Difference between revisions of "Smoothed Particle Hydrodynamics"

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! style="width:500px" | 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.
 
! style="width:500px" | 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.
 
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! style="width:500px" | 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.
 
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[[SPH Supporting Animations|Supporting Animations]]
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'''[[SPH Supporting Animations|Supporting Animations]]'''
 
 
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.
 

Revision as of 18:02, 30 September 2015

Exploring the method of smoothed particle hydrodynamics (SPH) and its application to iceberg­ capsize 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.


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.

Supporting Animations