Desarrollo de un Modelo de Oleajes Para Ingeniería de Costas (El Método de Hidrodinámica de Partículas Suavizada)

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1 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

2 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!

3 Waves on Beach (Wave Tank) GPUSPH: visualized by Templeton Automation 2.8 M particles

4 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

5 Numerical Basis of Smoothed Particle Hydrodynamics SPH is based on weighted interpolation:

6 Kernel Requirements (Monaghan) Monotonically decreasing with distance s-x Symmetric with distance 6

7 Green water overtopping of a deck Gómez-Gesteira et al., 2005

2-D SPH-SPS Weakly Plunging Breaking Wave x = 0.

8 2-D SPH-SPS Weakly Plunging Breaking Wave x = m particles slope = 1/13.5 T = 1.4s, Dalrymple and Rogers, 2006

9 SPHysics: August 1, 2007 Release of open source code: Version 2.0 released Jan 2010

10 CPU vs GPU Go, Gamers! Demand more!

11 Objectives Study breaking waves with SPH Examine nearshore processes with SPH Explore massively parallel GPUs with SPH Nvidia Tesla K cores! 11

12 Parallel computation is performed on graphic cards (GPUs) of computers using CUDA Displays real time results (UDP Writer) ATHOS Consortium Now Open-Source

13 (Massive) Particle Tracking at Tank Midline (and Floating Object) SWL Mean wave-induced tank circulation being set up. Note wave setup on beach

14 SPH for waves and wave-induced currents Drønen (2004) rip current test: bathymetry Wavemaker to the right

15 Drønen Wave Tank Experiment

16 Wave Phenomena over Shoal/Channel GPUSPH results Wave Setup

17 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)

18 Intersecting Wave Trains Note nonlinear waves in shallow water

19 Intersecting Waves and Rip Current

20 Obliquely descending eddies (Nadaoka et al., 1989) What causes these eddies? Horizontal rollers > eddies? LES models: Christensen et al. (2002) Watanabe et al (2005)

21 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.

22 Wave height = 0.22 m

23 Numerical Experimental (Ting, 2006)

Wave height= 0.22 m Water depth at the wavemaker= 0.3 m Initial Particle Spacing = 0.

24 Wave height= 0.22 m Water depth at the wavemaker= 0.3 m Initial Particle Spacing = m Number of particles = about 7 million Number of GPU =1 Color scaled on velocity

25 Vortex structures under the broken spilling solitary wave The wave moves forward and leaves the vortex structures behind

26 Vortex structures are detected using method Organized coherent structures are observed in the form of reversed horseshoe structures Vorticity and turbulent velocities

27 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

28 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

29 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

30 Rocket Science: Orion Capsule Splash-down 33

31 Brian Lindberg calculation 34

32 Brian Lindberg calculation 35

33 Stable Landing (blue) as function attack angle and Vx and Vy

34 But what about waves?

35 An amazing breaking wave feature to test model Photo from under the wave 38

$Conclusions Smoothed Particle Hydrodynamics simulates waves well: refraction,$ coastal problems Obliquely descending eddies are actually horseshoe vortices.

coastal problems Obliquely descending eddies are actually horseshoe vortices.

36 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

Turbulent Coherent Structures under Breaking Water Waves

Turbulent Coherent Structures under Breaking Water Waves Rozita Jalali Farahani Civil Engineering Department Johns Hopkins University Baltimore, USA rozita@jhu.edu Robert A. Dalrymple Civil Engineering