Al-Shamaa B, Wierschem A (2024)
Publication Type: Journal article
Publication year: 2024
Book Volume: 987
Article Number: A39
DOI: 10.1017/jfm.2024.424
Turbulence in gravity-driven film flow is usually discussed in terms of three-dimensional solitary-wave pulses as they are frequently observed in flows along smooth walls. Here, we show that free-surface turbulence arises in films along rippled substrates, as they are commonly employed in process engineering applications, already at rather low Reynolds numbers from the irregular break-up of the solitary-wave fronts. Short waves in the capillary regime replace the broken solitary waves beyond a certain Reynolds number. The crossover coincides with the occurrence of steady three-dimensional surface patterns upstream, which suppress travelling waves. The waves show power spectral densities with power-law exponents typical for weak capillary-wave turbulence. With increasing Reynolds number, the steepness of the power law declines to lower levels.
APA:
Al-Shamaa, B., & Wierschem, A. (2024). Surface turbulence in film flow over periodic ripples. Journal of Fluid Mechanics, 987. https://doi.org/10.1017/jfm.2024.424
MLA:
Al-Shamaa, Bashar, and Andreas Wierschem. "Surface turbulence in film flow over periodic ripples." Journal of Fluid Mechanics 987 (2024).
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