Smoothed Particle Hydrodynamics
Animations from SPH on front page Periodic Boundary Conditions
Click on video and takes to Smoothed Particle Hydrodynamics page
Link from Current Research section> Smoothed Particle Hydrodynamics
Periodic Boundary Condition Simulations
In this model a fluid is initially held in a square configuration along a sloped ramp with
open boundaries on both sides. At the the first time step the fluid is allow to flow outward due to
the force of gravity and begins to flow down the ramp. Once the fluid particles meet the boundary
edge on the right they cross over to the left side of the ramp. During the first few time steps the
fluid quickly moves to fill the void on the upper left hand side and crashes with slower moving
particles creating a significant splashing effect and the formation of a standing wave. Throughout
the simulation this standing wave begins to die out as the flow approaches a state of equilibrium.
Title: Exploring the method of smoothed particle hydrodynamics (SPH) and its application to
icebergcapsize dynamics
Lynn Kaluzienski, 9/20/2015, University of Maine
Analytical solutions for problems in fluid dynamics are unavailable for most real world
flows. The method of Smoothed Particle Hydrodynamics (SPH) was initially developed for
astrophysical problems and has since been used to formulate approximate solutions for equations
in fluid dynamics, chiefly the Navier Stokes solution for a weakly compressible fluid. SPH takes
the innovative approach of replacing a fluid with an array of particles and solving the Navier
Stokes equation on a particle by particle basis. A smoothing function is applied to each individual
particle to determine the influence of its neighbors within a certain radius giving more weight to
nearby particles. SPH is naturally a meshfree Lagrangian method, providing several benefits over
former gridbased techniques in capturing surface accelerations and removing the need of tracking
fluid boundaries. One difficulty with the SPH method is the need for a large quantity of particles to
achieve the same precision as a gridbased approach. However, recent improvements in
computational power such as the widespread use of graphic processing units (GPUs) have made
SPH implementation feasible and computationally inexpensive. Several open source codes, such as
DualSPHysics, make high resolution SPH simulations easily achievable on computers with
multiple GPU processing units. Depending on complexity, several hundred thousand particle
simulations can be achieved on the order of minutes to hours on a desktop computer. Largerscale
models with millions to even billions of particles can be efficiently computed on supercomputers.
The University of Maine SECS Numerical Laboratory currently has SPH simulations running on
multiple GPUs. In addition, our collaboration with the Advanced Computing Group at Umaine will
allow us to run increasingly complex and higher resolution simulations on one of their
supercomputers in the near future.
Supporting Literature: Crespo et al 2015, Monaghan 2012
Link> Supporting Animations
Each of these representations was exported from Paraview, a powerful visualization tool that stores
all output parameters (pressure, density, velocity, acceleration, vorticity, ID number) for each
particle at every time step.
Dambreak Simulation
In this model a fluid is initially held in a block configuration. At the first time step the fluid is
allowed to flow out due to the force of gravity. As if flows outward it crashes into a rectangular
block and interacts with the boundary walls. The color of each fluid particle corresponds to its
velocity magnitude (m/s) at each time step.
Initial Velocity Simulation
In this model two fluids with spherical and square configurations are given initial velocities. As
they collide with the square surface in the center they interact within a boxed boundary. The color
of each fluid particle corresponds to its velocity magnitude (m/s) at each time step.
WaveMaker Simulation
In this model an oscillating piston creates wave within a fluid. The color of each fluid particle
corresponds to its ID number, thereby illustrating the effect of mixing throughout the simulation.
Link> Introductory SPH Icebergcapsize Simulations
Wave Tank Experiment Simulation
In this model an oscillation piston creates waves within a 250 cm x 50 cm x 50 cm tank. A solid
block of 900 kg/m^3 density floats on one side of the tank and capsizes under the influence of the
standing waves.The color of each fluid particle corresponds to its velocity magnitude (m/s) at each
time step.
Iceberg Closeup
In this view the motion of the particles at the boundary of the model iceberg are shown. The color
of each solid particle corresponds to its acceleration magnitude (m/s^2) at each time step.
