eprintid: 10199602 rev_number: 8 eprint_status: archive userid: 699 dir: disk0/10/19/96/02 datestamp: 2024-11-05 09:37:45 lastmod: 2024-11-05 09:37:45 status_changed: 2024-11-05 09:37:45 type: proceedings_section metadata_visibility: show sword_depositor: 699 creators_name: Chung, SW creators_name: Luo, Q creators_name: Stoesser, T title: Large-scale motion over spanwise heterogeneous bed roughness ispublished: pub divisions: UCL divisions: B04 divisions: F44 note: This version is the author-accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. abstract: This paper presents results of large-eddy simulations (LES) of open-channel flow over a bed with spanwise heterogeneous roughness. The smooth channel bed is roughened via streamwise-orientated triangular strips. The flows reported are at moderate Reynolds and Froude numbers and at varying relative submergence (i.e. water-depth-to-strip-height-ratio). Due to the presence of longitudinal strips, the flow exhibits significantly different mean flow characteristics than the analogue flow over a smooth channel bed. The strip roughness induces turbulence anisotropy which leads to the formation of strong secondary currents, featuring upflow above strips and downflow in the troughs between strips. It is found that the spacing of the strips and the relative submergence of the flow has a profound influence on the strength of secondary currents and the large-scale turbulent motion. date: 2024-08-14 date_type: published publisher: CRC Press official_url: https://doi.org/10.1201/9781003323037-12 full_text_type: other language: eng verified: verified_manual elements_id: 2311584 doi: 10.1201/9781003323037-12 isbn_13: 9781003323037 lyricists_name: Stoesser, Thorsten lyricists_id: TSTOE28 actors_name: Stoesser, Thorsten actors_id: TSTOE28 actors_role: owner full_text_status: restricted pres_type: paper series: Conference on Fluvial Hydraulics publication: River Flow - Proceedings of the 11th Conference on Fluvial Hydraulics, 2022 volume: 2022 place_of_pub: London, UK pagerange: 83-89 event_title: 11th Conference on Fluvial Hydraulics 2022 book_title: River Flow 2022 - Proceedings of the 11th Conference on Fluvial Hydraulics editors_name: Ferreira da Silva, Ana Maria editors_name: Rennie, Colin editors_name: Gaskin, Susan editors_name: Lacey, Jay editors_name: MacVicar, Bruce citation: Chung, SW; Luo, Q; Stoesser, T; (2024) Large-scale motion over spanwise heterogeneous bed roughness. In: Ferreira da Silva, Ana Maria and Rennie, Colin and Gaskin, Susan and Lacey, Jay and MacVicar, Bruce, (eds.) River Flow 2022 - Proceedings of the 11th Conference on Fluvial Hydraulics. (pp. pp. 83-89). CRC Press: London, UK. document_url: https://discovery.ucl.ac.uk/id/eprint/10199602/1/RiverFlow2024_FreeSurface_SChung.pdf