Study on laminar turbulent transition in square arrayed rod bundles

Carolina S.B. Dutra, Elia Merzari

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations


The study of coolant flow behavior in rod bundles is of relevance to the design of nuclear reactors. Although laminar and turbulent flows have been researched extensively, there are still gaps in understanding the process of laminar-turbulent transition. Such a process may involve the formation of a gap vortex street as the consequence of a related linear instability. In the present work, a parametric study was performed to analyze the spatially developing turbulence in a simplified geometry setting. The geometry includes two square arrayed rod bundle subchannels with periodic boundary conditions in the cross-section. The pitch-to-diameter ratios range from 1.05 to 1.20, and the length of the domain was selected to be 100 diameters. No-slip condition at the wall, and inlet-outlet configuration were employed. Then, to investigate the stability of the flow, the Reynolds number was varied from 250 to 3000. The simulations were carried out using the spectral-element code Nek5000, with a Direct Numerical Simulation (DNS) approach. Data were analyzed to examine this Spatio-temporal developing instability. In particular, we evaluate the location of onset and spatial growth of the instability.

Original languageEnglish (US)
Title of host publicationStudent Paper Competition
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Print)9784888982566
StatePublished - 2021
Event2021 28th International Conference on Nuclear Engineering, ICONE 2021 - Virtual, Online
Duration: Aug 4 2021Aug 6 2021

Publication series

NameInternational Conference on Nuclear Engineering, Proceedings, ICONE


Conference2021 28th International Conference on Nuclear Engineering, ICONE 2021
CityVirtual, Online

All Science Journal Classification (ASJC) codes

  • Nuclear Energy and Engineering


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