ORCID Profile
0000-0002-0998-2712
Current Organisation
Swinburne University of Technology
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Turbulent Flows | Interdisciplinary Engineering | Ocean Engineering | Fluidisation and Fluid Mechanics
ANZSRC Socio-Economic Objective (SEO)
Effects of Climate Change and Variability on Antarctic and Sub-Antarctic Environments (excl. Social Impacts) | Climate Change Models | Global Effects of Climate Change and Variability (excl. Australia, New Zealand, Antarctica and the South Pacific) (excl. Social Impacts) |
Related Links
Publications
Intermittent flow regimes near the convection threshold in ferromagnetic nanofluids
Publisher: American Physical Society (APS)
Date: 20-01-2015
Magnetic flux density distribution in axial flux machine cores
Publisher: Institution of Engineering and Technology (IET)
Date: 2005
Stability of non-Boussinesq convection via the complex Ginzburg–Landau model
Publisher: IOP Publishing
Date: 09-2004
Acoustic frequency combs using gas bubble cluster oscillations in liquids: a proof of concept
Publisher: Springer Science and Business Media LLC
Date: 08-01-2021
DOI: 10.1038/S41598-020-79567-6
Abstract: We propose a new approach to the generation of acoustic frequency combs (AFC)—signals with spectra containing equidistant coherent peaks. AFCs are essential for a number of sensing and measurement applications, where the established technology of optical frequency combs suffers from fundamental physical limitations. Our proof-of-principle experiments demonstrate that nonlinear oscillations of a gas bubble cluster in water insonated by a low-pressure single-frequency ultrasound wave produce signals with spectra consisting of equally spaced peaks originating from the interaction of the driving ultrasound wave with the response of the bubble cluster at its natural frequency. The so-generated AFC posses essential characteristics of optical frequency combs and thus, similar to their optical counterparts, can be used to measure various physical, chemical and biological quantities.
Complex behaviour of a nanofluid near thermal convection onset: Its nature and features
Publisher: Elsevier BV
Date: 2017
Revisiting plane Couette–Poiseuille flows of a piezo-viscous fluid
Publisher: Elsevier BV
Date: 10-2008
Thermomagnetic convective flows in a vertical layer of ferrocolloid: Perturbation energy analysis and experimental study
Publisher: American Physical Society (APS)
Date: 05-07-2012
Nonlinear stability of mixed convection flow under non-Boussinesq conditions. Part 1. Analysis and bifurcations
Publisher: Cambridge University Press (CUP)
Date: 10-11-1999
DOI: 10.1017/S0022112099006217
Abstract: The weakly nonlinear theory for modelling flows away from the bifurcation point developed by the authors in their previous work (Suslov & Paolucci 1997) is generalized for flows of variable-density fluids in open systems. It is shown that special treatment of the continuity equation is necessary to perform the analysis of such flows and to account for the potential total fluid mass variation in the domain. The stability analysis of non-Boussinesq mixed convection flow of air in a vertical channel is then performed for a wide range of temperature differences between the walls, and Grashof and Reynolds numbers. A cubic Landau equation, which governs the evolution of a disturbance litude, is derived and used to identify regions of subcritical and supercritical bifurcations to periodic flows. Equilibrium disturbance litudes are computed for regions of supercritical bifurcations.
Instability of swirling electrolyte flows driven electromagnetically
Publisher: University of Latvia
Date: 09-2020
Numerical modelling of axisymmetric electromagnetically driven flows in thin layers
Publisher: Australian Mathematical Publishing Association, Inc.
Date: 04-09-2017
Thermomagnetic convection in a vertical layer of ferromagnetic fluid
Publisher: AIP Publishing
Date: 08-2008
DOI: 10.1063/1.2952596
Abstract: Linear stability of convection flow of ferromagnetic fluid between two vertical differentially heated plates placed in a uniform external magnetic field perpendicular to the plates is studied. Complete stability diagrams for two- and three-dimensional disturbances are presented. It is shown that two distinct mechanisms, thermogravitational and magnetic, are responsible for the appearance of three instability modes. The physical nature of all three modes is investigated in detail and the most prominent features are identified to provide guidance for future experimental investigation. Depending on the governing parameters, the instability patterns are shown to consist of vertical stationary magnetoconvection rolls and/or vertically or obliquely counterpropagating thermogravitational or thermomagnetic waves.
Detection and analysis of coherent groups in three-dimensional fully-nonlinear potential wave fields
Publisher: Elsevier BV
Date: 07-2016
Analysis of instability patterns in non-Boussinesq mixed convection using a direct numerical evaluation of disturbance integrals
Publisher: Elsevier BV
Date: 03-2009
UV-plasmonic germicidal radiation beams enabled by sonoluminescence of air bubbles near liquid-metal particles
Publisher: SPIE
Date: 30-12-2019
DOI: 10.1117/12.2541086
Acoustic, Phononic, Brillouin Light Scattering and Faraday Wave-Based Frequency Combs: Physical Foundations and Applications
Publisher: MDPI AG
Date: 22-05-2022
DOI: 10.3390/S22103921
Abstract: Frequency combs (FCs)—spectra containing equidistant coherent peaks—have enabled researchers and engineers to measure the frequencies of complex signals with high precision, thereby revolutionising the areas of sensing, metrology and communications and also benefiting the fundamental science. Although mostly optical FCs have found widespread applications thus far, in general FCs can be generated using waves other than light. Here, we review and summarise recent achievements in the emergent field of acoustic frequency combs (AFCs), including phononic FCs and relevant acousto-optical, Brillouin light scattering and Faraday wave-based techniques that have enabled the development of phonon lasers, quantum computers and advanced vibration sensors. In particular, our discussion is centred around potential applications of AFCs in precision measurements in various physical, chemical and biological systems in conditions where using light, and hence optical FCs, faces technical and fundamental limitations, which is, for ex le, the case in underwater distance measurements and biomedical imaging applications. This review article will also be of interest to readers seeking a discussion of specific theoretical aspects of different classes of AFCs. To that end, we support the mainstream discussion by the results of our original analysis and numerical simulations that can be used to design the spectra of AFCs generated using oscillations of gas bubbles in liquids, vibrations of liquid drops and plasmonic enhancement of Brillouin light scattering in metal nanostructures. We also discuss the application of non-toxic room-temperature liquid–metal alloys in the field of AFC generation.
Neural echo state network using oscillations of gas bubbles in water
Publisher: American Physical Society (APS)
Date: 13-04-2022
Stability of mixed-convection flow in a tall vertical channel under non-boussinesq conditions
Publisher: Cambridge University Press (CUP)
Date: 10-11-1995
DOI: 10.1017/S0022112095004022
Abstract: We have examined the linear stability of the fully developed mixed-convection flow in a differentially heated tall vertical channel under non-Boussinesq conditions. The Three-dimensional analysis of the stability problem was reduced to an equivalent two-dimensional one by the use of Squire's transformation. The resulting eigenvalue problem was solved using an integral Chebyshev pseudo-spectral method. Although Squire's theorem cannot be proved analytically, two-dimensional disturbances are found to be the most unstable in all cases. The influence of the non-Boussinesq effects on the stability was studied. We have investigated the dependence of the critical Grashof and Reynolds numbers on the temperature difference. The results show that four different modes of instability are possible, two of which are new and due entirely to non-Boussinesq effects.
Spiking dynamics of frequency upconverted field generated in continuous-wave excited rubidium vapors
Publisher: Optica Publishing Group
Date: 29-07-2020
DOI: 10.1364/JOSAB.395087
Abstract: We report on spiking dynamics of frequency upconverted emission at 420 nm generated on the 6 P 3 / 2 − 5 S 1 / 2 transition in Rb vapor two-photon excited to the 5 D 5 / 2 level with laser light at 780 and 776 nm. The spike duration is shorter than the natural lifetime of any excited level involved in the interaction with both continuous and pulsed pump radiation. The spikes at 420 nm are attributed to temporal properties of the directional emission at 5.23 µm generated on the population-inverted 5 D 5 / 2 − 6 P 3 / 2 transition. A link between the spiking regime and cooperative effects is discussed. We suggest that the observed stochastic behavior is due to the quantum-mechanical nature of the cooperative effects rather than random fluctuation of the applied laser fields.
Statistics of Wave Orbital Velocity in Deep Water Random Directional Wave Fields
Publisher: American Society of Mechanical Engineers
Date: 07-2012
Abstract: A direct numerical simulation method is used to monitor the evolution of nonlinear random directional wave fields. The aim is to investigate the combined effect of high order nonlinearity and directional energy distribution on the statistics of wave orbital velocity. Results show that the development of modulational wave instability and the concurrent formation of large litude waves lead to a substantial departure of the statistics of the horizontal velocity from the Normal (or Gaussian) probability density function when the wave field is long crested. As short crestedness increases, departure from the Normal distribution gradually diminishes and eventually vanishes for sufficiently broad directional spreading.
E–ε Model of Spray-Laden Near-Sea Atmospheric Layer in High Wind Conditions
Publisher: American Meteorological Society
Date: 02-2014
Abstract: In-depth understanding and accurate modeling of the interaction between ocean spray and a turbulent flow under high wind conditions is essential for improving the intensity forecasts of hurricanes and severe storms. Here, the authors consider the E–ε closure for a turbulent flow model that accounts for the effects of the variation of turbulent energy and turbulent mixing length caused by spray stratification. The obtained analytical and numerical solutions show significant differences between the current E–ε model and the lower-order turbulent kinetic energy (TKE) model considered previously. It is shown that the reduction of turbulent energy and mixing length above the wave crest level, where the spray droplets are generated, that is not accounted for by the TKE model results in a significant suppression of turbulent mixing in this near-wave layer. In turn, suppression of turbulence causes an acceleration of flow and a reduction of the drag coefficient that is qualitatively consistent with field observations if spray is fine (even if its concentration is low) or if droplets are large but their concentration is sufficiently high. In the latter case, spray inertia may become important. This effect is subsequently examined. It is shown that spray inertia leads to the reduction of wind velocity in the close proximity of the wave surface relative to the reference logarithmic profile. However, at higher altitudes the suppression of flow turbulence by the spray still results in the wind acceleration and the reduction of the local drag coefficient.
Searching convective/absolute instability boundary for flows with fully numerical dispersion relation
Publisher: Elsevier BV
Date: 12-2001
Electromagnetically driven flow of electrolyte in a thin annular layer: axisymmetric solutions
Publisher: Cambridge University Press (CUP)
Date: 05-09-2017
DOI: 10.1017/JFM.2017.551
Abstract: Experimental observations of an azimuthal electrolyte flow driven by Lorentz force in a thin annular fluid layer placed on top of a magnet show that it develops a robust vortical system near the outer cylindrical wall. It appears to be a result of instabilities developing on a background of steady axisymmetric flow. Therefore, the goal of this paper is to establish a scene for a future comprehensive stability analysis of such a flow. We discuss popular depth-averaged and quasi-two-dimensional approximate solutions that take advantage of the thin-layer assumption first, and argue that they cannot lead to the observed flow patterns. Thus, three-dimensional toroidal flows are considered. Their similarities to various other well-studied rotating flow configurations are outlined, but no close match is found. Multiple axisymmetric solutions are detected numerically for the same governing parameters, indicating the possibility of subcritical bifurcations, namely type 1, consisting of a single torus, and type 2, developing a second counter-rotating toroidal flow near the outer cylinder. It is suggested that the transition between these two axisymmetric solutions is likely to be caused by the centrifugal instability, while the shear-type instability of the type 2 solution may be responsible for the observed vortex structures. However, a dedicated stability analysis which is currently underway and will be reported in a separate publication is required to confirm these hypotheses.
Arithmetic with optical topological charges in stepwise-excited Rb vapor
Publisher: The Optical Society
Date: 08-03-2016
DOI: 10.1364/OL.41.001146
Effect of Evaporating Sea Spray on Heat Fluxes in a Marine Atmospheric Boundary Layer
Publisher: American Meteorological Society
Date: 07-2019
Abstract: A detailed analysis of the evaporating ocean spray effect on the vertical latent and sensible heat fluxes in a marine atmospheric boundary layer (MABL) for different droplet sizes, vertical distributions of air temperature, humidity, and turbulent intensity is presented. For our analysis we have employed a two-temperature nonequilibrium MABL model developed in our previous work. The obtained analytical and numerical solutions show that the latent and total heat fluxes are significantly enhanced by large droplets because these droplets produce steep vertical gradients of moisture and air temperature in a MABL. Small droplets, however, do not noticeably change the total heat flux but rather redistribute the energy between its sensible and latent components. It has been shown that evaporating spray affects the turbulent kinetic energy (thus the intensity of the vertical turbulent transport) mostly mechanically by altering the vertical distribution of the mass density of the air–spray mixture rather than thermodynamically by changing vertical profiles of the air temperature and moisture. Furthermore, we have found that the vertical profiles of heat fluxes are approximately self-similar for a wide range of defining parameters, that is, can be approximately scaled to a reference heat profile for a wide range of vertical distributions of the temperature, humidity, and turbulence intensity. The obtained analytical expressions for the vertical heat fluxes affected by the spray presence enable their quick and efficient calculations. This will allow for the future construction of a computationally efficient spray and accurate parameterization to be used in global weather prediction models.
Nonlinear stability of mixed convection flow under non-Boussinesq conditions. Part 2. Mean flow characteristics
Publisher: Cambridge University Press (CUP)
Date: 10-11-1999
DOI: 10.1017/S0022112099006229
Abstract: Based on litude expansions developed in Part 1 (Suslov & Paolucci 1999), we examine the mean flow characteristics of non-Boussinesq mixed convection flow of air in a vertical channel in the vicinity of bifurcation points for a wide range of temperature differences between the walls, and Grashof and Reynolds numbers. The constant mass flux and constant pressure gradient formulations are shown to lead to qualitatively similar, but quantitatively different, results. The physical nature of the distinct shear and buoyancy disturbances is investigated, and detailed mean flow and energy analyses are presented. The variation of the total mass of fluid in a flow domain as disturbances develop is discussed. The average Nusselt number and mass flux are estimated for supercritical regimes for a wide range of governing parameters.
Modeling of Sample Dynamics in Rectangular Asymmetrical Flow Field-Flow Fractionation Channels
Publisher: American Chemical Society (ACS)
Date: 12-08-2000
DOI: 10.1021/AC9915022
Abstract: We model the evolution of the concentration field of macromolecules in a rectangular asymmetrical flow field-flow fractionation channel using center manifold techniques. The deviation of the primary flow from a parabolic profile influences the concentration field and this is investigated to complement previously known results. The long-term evolution of the components of the s le is shown to be well described by a one-dimensional advection-diffusion equation. The coefficients of this equation are determined by the rigorous analysis of the complete set of equations governing the two-dimensional fluid flow. This model gives quantitative predictions of the elution time of the s les, the width of the concentration pulse, and the resolution of the apparatus. The influence of initial s le width and effects of the secondary relaxation from focusing to elution conditions are discussed. Reported theoretical predictions are in agreement with experimental results published previously.
Biomechanical Sensing Using Gas Bubbles Oscillations in Liquids and Adjacent Technologies: Theory and Practical Applications
Publisher: MDPI AG
Date: 10-08-2022
DOI: 10.3390/BIOS12080624
Abstract: Gas bubbles present in liquids underpin many natural phenomena and human-developed technologies that improve the quality of life. Since all living organisms are predominantly made of water, they may also contain bubbles—introduced both naturally and artificially—that can serve as biomechanical sensors operating in hard-to-reach places inside a living body and emitting signals that can be detected by common equipment used in ultrasound and photoacoustic imaging procedures. This kind of biosensor is the focus of the present article, where we critically review the emergent sensing technologies based on acoustically driven oscillations of bubbles in liquids and bodily fluids. This review is intended for a broad biosensing community and transdisciplinary researchers translating novel ideas from theory to experiment and then to practice. To this end, all discussions in this review are written in a language that is accessible to non-experts in specific fields of acoustics, fluid dynamics and acousto-optics.
Oscillatory instability of convection in ferromagnetic nanofluid and in transformer oil
Publisher: IOP Publishing
Date: 07-11-2016
The use of ferrofluids for heat removal: Advantage or disadvantage?
Publisher: Elsevier BV
Date: 06-2017
Magneto-gravitational convection in a vertical layer of ferrofluid in a uniform oblique magnetic field
Publisher: Cambridge University Press (CUP)
Date: 22-04-2016
DOI: 10.1017/JFM.2016.231
Abstract: The stability of base gravitational convection in a layer of ferrofluid confined between two vertical wide and tall non-magnetic plates, heated from one side, cooled from the other and placed in a uniform oblique external magnetic field is studied. Two distinct mechanisms, thermo-gravitational and thermo-magnetic, are found to be responsible for the appearance of various stationary and wave-like instability modes. The characteristics of all instability modes are investigated as functions of the orientation angles of the applied magnetic field and its magnitude for various values of magnetic parameters when both the thermo-magnetic and gravitational buoyancy mechanisms are active. The original three-dimensional problem is cast in an equivalent two-dimensional form using generalised Squire’s transformations, which significantly reduces a computational cost. Subsequently, full three-dimensional instability patterns are recovered using the inverse Squire’s transformation, and the optimal field and pattern orientations are determined.
Linear stability and saddle-node bifurcation of electromagnetically driven electrolyte flow in an annular layer
Publisher: Cambridge University Press (CUP)
Date: 28-01-2020
DOI: 10.1017/JFM.2020.29
Amplified spontaneous emission at 523 μm in two-photon excited rubidium vapor
Publisher: The Optical Society
Date: 08-11-2017
Thermomagnetic instabilities in a vertical layer of ferrofluid: nonlinear analysis away from a critical point
Publisher: IOP Publishing
Date: 07-11-2016
Beamed UV sonoluminescence by aspherical air bubble collapse near liquid-metal microparticles
Publisher: Springer Science and Business Media LLC
Date: 30-01-2020
DOI: 10.1038/S41598-020-58185-2
Abstract: Irradiation with UV-C band ultraviolet light is one of the most commonly used ways of disinfecting water contaminated by pathogens such as bacteria and viruses. Sonoluminescence, the emission of light from acoustically-induced collapse of air bubbles in water, is an efficient means of generating UV-C light. However, because a spherical bubble collapsing in the bulk of water creates isotropic radiation, the generated UV-C light fluence is insufficient for disinfection. Here we show, based on detailed theoretical modelling and rigorous simulations, that it should be possible to create a UV light beam from aspherical air bubble collapse near a gallium-based liquid-metal microparticle. The beam is perpendicular to the metal surface and is caused by the interaction of sonoluminescence light with UV plasmon modes of the metal. We estimate that such beams can generate fluences exceeding 10 mJ/cm 2 , which is sufficient to irreversibly inactivate most common pathogens in water with the turbidity of more than 5 Nephelometric Turbidity Units.
Convective and absolute instabilities in non-Boussinesq mixed convection
Publisher: Springer Science and Business Media LLC
Date: 04-05-2007
Nonlinear dynamic behavior of microscopic bubbles near a rigid wall
Publisher: American Physical Society (APS)
Date: 12-06-2012
Stability of plane Poiseuille–Couette flows of a piezo-viscous fluid
Publisher: Elsevier BV
Date: 02-2009
Spectrally wide acoustic frequency combs generated using oscillations of polydisperse gas bubble clusters in liquids
Publisher: American Physical Society (APS)
Date: 08-09-2021
Thermomagnetic convection in a layer of ferrofluid placed in a uniform oblique external magnetic field
Publisher: Cambridge University Press (CUP)
Date: 05-01-2015
DOI: 10.1017/JFM.2014.709
Abstract: Linear stability of magnetoconvection of a ferromagnetic fluid contained between two infinite differentially heated non-magnetic plates in the presence of an oblique uniform external magnetic field is studied in zero gravity conditions. The thermomagnetic convection that arises is caused by the spatial variation of magnetisation occurring due to its dependence on the temperature. The critical values of the governing parameters at which the transition between motionless and convective states is observed are determined for various field inclination angles and for fluid magnetic parameters that are consistently chosen from a realistic experimental range. It is shown that, similar to natural paramagnetic fluids, the most prominent convection patterns align with the in-layer component of the applied magnetic field but in contrast to such paramagnetic fluids the instability patterns detected in ferrofluids can be oscillatory. It is also found that, contrary to paramagnetic fluids, the stability characteristics of magnetoconvection in ferrofluids depend on the magnitude of the applied field which becomes an additional parameter of the problem. This is shown to be due to the nonlinearity of the magnetic field distribution within the ferrofluid.
Acoustic, Phononic, Brillouin Light Scattering and Faraday Wave Based Frequency Combs: Physical Foundations and Applications
Publisher: MDPI AG
Date: 04-05-2022
DOI: 10.20944/PREPRINTS202205.0003.V1
Abstract: Frequency combs (FCs)& mdash spectra containing equidistant coherent peaks& mdash have enabled researchers and engineers to measure the frequencies of complex signals with high precision thereby revolutionising the areas of sensing, metrology and communications and also benefiting the fundamental science. Although mostly optical FCs have found widespread applications thus far, in general FCs can be generated using waves other than light. Here, we review and summarise recent achievements in the emergent field of acoustic frequency combs (AFCs) including phononic FCs and relevant acousto-optical, Brillouin light scattering and Faraday wave-based techniques that have enabled the development of phonon lasers, quantum computers and advanced vibration sensors. In particular, our discussion is centred around potential applications of AFCs in precision measurements in various physical, chemical and biological systems in conditions, where using light, and hence optical FCs, faces technical and fundamental limitations, which is, for ex le, the case in underwater distance measurements and biomedical imaging applications. This review article will also be of interest to readers seeking a discussion of specific theoretical aspects of different classes of AFCs. To that end, we support the mainstream discussion by the results of our original analysis and numerical simulations that can be used to design the spectra of AFCs generated using oscillations of gas bubbles in liquids, vibrations of liquid drops and plasmonic enhancement of Brillouin light scattering in metal nanostructures. We also discuss the application of non-toxic room-temperature liquid-metal alloys in the field of AFC generation.
Nonlinear interaction of thermogravitational waves and thermomagnetic rolls in a vertical layer of ferrofluid placed in a normal magnetic field
Publisher: AIP Publishing
Date: 2019
DOI: 10.1063/1.5070092
Abstract: The interacting thermogravitational and thermomagnetic instabilities arising in a vertical layer of non-isothermal ferrofluid placed in a horizontal magnetic field are investigated by means of a weakly nonlinear analysis. An expansion in disturbance litude leads to the reduction of a full problem to a system of coupled cubic Landau litude equations. Their solutions are analyzed and interpreted from a physical point of view. The details of an intricate competition between gravitational and magnetic buoyancy mechanisms are highlighted. The spatial structure of the resulting flow patterns is discussed. It is shown that the parametric existence regions determined for finite litude disturbances differ drastically from those predicted based on the analysis of infinitesimal perturbations. Subsequently, the cross-layer heat flux characteristics are discussed. It is shown that the co-existence of two physical mechanisms of convection can lead to a suppression of heat transfer rather than to its enhancement.
Numerical aspects of searching convective/absolute instability transition
Publisher: Elsevier BV
Date: 02-2006
The mechanism of vortex instability in electromagnetically driven flow in an annular thin layer of electrolyte
Publisher: Australian Mathematical Publishing Association, Inc.
Date: 20-08-2020
DOI: 10.21914/ANZIAMJ.V61I0.15168
Abstract: A circumferential flow of a conducting fluid in an annular channel can be created by the action of a Lorentz force arising as a result of the interaction between an applied vertical magnetic field and a radial electric current flowing through the electrolyte. Quite unexpectedly, experiments revealed that a robust vortex system appears near the outer cylindrical wall in such flows. McCloughan and Suslov (J. Fluid Mech. 887:A23, 2020) (McCS) reported comprehensive linear stability results of such a flow for variable Lorentz forcing. Here we complement that study by investigating the flow structure as a function of the channel aspect ratio. Remarkably, despite the completely different physical nature of parametric dependences, dynamic in McCS and purely geometric here, we show that in both scenarios vortices appear on a background of a steady axisymmetric flow at the boundary between two counter-rotating toroidal structures and have a similar energy distributions. The two studies demonstrate the robustness of the mechanism responsible for the vortex formation: Rayleigh's inviscid centrifugal instability aided by radial shear in the boundary layer near the outer cylindrical wall. References P. A. Davidson. An introduction to magnetohydrodynamics. Cambridge University Press, 2nd edition, 2017. doi:10.1017/CBO9780511626333. J. McCloughan and S. A. Suslov. Linear stability and saddle–node bifurcation of electromagnetically driven electrolyte flow in an annular layer. J. Fluid Mech., 887:A23.1–30, 2020. doi:10.1017/jfm.2020.29. J. Perez-Barrera, J. E. Perez-Espinoza, A. Ortiz, E. Ramos, and S. Cuevas. Instability of electrolyte flow driven by an azimuthal Lorentz force. Magnetohydrodynamics, 51(2):203–213, 2015. mhd.sal.lv/contents/2015/2/MG.51.2.4.R.html. S. A. Suslov, J. Perez-Barrera, and S. Cuevas. Electromagnetically driven flow of electrolyte in a thin annular layer: Axisymmetric solutions. J. Fluid Mech., 828: 573–600, 2017. doi:10.1017/jfm.2017.551.
Effects of coupling, bubble size, and spatial arrangement on chaotic dynamics of microbubble cluster in ultrasonic fields
Publisher: Acoustical Society of America (ASA)
Date: 11-2013
DOI: 10.1121/1.4821202
Abstract: Microbubble clustering may occur when bubbles become bound to targeted surfaces or are grouped by acoustic radiation forces in medical diagnostic applications. The ability to identify the formation of such clusters from the ultrasound echoes may be of practical use. Nonlinear numerical simulations were performed on clusters of microbubbles modeled by the modified Keller-Miksis equations. Encapsulated bubbles were considered to mimic practical applications but the aim of the study was to examine the effects of inter-bubble spacing and bubble size on the dynamical behavior of the cluster and to see if chaotic or bifurcation characteristics could be helpful in diagnostics. It was found that as microbubbles were clustered closer together, their oscillation litude for a given applied ultrasound power was reduced, and for inter-bubble spacing smaller than about ten bubble radii nonlinear subharmonics and ultraharmonics were eliminated. For clustered microbubbles, as for isolated microbubbles, an increase in the applied acoustic power caused bifurcations and transition to chaos. The bifurcations preceding chaotic behavior were identified by Floquet analysis and confirmed to be of the period-doubling type. It was found that as the number of microbubbles in a cluster increased, regularization occurred at lower ultrasound power and more windows of order appeared.
Two-Temperature Nonequilibrium Model of a Marine Boundary Layer Laden with Evaporating Ocean Spray under High-Wind Conditions
Publisher: American Meteorological Society
Date: 10-2016
Abstract: A nonequilibrium two-temperature multiphase model of the atmospheric boundary layer above wave crests that is laden with evaporating ocean spray in high-wind condition is presented. The governing equations are derived from basic physical principles of conservation of momentum, mass, and thermal energy in multiphase flows. The model derivation uses an Eulerian multifluid approach that considers spray as a continuous medium interacting with the gas phase. The E − ε turbulence closure is used. The developed theoretical framework accounts for the nonuniform ocean spray distribution and the thermal energy exchange between air and spray droplets that, in general, have different temperatures above the wave crest level. Such thermodynamic nonequilibrium conditions are shown to exist when the spray concentration is relatively low and the air humidity is far from saturation. The mechanical and thermodynamic effects of the evaporating spray on airflow and heat transport characteristics are obtained and shown to depend sensitively on the spray concentration.
Biomechanical Sensing using Gas Bubbles Oscillations in Liquids and Adjacent Technologies: Theory and Practical Applications
Publisher: MDPI AG
Date: 07-07-2022
DOI: 10.20944/PREPRINTS202207.0112.V1
Abstract: Gas bubbles present in liquids underpin many natural phenomena and human-developed technologies that improve the quality of life. Since all living organisms are predominantly made of water, they may also contain gas bubbles& mdash introduced both naturally and artificially& mdash that can serve as biomechanical sensors operating in hard-to-reach places inside a living body and emitting signals that can be detected by common equipment used in ultrasound and photoacoustic imaging procedures. This kind of biosensors is the focus of the present article, where we critically review the emergent sensing technologies based on acoustically driven oscillations of gas bubbles in liquids and bodily fluids. This review is intended for a broad biosensing community and transdisciplinary researchers translating novel ideas from theory to experiment and then to practice. To this end, all discussions in this review are written in a language that is accessible to non-experts in specific fields of acoustics, fluid dynamics and acousto-optics.
The influence of uniform external magnetic field on heat transfer in ferrofluids
Publisher: University of Latvia
Date: 06-2018
Intermittent dynamic bursting in vertically vibrated liquid drops
Publisher: AIP Publishing
Date: 12-2020
DOI: 10.1063/5.0031593
Abstract: A previously unreported regime of type III intermittency is observed in a vertically vibrated milliliter-sized liquid drop submerged in a more viscous and less dense immiscible fluid layer supported by a hydrophobic solid plate. As the vibration litude is gradually increased, subharmonic Faraday waves are excited at the upper surface of the drop. We find a narrow window of vibration litudes slightly above the Faraday threshold, where the drop exhibits an irregular sequence of large litude bursting events alternating with intervals of low litude activity. Our experimental results and the suggested phenomenological model directly link the onset of the intermittent bursting regime in an isolated liquid drop to the competition between two hydrodynamic modes: the surface Faraday waves and the shape deformation mode, responsible for the horizontal drop elongation.
Two-equation model of mean flow resonances in subcritical flow systems
Publisher: American Institute of Mathematical Sciences (AIMS)
Date: 2008
Analysis of coupling between hydrodynamic and thermal instabilities in non-Boussinesq convection
Publisher: Elsevier BV
Date: 11-2005
Advection-dispersion in symmetric field-flow fractionation channels
Publisher: Springer Science and Business Media LLC
Date: 1999
Nonlinear analysis of convection flow in a tall vertical enclosure under non-Boussinesq conditions
Publisher: Cambridge University Press (CUP)
Date: 10-08-1997
DOI: 10.1017/S0022112097005971
Abstract: A weakly nonlinear theory, based on the combined litude–multiple timescale expansion, is developed for the flow of an arbitrary fluid governed by the low-Mach-number equations. The approach is shown to be different from the one conventionally used for Boussinesq flows. The range of validity of the applied analysis is discussed and shown to be sufficiently large. Results are presented for the natural convection flow of air inside a closed differentially heated tall vertical cavity for a range of temperature differences far beyond the region of validity of the Boussinesq approximation. The issue of possible resonances of two different types is noted. The character of bifurcations for the shear- and buoyancy-driven instabilities and their interaction is investigated in detail. Lastly, the energy transfer mechanisms are analysed in supercritical regimes.
Interaction of gravitational and magnetic mechanisms of convection in a vertical layer of a magnetic fluid
Publisher: Elsevier BV
Date: 2010
A Petrov–Galerkin method for flows in cavities: enclosure of aspect ratio 8
Publisher: Wiley
Date: 28-10-2002
DOI: 10.1002/FLD.386
Stability of natural convection flow in a tall vertical enclosure under non-Boussinesq conditions
Publisher: Elsevier BV
Date: 08-1995
On the definition of Landau constants in amplitude equations away from a critical point
Publisher: The Royal Society
Date: 11-2018
DOI: 10.1098/RSOS.180746
Abstract: A weakly nonlinear stability analysis of shear flows based on litude expansion is re-examined. While it has been known that the condition required to define the coefficients of the resulting Stuart–Landau series representing the nonlinear temporal evolution of the most lified Fourier component of a disturbance is not unique, we show that it can be formulated in a flexible generic form that incorporates different conditions used by various authors previously. The new formulation is interpreted from the point of view of low-dimensional projection of a full solution of a problem onto the space spanned by the basic flow vector and the eigenvector of the linearized problem. It is rigorously proven that the generalized condition formulated in this work reduces to a standard solvability condition at the critical point, where the basic flow first becomes unstable with respect to infinitesimal disturbances, and that it results in a well-posed problem for the determination of coefficients of Stuart–Landau series both at the critical point and a finite distance away from it. On a practical side, the generalized condition reported here enables one to choose the projection in such a way that the resulting low-dimensional approximate solution emphasizes specific physical features of interest via selecting the appropriate projection weight matrix without changing the overall asymptotic expansion procedure.
Mechanism of nonlinear flow pattern selection in moderately non-Boussinesq mixed convection
Publisher: American Physical Society (APS)
Date: 02-2010
Effect of Ocean Spray on Vertical Momentum Transport Under High-Wind Conditions
Publisher: Springer Science and Business Media LLC
Date: 17-06-2011
Related Organisations
Moscow Institute Of Physics And Technology
Location: Russian Federation
Related Funding Activities
Linkage Infrastructure, Equipment And Facilities - Grant ID: LE140100079
Start Date: 2014
End Date: 12-2016
Amount: $200,000.00
Funder: Australian Research Council
View Funded Activity