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Projects: Projects for Investigator
Reference Number EP/V00199X/1
Title Secondary currents in turbulent flows over rough walls
Status Started
Energy Categories Renewable Energy Sources(Wind Energy) 5%;
Not Energy Related 95%;
Research Types Basic and strategic applied research 100%
Science and Technology Fields PHYSICAL SCIENCES AND MATHEMATICS (Computer Science and Informatics) 10%;
ENGINEERING AND TECHNOLOGY (Mechanical, Aeronautical and Manufacturing Engineering) 90%;
UKERC Cross Cutting Characterisation Not Cross-cutting 100%
Principal Investigator Dr B (Bharathram ) Ganapathisubramani
No email address given
School of Engineering Sciences
University of Southampton
Award Type Standard
Funding Source EPSRC
Start Date 01 April 2021
End Date 31 March 2025
Duration 48 months
Total Grant Value £774,193
Industrial Sectors Defence and Marine; Aerospace
Region South East
Programme NC : Engineering
Investigators Principal Investigator Dr B (Bharathram ) Ganapathisubramani , School of Engineering Sciences, University of Southampton (99.999%)
  Other Investigator Dr D Lasagna , Sch of Engineering, University of Southampton (0.001%)
  Industrial Collaborator Project Contact , Akzo Nobel (0.000%)
Project Contact , European Office of Aerospace Research and Development (EOARD) (0.000%)
Web Site
Abstract A majority of engineering and environmental flows occur over surfaces that exhibit spatial variations in roughness and/or topography. When a turbulent wall-flow evolves over such surfaces, it may exhibit unusual physical properties, depending on the relationship between the dominant length-scales of the surface and that of the flow. Specifically, when the dominant length-scale(s) of the surface in the cross-stream direction become(s) comparable to the dominant length-scale of the flow (such as boundary layer thickness or water-depth), then the flow also exhibits large-scale spatial heterogeneity that is locked-on to the surface heterogeneity. This flow heterogeneity is expressed in the form of localised secondary currents (SCs) that often extend across the entire depth of the flow and manifest themselves as large 'time-averaged' streamwise vortices accompanied by low- and high-speed regions. This surface-induced flow heterogeneity invalidates some of the fundamental tenets of turbulent wall-flows that were developed for flows over homogeneous surfaces. Therefore, current predictive tools that rely on these tenets can neither accurately predict nor offer insights into the complex physics of flows that contain surface-induced SCs. The significant effects of surface-induced SCs have recently been recognised in at least two disparate areas: 1) Performance of engineering systems such as in-service turbine blades, bio-fouled ship hulls and flow control; and 2) Understanding of the river flow dynamics with applications in flood management, eco-hydraulics and sediment transport. Over recent years, Southampton, Aberdeen, Glasgow and UCL have invested considerable efforts in advancing both these areas. Given the burgeoning interest in this topic, it would be timely to harness the synergies between these four leading groups to develop comprehensive understanding of turbulent flows in the presence of surface-induced SCs and establish a novel transformative framework to predict such flows.This project will leverage the expertise, domain knowledge and infrastructure of four leading groups in the above-mentioned areas to bring about a paradigm shift in our approach to flows over heterogeneous surfaces that generate secondary currents. A comprehensive series of physical experiments (at Southampton & Aberdeen) and complementary numerical simulations (at Glasgow & UCL) will be performed to generate unprecedented data on surface-induced SCs. We will compare and contrast the behaviour of SCs across all four canonical wall-flows (boundary layers, open-channels, pipes and closed-channels) for the first time. The obtained data will underpin identification and validation of potential universalities (and differences) in drag mechanisms and momentum/energy transfer in these flows in the presence of surface-induced SCs. Synthesising the insights obtained from the data, a new framework leading to physics-informed semi-empirical and and theoretically-based numericalmodels will be developed to predict and optimise the influence of surface-induced SCs on turbulent wall-flows relevant to engineering/environmental applications.
Publications (none)
Final Report (none)
Added to Database 11/10/21