Sonic Characterisation of Water Surface Waves, Turbulence, Mixing and Bed Friction in Shallow Water Flows
Lead Research Organisation:
Cardiff University
Department Name: Sch of Engineering
Abstract
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Publications
Ulrich R. Kamalian (Author)
(2012)
Development of a 3-D non-hydrostatic model for free surface flows
Xie Z
(2021)
Large-eddy simulation of turbulent free surface flow over a gravel bed
in Journal of Hydraulic Research
Xie Z
(2014)
Turbulence characteristics in free-surface flow over two-dimensional dunes
in Journal of Hydro-environment Research
Xie Z
(2013)
Large-eddy simulation of turbulent open-channel flow over three-dimensional dunes
in Journal of Hydraulic Research
Xie Z
(2013)
Large-eddy simulation of the turbulent structure in compound open-channel flows
in Advances in Water Resources
Zhihua Xie (Author)
(2012)
LES of flow over 3D dunes
Zhihua Xie (Author)
(2012)
A Cartesian grid method for shallow water flows over a gravel bed
| Description | A LES model has been developed to predict shallow water free surface flows. The dynamic sub-grid scale model is employed in the model, with the partial cell treatment being implemented on a Cartesian grid to represent the bed topography. The VOF method is used to capture the moving water surface. Model simulations have been undertaken to get a better understanding of coherent flow structures in shallow water flows, and the interactions these features have with the bed surface roughness and surface water waves. There are four main project findings. (1) The movement of water surface has a significant effect on the distributions of turbulence intensities and the Reynolds stresses along the water depth. (2) For very shallow water flows the value of predicted surface fluctuations is in an order of 1% of the water depth. As the submergence ratio increases, a larger velocity is required to maintain the level of fluctuation. (3) Three-dimensional dunes induce a system of counter-rotating secondary currents, directing high-speed fluid downwards and low-speed fluid upwards. (4) In regular-shaped compound channels the temporal and spatial velocity fields are significantly different at different cross sections, but their time-averaged secondary velocity distributions are similar. |
| Exploitation Route | The findings from the research potentially can be used to develop equipment for rapid measurement of bed roughness in shallow rivers and channels. This would help river managers and engineers to determine flow rates, which would be very useful in flood risk assessment. The new understanding of shallow water flows could also be used to develop new software to enable improved predictive capability to be developed. The research findings have been presented to Yorkshire Water and Halcrow through regular meetings during the whole project period. The findings have also been presented in three international conferences and submitted to three international journals, with one published, one in print and one under review. The main outcome is the development of an acoustic-based systems capable of the remote measurement of bed friction from rapid scanning of the air/water interface. This is developed at Bradford University and the exploit routes are described in the report by the Bradford team. |
| Sectors | Environment |
| Description | The current project is a part of a joint project between the Cardiff University team and a team at the University of Bradford led by Professor Simon Tait (EP/G015341/1). The Cardiff team has developed 3-D large eddy simulation model to simulate coherent flow structures in shallow water flows, and the interactions these features have with the bed surface roughness and surface water waves. The main outcome of the project was the development of an acoustic-based systems capable of the remote measurement of bed friction of shallow water flows from rapid scanning of the air/water interface. This technology will have a wide range of potential applications, e.g. improved accuracy in modelling riverine flows (particularly with flooding), catchment and floodplain surface hydrologic predictions, improved predictions of flow in partially filled pipes, estuarine hydrodynamics for unsteady frictional flows over intertidal reaches and water quality/turbidity predictions in turbulent flows. |
| First Year Of Impact | 2013 |
| Sector | Communities and Social Services/Policy,Environment |
| Impact Types | Societal |