transport properties as far as the poles are distant from one another. The critical separation distance in a non-trivial function of the radius-to-height aspect ratio of the poles.
Fluid Dynamics Research 06/2015; 47(3). DOI:10.1088/0169-5983/47/3/035510
• ##### Article: Investigation of the cavitation fluctuation characteristics in a Venturi injector
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ABSTRACT: The suction flow rate in a Venturi injector increases to a maximum and appears to be unstable when critical cavitation occurs. This study analyzes changes in the cavitation length in high-speed videos of a Venturi injector with critical cavitation to find periodic fluctuations in the cavitation cloud. Pressure fluctuation measurements show a dominant low frequency fluctuation that is almost as large as the oscillation frequency seen visually for the same conditions. The variation of the cavitation numbers and the measured transient outlet pressure show that critical cavitation occurs in the Venturi injector when the peak-to-peak pressure difference is greater than a critical value. Moreover, when the cavitation numbers become very small in the cavitation areas, the peak-to-peak pressures begin to decrease. The relationship between the suction performance and the outlet pressure fluctuations has a significant inflection point which can be used to determine proper working conditions. These experimental statistics provide a pressure range based on the inlet and outlet pressures for which the improvement of suction performance will not substantially change the outlet pressure fluctuations. Both the high-speed photography and the pressure measurement show the periodic oscillations of the cavitation cloud in a Venturi injector and can be used to detect the occurrence of critical cavitation.
Fluid Dynamics Research 04/2015; 47(2). DOI:10.1088/0169-5983/47/2/025506
• ##### Article: New analytical approximations for the liquid rise in a capillary tube
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ABSTRACT: We present the ordinary differential equation (ODE) that governs the motion of a liquid rising in a capillary tube in such a way that we can easily derive the principal analytical approximations given in the literature. From this presentation, the numerical solution of the liquid rise over time could be computed very quickly and easily. Furthermore, we derive other analytical approximations not given in the literature, providing a mathematical justification for the cases in which such approximations are good. Some of the approximations found fit the experimental data better than the analytical approximations given in the literature.
Fluid Dynamics Research 04/2015; 47(2). DOI:10.1088/0169-5983/47/2/025505
• ##### Article: Three-dimensional numerical simulation of a vortex ring impinging on a circular cylinder
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ABSTRACT: A vortex ring impinging on a three-dimensional circular cylinder is studied using large eddy simulation for a Reynolds number &$\operatorname{Re}=4\times {{10}^{4}}$; based on the initial translational speed and diameter of the vortex ring. We have investigated the evolution of vortical structures and identified three typical evolution phases. When the primary vortex approaches the cylinder closely, a secondary vortex is generated and its segment parts move inward to the primary vortex ring. Then two large-scale loop-like vortices are formed, which evolve in opposite directions. Thirdly, the two loop-like vortices collide with each other, forming complicated small-scale vortical structures. Moreover, a series of hairpin vortices are generated due to the deformation and stretching of the tertiary vortex. The trajectories of the primary and secondary vortices and the relevant speeds of evolution are discussed. The total kinetic energy and enstrophy are investigated with the purpose of revealing the properties that are relevant to the three evolution phases. The boundary vorticity flux is further studied with the aim of analyzing the generation of vorticity and the connection with the pressure gradient on the cylinder surface.
Fluid Dynamics Research 04/2015; 47(2). DOI:10.1088/0169-5983/47/2/025507