Stability analysis of stratified Rayleigh-Bénard-Poiseuille convection. Part III: Interface deformation

Fontana, Éliton; Mancusi, Erasmo; Souza, Sabrina da Silva de; Souza, Selene M.A. Guelli U. de

doi:10.1016/j.ces.2019.03.086

Cited by 4 publications

(1 citation statement)

References 17 publications

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“…Computational fluid dynamics (CFD) has become an important method to study multiphase flow. Éliton Fontana [18] used LSA and CFD techniques to track the shear flow interface position. The results showed that the deformation of the fluid interface under different viscosities and thermal conductivities was significant.…”

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Study on gas velocity distribution of gas-liquid stratified flow based on numerical simulation and PIV

Liu,

Zhao,

Han

et al. 2023

Preprint

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The velocity is an important parameter for the fluid flow characteristics in the two-phase flow. In the gas-liquid two-phase stratified flow, the most easily obvious force equilibrium point is at the peak point of the gas phase velocity. This study is of great significance for constructing the two-phase stratified flow model. In this paper, the flow field characteristics of the gas-liquid stratified flow are investigated by numerical simulation and a theoretical model of the gas phase peak velocity position is established. The accuracy of numerical simulation is illustrated by comparing classical prediction model and PIV experimental data. The results indicate that the position of gas-liquid interface moves down and the position of gas phase peak velocity moves up with an increase in gas mass flow rate. Conversely, when gas phase mass flow rate is constant, the position of gas-liquid interface moves up and the position of gas phase peak velocity moves down with an increase in liquid mass flow rate. By exploring the relationship between the position of the peak gas velocity point and ratio of the Reynolds number, it is found that the position of the gas peak velocity has a linear relationship with the gas-liquid Reynolds number. The multiple correlation coefficient is 0.85, obtained by linear regression fitting which stated that there is a strong linear relationship between the two variables.

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confidence: 99%

Study on gas velocity distribution of gas-liquid stratified flow based on numerical simulation and PIV

Liu,

Zhao,

Han

et al. 2023

Preprint

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Linear temporal stability analysis on the inviscid sheared convective boundary layer flow

2022

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A linear temporal stability analysis is conducted for inviscid sheared convective boundary layer flow, in which the sheared instability with stable stratification coexists with and caps over the thermal instability with unstable stratification. The classic Taylor-Goldstein equation is applied with different stratification factors Js and Jb in the Brunt-Väisälä frequency, respectively. Two shear-thermal hybrid instabilities, the hybrid shear stratified (HSS) and hybrid Rayleigh-Bénard (HRB)modes, are obtained by solving the eigenvalue problems. It is found that the temporal growth rates of the HSS and HRB modes vary differently with increased Jb in two distinct wavenumber (ã) regions defined by the intersection point between the stability boundaries of the HSS and HRB modes. Based on Jb,cr where the temporal growth rate of the HSS and HRB are equal, a map of the unique critical boundary, which separates the effective regions of the HSS and HRB modes, is constructed and found to be dependent on Js, Jb and ã. The examinations of the subordinate eigenfunctions indicate that: the shear instability is well developed in the HSS mode, in which the large vortex structures may prevail and suppress the formation of convective rolls; the shear instability in the HRB mode is either 'partly developed' when Jb< Jb,cr or 'undeveloped' when Jb> Jb,cr, thus only plays a secondary role to modify the dominant convective rolls; and as Jb increases the eigenfunctions of the HSS mode exhibit different transitional behaviors in the two regions, signifying the 'shear enhancement' and 'shear sheltering' of the entrainment of buoyancy flux.

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Interfacial flow dynamic micro-response and spatiotemporal evolution of flow pattern for thermocapillary–buoyancy convection in a liquid bridge

Yang

Deng

2020

New J. Phys.

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Compared with the former studies, the perturbation behavior of thermocapillary–buoyancy convection caused by the simultaneous coupling response of the microscale surface flow, free surface deformation and spatiotemporal evolution of flow patterns is revealed by the combination of experimental and numerical methods for the first time. The free surface morphology transforms from the ‘Ƨ’-shape into the twisted ‘M’-shape in the corresponding balanced stage of thermocapillary–buoyancy convection (at t = 975, Bod = 251.5), and eventually becomes ‘Ƨ’-shape in the corresponding third stage (Bod = 229.9). Meanwhile, there is a weak response of the free surface flow during each transition stage accompanied by periodic hydrothermal waves. The perturbation characteristics of the velocity, the temperature and the transverse location of surface flow are the most prominent at the intermediate height of liquid bridge (y = 0.2). The characteristic of longitudinal velocity mainly presents as the pulsation, while there is also the pulsation inside the oscillation of transverse velocity with the large amplitude (the oscillating period of 2f u = 7.2 s and the amplitude of A u = 0.0057). The periodic characteristic of temperature oscillation is obvious (2f θ = 0.2 s, A u = 0.015).

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Stability analysis of stratified Rayleigh-Bénard-Poiseuille convection. Part III: Interface deformation

Cited by 4 publications

References 17 publications

Study on gas velocity distribution of gas-liquid stratified flow based on numerical simulation and PIV

Study on gas velocity distribution of gas-liquid stratified flow based on numerical simulation and PIV

Linear temporal stability analysis on the inviscid sheared convective boundary layer flow

Interfacial flow dynamic micro-response and spatiotemporal evolution of flow pattern for thermocapillary–buoyancy convection in a liquid bridge

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