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

Desarrollo de un Modelo de Oleajes Para Ingeniería de Costas

(El Método de Hidrodinámica de Partículas Suavizada)

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)

6

Monotonically decreasing with distance |s-x|

Symmetric with distance

Green water

overtopping

of a deck

Gómez-Gesteira et al., 2005

2-D SPH-SPSWeakly Plunging Breaking Wave

∆x = 0.0045m 97000 particles slope = 1/13.5 T = 1.4s, Dalrymple and Rogers, 2006

SPHysics: August 1, 2007Release of open source code: http://www.sphysics.org

Version 2.0 released Jan 2010

CPU vs GPU Go, Gamers!Demand more!

Objectives

11

Study breaking waves with SPH

Examine nearshore processes with SPH

Explore massively parallel GPUs with SPH

Nvidia Tesla K20

2880 cores!

Now Open-Source

www.gpusph.org

Parallel computation is

performed on graphic cards

(GPUs) of computers using

CUDA

Displays real

time results

(UDP Writer)

www.gpusph.org

ATHOS Consortium

(Massive) Particle Tracking at Tank Midline

(and Floating Object)

Mean wave-induced tank circulation being set up.

Note wave setup on beach

SWL

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)

LES models:

Christensen et al. (2002)

Watanabe et al (2005)

What causes these eddies?

Horizontal rollers—> eddies?

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 =1Color scaled on velocity

Vortex structures under the

broken spilling solitary wave

The wave moves forward

and leaves the vortex

structures behind

Vorticity and

turbulent velocities

Vortex structures are

detected using

method

Organized coherent

structures are observed in

the form of reversed

horseshoe structures

t=4.49s

t=4.69s

t=4.89s

t=5.09s

t=5.29s

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

Development of reversed

horseshoe structures

Development of a reversed horseshoe in a wave-following frame

Development of a horseshoe in a wall-bounded shear flow

The gradient of velocity under the

wave initiates the reversed

horseshoe from the portions of

the spanwise roller where the

curvature is high.

The development of the reversed

horseshoe is analogous to the

development of a horseshoe in a

wall-bounded shear flow

In a wave-following

frame, the fluid

particles under the

wave surface travel in

–x direction

Generation of Subharmonic Edge WavesSimulating CCOB IHCantabria, ANIMO project (Giovanni Coco)

Overhead view: Munan Xu calculation; colors show velocity magnitude

Wavemaker

1:5 Beach; T=3.6 s

Rocket Science: Orion Capsule Splash-down

33

34

Brian Lindberg calculation

35

Brian Lindberg calculation

Stable Landing (blue) as function attack

angle and Vx and Vy

But what about waves?

An amazing breaking wave featureto test model

38

Photo from

under the

wave

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