eprintid: 10116515 rev_number: 19 eprint_status: archive userid: 608 dir: disk0/10/11/65/15 datestamp: 2020-12-08 10:04:01 lastmod: 2021-11-19 23:30:15 status_changed: 2020-12-08 10:04:01 type: proceedings_section metadata_visibility: show creators_name: Nassrullah, S creators_name: Stubbs, A creators_name: Stoesser, T creators_name: Wilson, CAME title: The Validation of the Logarithmic Velocity Profiles Above Rough-Bed Flows ispublished: pub divisions: UCL divisions: B04 divisions: C05 divisions: F44 keywords: Rough gravel riverbed, Acoustic Doppler Velocimeter (ADV), Rough surface turbulence, Logarithmic velocity profile, Hydraulically rough flow. note: This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. abstract: Knowledge of rough-bed flows is important for river engineers and environmental scientists alike asmost natural surface water flows are considered within the hydraulically rough flow regime. This study helps our understanding of flow characteristics above a rough gravel riverbed, which in-turn, affect fine sediment and nutrient transport which can have a large impact on aquatic organisms and the ecosystem at large. High velocity flows over rough beds result in increased turbulence intensity and contribute to the suspension of fine sediment. Therefore, the main aim of this study is to validate first-order turbulence statistics in the form of spatially-averaged streamwise velocity profiles of the flow over a highly-porous rough bed at intermediate relative submergence. The experiments were conducted under uniform flow conditions in Cardiff University’s Hydraulics Laboratory using a narrow flume, 10 m long, 0.3 m wide, and 0.3 m deep, equipped with a bed of natural gravel with an average diameter of 20 mm. A side looking Acoustic Doppler Velocimeter (ADV) was used to measure velocity profiles at 40 random locations within the sampling area. The results show that a logarithmic velocity profile is valid for rough-bed flows with a von Karman’s constant of 0.41 and a Nikuradse equivalent sand roughness of between 1.5d and 2d. date: 2019-09-01 date_type: published publisher: The International Association for Hydro-Environment Engineering and Research (IAHR) official_url: http://dx.doi.org/10.3850/38wc092019-0421 oa_status: green full_text_type: pub language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 1833654 doi: 10.3850/38wc092019-0421 lyricists_name: Stubbs, Alexander lyricists_id: ASTUB89 actors_name: Dewerpe, Marie actors_id: MDDEW97 actors_role: owner full_text_status: public publication: 38th IAHR World Congress - "Water: Connecting the World" place_of_pub: Panama City, Panama event_title: 38th IAHR World Congress institution: 38th IAHR World Congress book_title: Proceedings of the 38th IAHR World Congress (Panama) citation: Nassrullah, S; Stubbs, A; Stoesser, T; Wilson, CAME; (2019) The Validation of the Logarithmic Velocity Profiles Above Rough-Bed Flows. In: Proceedings of the 38th IAHR World Congress (Panama). The International Association for Hydro-Environment Engineering and Research (IAHR): Panama City, Panama. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10116515/1/THEVALIDATIONOFTHELOGARITHMICVELOCITYPROFILESABOVEROUGH-BEDFLOWS.pdf