Unstable yet static initial state: A universal method for studying Rayleigh-Taylor instability and lock exchange

Kobayashi, Kazuya U.; Kurita, Rei

doi:10.1103/physrevfluids.4.013901

Cited by 4 publications

(5 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Those results suggest that there is a positive correlation between and L although the data is distributed. The result is roughly consistent with a previous experimental result in a low viscosity fluid system, when at the beginning 23 .…”

Section: Resultssupporting

confidence: 93%

“…It is worth noting that the interfacial energy between the two gelatin solutions is negligible, much like the interface between air and grains. Our experimental setup makes it possible to observe the formation of the Rayleigh–Taylor-like instability from the very beginning, allowing accurate observation of how the distance between fingers changes over time 23 . In addition, we may also systematically investigate how the gravitational instability changes in response to different viscosity and density gradients by changing the bottom temperature and the composition of the upper and lower layers (see Fig.…”

Section: Resultsmentioning

confidence: 99%

“…However, in granular materials, new fingers are born between existing fingers 17 . This is never observed in fluid systems 6 , 18 – 23 . Despite recent developments in granular physics, the mechanism behind (ii) and (iii) above remains unclear.…”

Section: Introductionmentioning

confidence: 88%

“…Details of the experimental method can also be found in Ref. 23 . The room temperature was set to 21.3 °C with a standard air conditioner.…”

Section: Materials and Experimental Methodsmentioning

confidence: 99%

See 3 more Smart Citations

Key connection between gravitational instability in physical gels and granular media

Kobayashi

Kurita

2022

Sci Rep

Self Cite

View full text Add to dashboard Cite

We study gravitationally-driven (Rayleigh–Taylor-like) instability in physical gels as a model for the behavior of granular media falling under gravity; physical gels have a structural elasticity and may be fluidized, capturing both the solid and liquid properties of granular systems. Though ubiquitous in both industrial and natural contexts, the unique static and dynamic properties of granular media remain poorly understood. Under the action of a gravitational force, granular materials may flow while exhibiting heterogeneous rigidity, as seen during e.g., avalanches or landslides. Though the onset of this gravitational “instability” has been addressed, the mechanism behind its incidence is not yet understood. We find key quantitative similarities between Rayleigh–Taylor-like instability in physical gels and granular systems. In particular, we identify a common scaling law, showing that the instability is chiefly governed by the thickness of the flowable region.

show abstract

Section: Resultssupporting

confidence: 93%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 88%

“…Details of the experimental method can also be found in Ref. 23 . The room temperature was set to 21.3 °C with a standard air conditioner.…”

Section: Materials and Experimental Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Key connection between gravitational instability in physical gels and granular media

Kobayashi

Kurita

2022

Sci Rep

Self Cite

View full text Add to dashboard Cite

show abstract

“…Based on initial pattern of the perturbation, the RTI can be divided into the single-mode and multimode [12][13][14] instabilities. The single-mode RTI in comparison to the multimode example is simple and ideal, but the study of single-mode phenomenon is still very important not only in its own interests to fluid mechanics, but also that the turbulent growth constant in the multimode instability has a direct relationship with the single-mode terminal velocity [15].…”

Section: Introductionmentioning

confidence: 99%

Late-time description of immiscible Rayleigh-Taylor instability: A lattice Boltzmann study

Huang¹,

Xia²,

Liang³

et al. 2020

Preprint

View full text Add to dashboard Cite

In this paper, the late-time description of immiscible Rayleigh-Taylor instability (RTI) in a long duct is investigated over a comprehensive range of the Reynolds numbers (1 ≤ Re ≤ 10000) and Atwood numbers (0.05 ≤ A ≤ 0.7) based on the mesoscopic lattice Boltzmann method. We first reported that the instability with a moderately high Atwood number of 0.7 undergoes a sequence of distinguishing stages at a high Reynolds number, which are termed as the linear growth, saturated velocity growth, reacceleration and chaotic development stages. The spike and bubble at the secondary stage evolve with the constant velocities and their values agree well with the analytical solutions of the potential flow theory. The duration of the spike saturated velocity stage is very shorter than that of the bubble, implying the asymmetric developments between the spike and bubble fronts. Owing to the increasing strengths of the formed vortices, the movements of the spike and bubble are accelerated such that their velocities exceed than the asymptotic values and the evolution of the instability then enters into the reacceleration stage. Lastly, the curves for the spike and bubble velocities have some fluctuations at the chaotic stage and also a complex interfacial structure with large topological change is observed, while it still preserves the symmetry property with respect to the central axis. To determine the nature of the late-time growth, we also calculated the spike and bubble growth rates by using five popular statistical methods and two comparative techniques are recommended, resulting in the spike and bubble growth rates of about 0.13 and 0.022, respectively. When the Reynolds number is gradually reduced, some later stages such as the chaotic and reacceleration stages cannot be reached successively and the structure of the interface in the evolutional process becomes relatively smooth. The influence of the fluid Atwood number is also examined on the late-time RTI development at a large Reynolds number.It is found that the sustaining time for the saturated velocity stage decreases with the Atwood number. The spike late-time growth rate shows an overall increase with the Atwood number, while it has little influence on the bubble growth rate being approximately 0.0215.

show abstract

Exchange flows in axially rotating pipes

2020

View full text Add to dashboard Cite

Unstable yet static initial state: A universal method for studying Rayleigh-Taylor instability and lock exchange

Cited by 4 publications

References 26 publications

Key connection between gravitational instability in physical gels and granular media

Key connection between gravitational instability in physical gels and granular media

Late-time description of immiscible Rayleigh-Taylor instability: A lattice Boltzmann study

Exchange flows in axially rotating pipes

Contact Info

Product

Resources

About