(El Método de Hidrodinámica de Partículas Suavizada)

Desarrollo de un Modelo de Oleajes Para Ingeniería de Costas
(El Método de Hidrodinámica de Partículas Suavizada)
Robert A. Dalrymple, Johns Hopkins University
Moncho Gómez Gesteira, Benedict Rogers, Shan Zuo,
Muthu Narayanaswamy, Alex Crespo, Rozita J. Farahani, Alexis Hérault,
Giuseppe Bilotta, Eugenio Rustico, Brian Lindberg, Munan Xu,
Zhangping Wei
SPH and Nearshore Waves
First free surface flow application
of SPH
Monaghan (1994)
4552 particles
My first application:
Dalrymple, R.A. and O. Knio, SPH
Modelling of Water Waves, Proc.
Coastal Dynamics 2001
At the end of the simulation, the water boiled!
Waves on Beach (Wave Tank)
GPUSPH: visualized by Templeton Automation – 2.8 M particles
Smoothed Particle Hydrodynamics for
a weakly compressible fluid
Model nodes are irregularly spaced particles, each
with mass,
Nodes move with fluid: mesh-free Lagrangian method
Numerical Basis of
Smoothed Particle Hydrodynamics
SPH is based on weighted interpolation:
Kernel Requirements (Monaghan)
Monotonically decreasing with distance |s-x|
Symmetric with distance
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Green water
overtopping
of a deck
Gómez-Gesteira et al., 2005
2-D SPH-SPS
Weakly Plunging Breaking Wave
∆x = 0.0045m 97000 particles slope = 1/13.5 T = 1.4s, Dalrymple and Rogers, 2006
SPHysics:
August 1, 2007
Release of open source code: http://www.sphysics.org
Version 2.0 released Jan 2010
CPU vs GPU
Go, Gamers!
Demand more!
Objectives
Study breaking waves with SPH
Examine nearshore processes with SPH
Explore massively parallel GPUs with SPH
Nvidia Tesla K20
2880 cores!
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Parallel computation is
performed on graphic cards
(GPUs) of computers using
CUDA
Displays real
time results
(UDP Writer)
ATHOS Consortium
Now Open-Source
www.gpusph.org
www.gpusph.org
(Massive) Particle Tracking at Tank Midline
SWL
(and Floating Object)
Mean wave-induced tank circulation being set up.
Note wave setup on beach
SPH for waves and wave-induced currents
Drønen (2004) rip current test: bathymetry
Wavemaker to the right
Drønen Wave Tank Experiment
Wave Phenomena over Shoal/Channel
GPUSPH results
Wave Setup
Depth and Period-Averaged Eulerian
Velocity/Vorticity/Trajectories
wave direction
GPUSPH simulates mean wave-induced quantities
Closed circulation patterns: MacMahan et al., Mar. Geol. (2010)
Intersecting Wave Trains
Note nonlinear waves in
shallow water
Intersecting Waves and Rip Current
Obliquely descending eddies
(Nadaoka et al., 1989)
What causes these eddies?
Horizontal rollers—> eddies?
LES models:
Christensen et al. (2002)
Watanabe et al (2005)
Use a b
Only one wave, therefore the wave breaking process can be
investigated without pre-existing turbulence as in the case of
periodic waves.
Further, a solitary wave is a first approximation to a
tsunami.
Wave height = 0.22 m
Numerical
Experimental (Ting, 2006)
Wave height=
0.22 m
Water depth at
the
wavemaker=
0.3 m
Initial Particle
Spacing = 0.007
m
Number of
particles =
about 7 million
Number of
GPU =1
Color scaled on velocity
Vortex structures under the
broken spilling solitary wave
The wave moves forward
and leaves the vortex
structures behind
Vortex structures are
detected using
method
Organized coherent
structures are observed in
the form of reversed
horseshoe structures
Vorticity and
turbulent velocities
t=3.49s
t=3.69s
t=3.89s
t=4.09s
t=4.29s
The scale of
reversed horseshoe
structures on order
of the wave height
t=4.49s
t=4.69s
t=4.89s
t=5.09s
t=5.29s
Development of reversed
horseshoe structures
In a wave-following
frame, the fluid
particles under the
wave surface travel in
–x direction
The gradient of velocity under the
wave initiates the reversed
horseshoe from the portions of
the spanwise roller where the
curvature is high.
Development of a reversed horseshoe in a wave-following frame
The development of the reversed
horseshoe is analogous to the
development of a horseshoe in a
wall-bounded shear flow
Development of a horseshoe in a wall-bounded shear flow
Generation of Subharmonic Edge Waves
Simulating CCOB IHCantabria, ANIMO project (Giovanni Coco)
Overhead view: Munan Xu calculation; colors show velocity magnitude
1:5 Beach; T=3.6 s
Wavemaker
Rocket Science: Orion Capsule
Splash-down
33
Brian Lindberg calculation
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Brian Lindberg calculation
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Stable Landing (blue) as function attack
angle and Vx and Vy
But what about waves?
An amazing breaking wave feature
to test model
Photo from
under the
wave
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Conclusions
Smoothed Particle Hydrodynamics simulates waves well:
refraction, diffraction, shoaling, wave-induced currents
The GPUSPH model is appropriate for coastal problems
Obliquely descending eddies are actually horseshoe vortices.
GPUSPH models the three-wave resonance of edge waves
Thanks to the:
ATHOS Consortium