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 6
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! 11
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 (and Floating Object) SWL 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 The scale of reversed horseshoe structures on order of the wave height t=4.49s t=3.69s t=4.69s t=3.89s t=4.89s t=4.09s t=5.09s t=4.29s t=5.29s
In a wave-following frame, the fluid particles under the wave surface travel in x direction Development of reversed horseshoe structures Development of a reversed horseshoe in a wave-following frame 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 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 34
Brian Lindberg calculation 35
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 38
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