Experimental Apparatus for Roll-Wave Measurements and Comparison with a 1D Mathematical Model

Maciel, Geraldo de Freitas; Ferreira, Fabiana de Oliveira; Cunha, Evandro Fernandes da; Fiorot, Guilherme Henrique

doi:10.1061/(asce)hy.1943-7900.0001366

Cited by 11 publications

(6 citation statements)

References 22 publications

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“…Because of the characteristics of the motion form of the roll wave, actual measurement is difficult. Owing to the improvements in science and technology, the research on model optimization and measurement device development has made great progress (Cao et al 2015;Maciel et al 2017). Before this, few experimental studies have been conducted.…”

Section: Introductionmentioning

confidence: 99%

Evolution Rules of Rolling Waves on Slopes Based on Artificial Flat Slopes of Loess

et al. 2020

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We used a fixed-bed flume test and ultrasonic sensor measurement technology to study the evolution of the characteristics of thin-layer flow roll waves on a sloped surface. The results indicated that there was a positive correlation between the velocity of the roll wave and the Reynolds number when the energy slope and roughness were small. In addition, the amplitude of the increase gradually decreased with increases in roughness, and the height of the roll waves showed a single-hump trend of change. When the roughness was relatively small, the frequency of the roll waves increased as the Reynolds number increased, and the ratio of the wavelength to the water depth gradually decreased. As the energy slope increased, both the wave velocity and frequency of the roll waves gradually increased; they peaked when the energy slope was 0.3420. We found that the dominant factors that affected different roll-wave characteristic parameters varied. The roughness of the bed had a relatively prominent impact on the velocity of the roll waves, but the energy slope had a greater effect on the height of the roll waves.

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Section: Introductionmentioning

confidence: 99%

Evolution Rules of Rolling Waves on Slopes Based on Artificial Flat Slopes of Loess

et al. 2020

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“…As far as the roll wave profile is concerned, it is possible to verify that low-frequency waves are more sharply, with characteristics similar to those of shock waves, as experimentally verified in Newtonian and non-Newtonian laminar flows (Fiorot et al, 2015, Maciel et al, 2017, Cunha, 2017. Such finding indicates that the disturbance frequency is an important parameter in the generation and in the characterization of roll waves.…”

Section: Roll Wave Generationmentioning

confidence: 76%

“…Although in reduced numbers, roll wave studies concerning both laminar and turbulent regimes have been experimentally carried out (Brock, 1969;Tamburrino & Ihle, 2013;Fiorot et al, 2015;Maciel et al, 2017;Zhao et al, 2015;Aranda et al, 2016;Miao et al, 2020;Fei et al, 2021). Works based on mathematical and numerical modelling, on the other hand, are more frequent in the literature (Zanuttigh & Lamberti, 2002;Gao et al, 2003;Balmforth & Liu, 2004;Di Cristo & Vacca, 2005;Maciel et al, 2013;Ferreira et al, 2014;Cao et al, 2015;Ivanova et al, 2017;Maciel et al, 2018;Kan et al, 2018;among others).…”

Section: /18mentioning

confidence: 99%

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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“…The ultrasonic system, in this case, has large advantage in relation to the difficulty of laser for such environments. Finally, it is worth mentioning that the technique of ultrasound has been confronted with 1D mathematical model showing errors of 2 to 10% according to [21].…”

Section: Discussionmentioning

confidence: 99%

“…The experimental apparatus consists of several sets, each built separately, with the objective of obtaining the best interaction and connection among them. For more information on the experimental apparatus see [17,21]:…”

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confidence: 99%

Non-intrusive techniques to measure roll waves level evolving in a flume

et al. 2018

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An open-channel experimental set-up is presented in this paper as a tool for examining the presence of instabilities on free-surfaces flows of non-Newtonian fluid. When these flows occur in favorable conditions of inclination, discharge and rheological properties, the propagation of instabilities can evolve into a specific type of wave, known as roll waves. The experimental apparatus developed allows study of stabilized roll waves in many scenarios for non-Newtonian rheology fluids, thereby constituting a highly useful tool for the understanding and control of roll waves. The test fluid used in the experiments was carbopol gel which is rheometrically representative of the muddy material from natural disasters, such as mudflows. Two non-intrusive level measurement systems are proposed (ultrasonic transducer and laser-based absorption technique), and the efficiency of each technique is presented and discussed. Both methods presented relatively low-cost implementation, and calibration procedure assured the quality of the results. The results from the experimental set-up were in agreement in shape and amplitude.

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Experimental Apparatus for Roll-Wave Measurements and Comparison with a 1D Mathematical Model

Cited by 11 publications

References 22 publications

Evolution Rules of Rolling Waves on Slopes Based on Artificial Flat Slopes of Loess

Evolution Rules of Rolling Waves on Slopes Based on Artificial Flat Slopes of Loess

Roll waves and their generation criteria

Non-intrusive techniques to measure roll waves level evolving in a flume

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