Temporal instability characteristics of Rayleigh–Taylor and Kelvin–Helmholtz mechanisms of an inviscid cylindrical interface

Vadivukkarasan, M.

doi:10.1007/s11012-020-01275-2

Cited by 8 publications

(4 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As the research progresses, the problem being studied and the models being used are becoming more and more practical and complex [8][9][10][11][12][13][14][15][16][17][18][19][20][21]. In recent years, the results in statistical physics perspectives obtained with the help of Discrete Boltzmann Method (DBM) and complex physical field analysis techniques have also provided a range of new insights into the study of hydrodynamic instabilities.…”

Section: Introductionmentioning

confidence: 99%

Discrete Boltzmann modeling of Rayleigh-Taylor instability: effects of interfacial tension, viscosity and heat conductivity

Chen,

Xu,

Chen

et al. 2022

Preprint

View full text Add to dashboard Cite

The Rayleigh-Taylor Instability (RTI) in compressible flow with inter-molecular interactions is probed via the Discrete Boltzmann Method (DBM). The effects of interfacial tension, viscosity and heat conduction are investigated. It is found that the influences of interfacial tension on the perturbation amplitude, bubble velocity, and two kinds of entropy production rates all show differences at different stages of RTI evolution. It inhibits the RTI evolution at the bubble acceleration stage, while at the asymptotic velocity stage, it first promotes and then inhibits the RTI evolution.Viscosity and heat conduction inhibit the RTI evolution. Viscosity shows a suppressive effect on entropy generation rate related to heat flow at the early stage but a first promotive and then suppressive effect on entropy generation rate related to heat flow at a later stage. Heat conduction shows a promotive effect on entropy generation rate related to heat flow at an early stage. Still, it offers a first promotive and then suppressive effect on entropy generation rate related to heat flow at a later stage. By introducing the morphological boundary length, we found that the stage of exponential growth of interface length with time corresponds to the bubble acceleration stage. The first maximum point of interface length change rate and the first maximum point of the change rate of entropy generation rate related to viscous stress can be used as a new criterion for RTI to enter the asymptotic velocity stage.

show abstract

Section: Introductionmentioning

confidence: 99%

Discrete Boltzmann modeling of Rayleigh-Taylor instability: effects of interfacial tension, viscosity and heat conductivity

Chen,

Xu,

Chen

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

“…A complete understanding of the relation between the RTI and the KHI is important in understanding the hydrodynamic instability-driven mixing processes. In addition to the growth rate and final state, some studies have been made on the early linear and early nonlinear evolution of the coupled instability [39][40][41][42][43][44][45][46][47][48][49] . Both the instability modes and devolution processes that may be manifested when two such mechanisms occur simultaneously are of current interest.…”

Section: Introductionmentioning

confidence: 99%

“…Akula et al 43 showed that the superposition of shear on RTI at small Atwood number increases the mixing width and growth rate at early times. Vadivukkarasan et al [44][45][46] described the 3D destabilization characteristics of cylindrical and annular interfaces under the combined RTKHI, and the effects of various parameters on the most unstable wavenumbers were studied. Sarychev et al 47 found that an undulating topography on the interface coating/base material is resulted from the coupled RTKHI.…”

Section: Introductionmentioning

confidence: 99%

Effects of the initial perturbations on the Rayleigh-Taylor-Kelvin-Helmholtz instability system

Chen,

Xu,

Zhang

et al. 2021

Preprint

View full text Add to dashboard Cite

In the paper, the effects of initial perturbations on the Rayleigh-Taylor instability (RTI), Kelvin-Helmholtz instability (KHI), and the coupled Rayleigh-Taylor-Kelvin-Helmholtz instability (RTKHI) systems are investigated using a multiple-relaxation-time discrete Boltzmann model. Six different perturbation interfaces are designed to study the effects of the initial perturbations on the instability systems. It is found that the initial perturbation has a significant influence on the evolution of RTI. The sharper the interface, the faster the growth of bubble or spike. While the influence of initial interface shape on KHI evolution can be ignored. Based on the mean heat flux strength D 3,1 , the effects of initial interfaces on the coupled RTKHI are examined in detail. The research is focused on two aspects: (i) the main mechanism in the early stage of the RTKHI, (ii) the transition point from KHI-like to RTI-like for the case where the KHI dominates at earlier time and the RTI dominates at later time. It is found that the early main mechanism is related to the shape of the initial interface, which is represented by both the bilateral contact angle θ 1 and the middle contact angle θ 2 . The increase of θ 1 and the decrease of θ 2 have opposite effects on the critical velocity. When θ 2 remains roughly unchanged at 90 degrees, if θ 1 is greater than 90 degrees (such as the parabolic interface), the critical shear velocity increases with the increase of θ 1 , and the ellipse perturbation is its limiting case; If θ 1 is less than 90 degrees (such as the inverted parabolic and the inverted ellipse disturbances), the critical shear velocities are basically the same, which is less than that of the sinusoidal and sawtooth disturbances. The influence of inverted parabolic and inverted ellipse perturbations on the transition point of the RTKHI system is greater than that of other interfaces: (i) For the same amplitude, the smaller the contact angle θ 1 , the later the transition point appears; (ii) For the same interface morphology, the disturbance amplitude increases, resulting in a shorter duration of the linear growth stage, so the transition point is greatly advanced.

show abstract

“…Here we revisit a theoretical model [44] that describes the combined behavior of the R–T and K–H instabilities of a cylindrical interface [45] , [46] , [47] . Consider an infinite annular cylindrical interface as shown in Fig.…”

mentioning

confidence: 99%

A note on the stability characteristics of the respiratory events

Vadivukkarasan¹

2021

European Journal of Mechanics - B/Fluids

Self Cite

View full text Add to dashboard Cite

The present outbreak enables the researchers from fluid mechanics to widen the understanding of expelling respiratory liquids from a unique perspective to diminish the persistence of COVID-19. This article focuses on uncovering the instability mechanism responsible for forming droplets and aerosols during respiratory events such as breathing, talking, coughing and sneezing. We illustrate a mathematical framework by revisiting the model (Vadivukkarasan and Panchagnula, 2017) and show the associated instabilities during respiratory events. We envisage the combined Rayleigh–Taylor–Kelvin–Helmholtz (R–T–K–H) model as a robust tool for respiratory events. This study highlights the distinct possibility of respiratory droplet formation over multiple instabilities and provides a fundamental understanding. We present the different dominant modes through a ternary phase diagram for three-dimensional numbers (Bond number and Weber numbers). Furthermore, this model can be extended phenomenologically to viscous fluids to satisfy mucus and saliva in the respiratory liquids.

show abstract

Temporal instability characteristics of Rayleigh–Taylor and Kelvin–Helmholtz mechanisms of an inviscid cylindrical interface

Cited by 8 publications

References 29 publications

Discrete Boltzmann modeling of Rayleigh-Taylor instability: effects of interfacial tension, viscosity and heat conductivity

Discrete Boltzmann modeling of Rayleigh-Taylor instability: effects of interfacial tension, viscosity and heat conductivity

Effects of the initial perturbations on the Rayleigh-Taylor-Kelvin-Helmholtz instability system

A note on the stability characteristics of the respiratory events

Contact Info

Product

Resources

About