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RESEARCH
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Smoothed Particle
Hydrodynamics (SPH)
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Presently, I am researching a number of different features of
SPH for free-surface flows. These include:
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Implementation of Open Boundaries
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Incorporating an LES Sub-Particle Scale (SPS) scheme to capture
coherent turbulent structures
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Tsunami modelling
Plunging breaking wave on a beach:
Background
Smoothed
Particle
Hydrodynamics (SPH) describes a fluid by replacing its continuum
properties with locally (smoothed) quantities at discrete Lagrangian
locations, so it is a meshless
method.
The technique was developed originally by Lucy (1977) and Gingold and
Monaghan
(1977) for the simulation of nonaxisymmetric phenomena in
astrophysics. A major attraction of the SPH technique is that the
need for fixed computational grids is removed when calculating spatial
derivatives. Instead, estimates of derivatives are provided by
analytical expressions offering a distinct advantage over other
methods, in that there is no meshing
required. Furthermore, the domain can be multiply
connected, and there is no need for special treatment of the free
surface (most computational methods are Eulerian and require additional
modeling (Lagrangian) to determine the free surface location with
time); thus splashing, and other flows that result in fluid separation,
are modeled as readily as other flows.
The SPH method has been used by Monaghan and his co-workers to describe
a variety of free surface flows including solitary wave propagation
over a planar beach (Monaghan and Kos 1999), plunging breakers (Tulin
and Landrini 2000), solid bodies impacting on the surface (Monaghan
2000) and dam break simulations (Monaghan 1994). The method
predicts fluid pressure, velocities, energy and particle trajectories
for many types of flows making it ideal for identifying/elucidating
formation mechanisms of complicated flow phenomena that were hitherto
intractable. Additionally, using a similar particle technique
known as the Moving Particle Semi-Implicit (MPS) method, Koshizuka et al. (1998) and Gotoh et al. (2002) present results for
the movement of passively floating bodies in the surf zone and an open
channel, respectively. Thus, particle methods now also represent
a viable method for simulating complicated free-surface flows.
The raw method of SPH for free-surface flows has various problems
associated with its implementation, for instance, boundary conditions
and description of viscous effects. Hence, much research in
the SPH community is currently underway on developing various
techniques to circumvent these problems and enhance the methodology
(see above links).
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