Turbulent puffs in transitional pulsatile pipe flow at moderate pulsation amplitudes
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| Format: | Dataset Open Access |
| Sprache: | en |
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2024
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| _version_ | 1867171890668240896 |
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| author | Morón, Daniel Avila, Marc |
| author_facet | Morón, Daniel Avila, Marc |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | We show that, in the transitional regime of pulsatile pipe flow, at moderate-to-high amplitudes 0.5≲ ≲1, the first long-lived turbulent structures are localized and take the form of the puffs and slugs observed in statistically steady pipe flow. We perform direct numerical simulations at many pulsation frequencies (Wo), amplitudes, and Reynolds number (Re) and observe different dynamics of puffs and slugs. At certain flow parameters we find, using a causal analysis, that puffs actively make use of linear instabilities in the laminar Sexl-Womersley (SW) profile to survive the pulsation. Using all these lessons learned, we extend a low-order model by Barkley et al. [Nature (London) 526, 550 (2015)] to reproduce these dynamics. We find a good agreement between the extended model and our numerical results in a broad parametric space of pulsation amplitudes 0.5≲ ≲1, frequencies Wo≳5 and 2100≤Re≤3000. With the help of our numerical results, causal analysis and model, we determine that turbulence production has two sources at these flow parameters: the mean shear as in statistically steady pipe flow and the instabilities of the instantaneous pulsatile mean profile. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_969126 |
| institution | PANGAEA |
| language | en |
| publishDate | 2024 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Turbulent puffs in transitional pulsatile pipe flow at moderate pulsation amplitudes Morón, Daniel Avila, Marc Analytical method; Binary Object; Binary Object (File Size); causality; Description; direct numerical simulation; Figure; File format; File name; Numerical simulated; reduced-order model of turbulence; Title; transitional regime; Variable We show that, in the transitional regime of pulsatile pipe flow, at moderate-to-high amplitudes 0.5≲ ≲1, the first long-lived turbulent structures are localized and take the form of the puffs and slugs observed in statistically steady pipe flow. We perform direct numerical simulations at many pulsation frequencies (Wo), amplitudes, and Reynolds number (Re) and observe different dynamics of puffs and slugs. At certain flow parameters we find, using a causal analysis, that puffs actively make use of linear instabilities in the laminar Sexl-Womersley (SW) profile to survive the pulsation. Using all these lessons learned, we extend a low-order model by Barkley et al. [Nature (London) 526, 550 (2015)] to reproduce these dynamics. We find a good agreement between the extended model and our numerical results in a broad parametric space of pulsation amplitudes 0.5≲ ≲1, frequencies Wo≳5 and 2100≤Re≤3000. With the help of our numerical results, causal analysis and model, we determine that turbulence production has two sources at these flow parameters: the mean shear as in statistically steady pipe flow and the instabilities of the instantaneous pulsatile mean profile. |
| title | Turbulent puffs in transitional pulsatile pipe flow at moderate pulsation amplitudes |
| topic | Analytical method; Binary Object; Binary Object (File Size); causality; Description; direct numerical simulation; Figure; File format; File name; Numerical simulated; reduced-order model of turbulence; Title; transitional regime; Variable |
| url | https://doi.org/10.1594/PANGAEA.969126 |