Details of Grant 

EPSRC Reference:	EP/C530659/1
Title:	Smoothed Particle Hydrodynamics (SPH) For Turbulence and Aerated/Violent Surface Motion
Principal Investigator:	Laurence, Professor D
Other Investigators:	Stansby, Professor PK
Researcher Co-Investigators:
Project Partners:
Department:	Mechanical Aerospace and Civil Eng
Organisation:	University of Manchester, The
Scheme:	Standard Research (Pre-FEC)
Starts:	01 January 2005	Ends:	30 June 2008	Value (£):	202,561
EPSRC Research Topic Classifications:	Aerodynamics
EPSRC Industrial Sector Classifications:	Manufacturing
Related Grants:
Panel History:
Summary on Grant Application Form
Traditional Computational Fluid Dynamics (CFD) is quite successful in predicting many flows but has difficulty in resolving freesurface motion which is aerated (2-phase), as in breaking waves, or undergoing massive accelerations (violent), when waves hit an obstacle. This is because a mesh is used which is either fixed, capturing the distorted aerated interface, or dynamic and moving with the interface; both are problematic for numerical simulation and intuitively unnatural.The Smoothed Particle Hydrodynamics (SPH) method however does not rely on a mesh. Instead, properties of the flow such as velocity, pressure, density, are carried by freely moving particles. Its main present weakness lies in its representation (modelling) of turbulence and it is relatively untried for aerated or violent free-surface motions. These free-surface motions generate turbulence and so it makes sense to develop methods for refined turbulence modelling and basic free-surface motion in parallel, then combining into a general method. There are many engineering applications and here we are mainly concerned with coastal hydrodynamics. Incorporation of realistic turbulence in SPH presents some special challenges.SPH naturally exhibits random motions which present similarities with turbulence. In Large Eddy Simulation (LES) for standard CFD the larger turbulent eddies are computed directly within the background or mean flow. However the range of scales of turbulent eddies in a turbulent flow is so vast that most of the smaller scales fall below the mesh size. They cannot be computed directly and their effect must be modelled/reconstructed. Similarly particles in SPH represent lumps of fluid, which are fairly large compared to the smaller eddies, and the effects of the smaller scales on the larger scales need to be simulated. One part of the project will attempt to combine the aforementioned numerical shortcoming of SPH (the artificial numerical random motion) with the LES modelling approach, by taking advantage of the randomness rather than eliminating it.The second part will concentrate on free surface flows with relatively simple turbulence models. One great advantage of SPH compared to standard CFD is its ability to represent highly distorted and even fragmented gas-liquid interfaces. Submerged pockets of air acting as air cushions greatly influence the internal forces, and are extremely challenging for computer simulations. 'SPH with LES' is not expected to be cost effective for daily engineering studies for another ten years or so and the project will thus include significant numerical optimisation with use of parallel computing.Beyond coastal engineering, this novel numerical tool will be also relevant to various industrial sectors involving multiphase flows: airtwater in nuclear reactors, air/oil mixtures in pipelines, chemical engineering, steel casting etc. An application to slug flow in pipes (where large pockets of air can lead to destructive 'water hammer') will thus also be demonstrated.
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Organisation Website:	http://www.man.ac.uk