Difference between revisions of "Smoothed Particle Hydrodynamics"

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'''Exploring the method of smoothed particle hydrodynamics (SPH) and its application to iceberg­ capsize dynamics'''
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== Want to use Smoothed Particle Hydrodynamics (SPH) for your Earth Science Investigation? ==
  
''Lynn Kaluzienski, 9/20/2015, University of Maine''
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Please refer to: [[DualSPHysics Guidelines for Earth Scientists]]
 +
 
 +
== Exploring the Dynamics and Kinematics of Rivers with Smoothed Particle Hydrodynamics (SPH) ==
  
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.
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''[[User:Nick | Nick Richmond]], University of Maine''
  
{{#ev:youtube|CT239kMKBag}}
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Smoothed Particle Hydrodynamics (SPH) provides a meshless solution for fluid mechanics in three dimensions. Unlike traditional computational fluid dynamics methods, SPH is capable of handling violent flows with complex surface dynamics, which makes SPH a useful tool for investigating the motions and forces associated with flow in Earth Systems. So far, I've used SPH for two main projects:
 +
* [[Bedrock Channel Evolution | '''3D bedrock channel evolution with Smoothed Particle Hydrodynamics coupled to a Finite Element Earth''']]
 +
* [[Penobscot River Hydraulics | '''Post-dam removal river hydraulics and the influence of derelict industrial logging infrastructure on modern aquatic habitat''']]
  
 
{| class="wikitable"
 
{| class="wikitable"
 
|-
 
|-
! 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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! style="width:330px" | Click on the animated gif to learn more about how we use SPH and Finite Element Analysis to study bedrock channel evolution.
! {{#ev:youtube|rAUqGTGb57k}}
+
! style="width:330px" | Click on the animated gif to learn more about how we use SPH to study the effects of relict logging structures on aquatic habitat in Maine's Penobscot River.
 +
|-
 +
| [[File:KnickpointMeanderVel01.gif|link=Bedrock Channel Evolution|700px]]
 +
| [[File:BoomIsland01.gif|link=Penobscot River Hydraulics|700px]]
 
|-
 
|-
 +
| style="width:330px" | Here, water flows through an eroded knickpoint with several upstream meanders which develop as a result of preferential erosion of weak material.
 +
| style="width:330px" | Here, water flows around an idealized version of a relict logging structure known as a "boom island."
 +
|}
  
{{#ev:youtube|B9TRacHKikE}}
 
{{#ev:youtube|n7KEnqLg1NE}}
 
{{#ev:youtube|r6vm1F5vpmM}}
 
{{#ev:youtube|BiHVYMhOg-M}}
 
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
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== Exploring the method of smoothed particle hydrodynamics (SPH) and its application to iceberg­ capsize dynamics ==
  
­Periodic Boundary Condition Simulations
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''Lynn Kaluzienski, 9/20/2015, University of Maine''
  
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
+
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.
  
the force of gravity and begins to flow down the ramp. Once the fluid particles meet the boundary
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'''Supporting Literature: Crespo et al 2015, Monaghan 2012'''
  
edge on the right they cross over to the left side of the ramp. During the first few time steps the
+
{| class="wikitable"
 +
|-
 +
! 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.
  
fluid quickly moves to fill the void on the upper left hand side and crashes with slower moving
+
Credits: [http://www.dual.sphysics.org DualSPHysics]
  
particles creating a significant splashing effect and the formation of a standing wave. Throughout
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'''[[SPH Supporting Animations|Supporting Animations]]'''
  
the simulation this standing wave begins to die out as the flow approaches a state of equilibrium.
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'''[[Introductory SPH Iceberg­-capsize Simulations]]'''
 
+
! {{#ev:youtube|CT239kMKBag}}
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
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'''For DualSPHysics users operating in the UMaine SECS Numerical Modeling Laboratory:'''
  
of each solid particle corresponds to its acceleration magnitude (m/s^2) at each time step.
+
Please see the [http://130.111.222.81/mediawiki-1.19.23/images/b/ba/DualSPH_User_Guide.pdf DualSPHysics User Guide] for a basic program tutorial.

Latest revision as of 15:59, 28 March 2019

Want to use Smoothed Particle Hydrodynamics (SPH) for your Earth Science Investigation?

Please refer to: DualSPHysics Guidelines for Earth Scientists

Exploring the Dynamics and Kinematics of Rivers with Smoothed Particle Hydrodynamics (SPH)

Nick Richmond, University of Maine

Smoothed Particle Hydrodynamics (SPH) provides a meshless solution for fluid mechanics in three dimensions. Unlike traditional computational fluid dynamics methods, SPH is capable of handling violent flows with complex surface dynamics, which makes SPH a useful tool for investigating the motions and forces associated with flow in Earth Systems. So far, I've used SPH for two main projects:

Click on the animated gif to learn more about how we use SPH and Finite Element Analysis to study bedrock channel evolution. Click on the animated gif to learn more about how we use SPH to study the effects of relict logging structures on aquatic habitat in Maine's Penobscot River.
KnickpointMeanderVel01.gif BoomIsland01.gif
Here, water flows through an eroded knickpoint with several upstream meanders which develop as a result of preferential erosion of weak material. Here, water flows around an idealized version of a relict logging structure known as a "boom island."


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.

Supporting Literature: Crespo et al 2015, Monaghan 2012

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.

Credits: DualSPHysics

Supporting Animations

Introductory SPH Iceberg­-capsize Simulations







For DualSPHysics users operating in the UMaine SECS Numerical Modeling Laboratory:

Please see the DualSPHysics User Guide for a basic program tutorial.