On the applicability of minimum channel length criterion for roll-waves in mud-flows

Cristo, Cristiana Di; Iervolino, Michele; Vacca, Andrea

doi:10.2478/johh-2013-0036

Cited by 20 publications

(7 citation statements)

References 46 publications

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“…Such finding is in accordance with the experimental results of Forterre & Pouliquen (2003). Additionally, a minimal channel length ( min L ) is necessary for the propagation of stabilized roll waves (Di Cristo et al, 2013a). Both generation criteria ( min Fr Fr > , and…”

Section: Introductionsupporting

confidence: 88%

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Roll waves and their generation criteria

Ferreira

Maciel

Pereira

2021

RBRH

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Pulsating waves (also known as roll waves) might occur on the free surface of extreme events like mud and debris flows, among others, usually intensifying the caused damage. This technical note aims to inform about the roll wave phenomenon developing in a free-surface laminar flow, and analyze its generation criteria, centered on the concepts of Froude number and disturbance frequency. The complete linear stability analysis of the new depth-averaged model was proven a useful theoretical tool in determining new generation criteria for roll waves developing in non-Newtonian fluids. The results showed that the roll wave generation depends on two criteria: the first is associated to the minimum Froude number, and the second is related to the cut-off frequency. In addition, we have confirmed that the new generation criteria can be verified via numerical simulation based on a second model with full equations (Fluent software). Globally, the emergence of roll waves is favored by the non-Newtonian properties of the flowing fluid and the fact that the cut-off frequency decreases along with the minimum Froude number. Lastly, both generation criteria were tested in order to examine a case study involving the occurrence of roll waves in a watershed.

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Section: Introductionsupporting

confidence: 88%

“…Value attributed in the numerical test. (2) All minimal channel lengths min L(Di Cristo et al, 2013a) were verified.…”

mentioning

confidence: 99%

Roll waves and their generation criteria

Ferreira

Maciel

Pereira

2021

RBRH

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“…2(a) shows that the waves amplitude increases linearly at the entrance of the channel and then reaches a finite constant. The roll-waves generation depend on the length of the channel, as indicated by Di Cristo et al [33]. This saturation is accompanied by steep fronts, similar to those shown in Fig.…”

Section: Finite Amplitude 2-d Wavessupporting

confidence: 76%

Nonlinear evolution of viscoplastic film flows down an inclined plane

et al. 2023

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In this article, we experimentally investigate the non-linear behavior of a viscoplastic film flow down an inclined plane. We focus on the non-linear instabilities that appear as roll waves. Roll waves are generated by perturbing a permanent flow of Herschel-Bulkley fluid (Carbopol 980) at low frequencies. To determine the local thickness of the film, we used a laser sensor and a camera to globally capture the transverse shape of the waves. For a regular forcing, the results show the existence of different regimes. First, we observe primary instabilities below the cut-off frequency at the entrance of the channel. After the exponential growth of the wave in the linear regime, we recognize the non-linear dynamics with the existence of finite amplitude waves. This finite amplitude depends on the frequency, the Reynolds number and the inclination angle. The results show that this instability is supercritical. At moderate Reynolds numbers, the finite 2-D waves become sensitive to transverse perturbations, due to a secondary instability, and become 3-D waves. The experimental results illustrate a phenomenology of viscoplastic film flows similar to Newtonian fluids, except for the capillary waves.

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“…[9,[12][13][14]38]), but rather limitedly to analyze the performance of simplified flood routing models. Di Cristo et al [15] and Di Cristo et al [16] analyzed the performance of three different approximations, i.e.…”

Section: Introductionmentioning

confidence: 99%