Turbulent puffs in transitional pulsatile pipe flow at moderate pulsation amplitudes

DOI

We show that, in the transitional regime of pulsatile pipe flow, at moderate-to-high amplitudes 0.5≲𝐴≲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≲𝐴≲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.

Identifier
DOI https://doi.org/10.1594/PANGAEA.969126
Related Identifier References https://journals.aps.org/prfluids/abstract/10.1103/PhysRevFluids.9.024601
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.969126
Provenance
Creator Morón, Daniel ORCID logo; Avila, Marc ORCID logo
Publisher PANGAEA
Publication Year 2024
Funding Reference German Research Foundation https://doi.org/10.13039/501100001659 Crossref Funder ID AV 120/6-1 Instabilities, Bifurcations and Migration in Pulsating Flow (FOR 2688)
Rights Creative Commons Attribution 4.0 International; https://creativecommons.org/licenses/by/4.0/
OpenAccess true
Representation
Resource Type Dataset
Format text/tab-separated-values
Size 123 data points
Discipline Earth System Research