| Full text | |
| Author(s): |
Total Authors: 3
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| Affiliation: | [1] Univ Estadual Paulista, Ilha Solteira, SP - Brazil
Total Affiliations: 1
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| Document type: | Journal article |
| Source: | RBRH-REVISTA BRASILEIRA DE RECURSOS HIDRICOS; v. 26, 2021. |
| Web of Science Citations: | 0 |
| Abstract | |
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. (AU) | |
| FAPESP's process: | 20/07822-0 - Experimental device and numerical support in order to study mudflows: its laws of evolution, runout distances and velocity field |
| Grantee: | Geraldo de Freitas Maciel |
| Support Opportunities: | Regular Research Grants |