Towards a hydrodynamic modelling framework appropriate for applications in urban flood assessment and mitigation using heterogeneous computing

Abstract

We present a new hydrodynamic modelling framework capable of fully exploiting modern graphics and central processing units (GPUs and CPUs) from any of the mainstream vendors, to be used in the design and assessment of sustainable drainage systems. A finite-volume Godunov-type scheme is combined with the HLLC Riemann solver to create a robust numerical model which correctly addresses wetting and drying and transient flow conditions, and is suitable for application to a wide range of flood simulations. The software is tested with a three day flood event in Carlisle during 2005, at resolutions from 25 m to 2 m. Run-times are significantly reduced without compromising numerical accuracy. Excellent agreement is found between the simulation results and a comprehensive post-event survey. Changes in sensitivity to Manning's n are examined at different resolutions, with changes to the floodplain found to have little influence at 2 m resolution.

Keywords::

• graphics processing unit (GPU)
• finite-volume Godunov-type scheme
• shallow water equations
• urban flooding
• sustainable urban drainage

Acknowledgements

Gratitude is expressed to Dr Jeff Neal of Bristol University and his colleagues, and the Environment Agency for collecting and supplying necessary data.

Funding

The authors are grateful to Advanced Micro Devices Inc. for supplying the AMD FirePro V7800 GPU device. The NVIDIA Tesla M2075 device used is part of a larger system funded by the UK Engineering and Physical Sciences Research Council (EP/K031678/1).