Transcript Wind effect on water level setup

Wind effects on waves propagating to the shore: experimental and numerical investigations
H. Branger (1), L. Grare (1), Ch. Kharif(1,2), P. Lubin (3), S. Glockner (3), P. Robin (1,2) and O. Kimmoun (1,2)
(1) [email protected] - IRPHE/CNRS, Campus Luminy, Case 903, 13009 Marseille, France
Goal:
EGU Vienna-2011 - Meeting
(2) Ecole Centrale Marseille, (ECM), 38 rue Joliot Curie, 13451 Marseille, France; (3) Laboratoire I2M/CNRS, 16 avenue Pey-Berland, 33607 Pessac Cedex, France
Physical and numerical experiments on wave transformation in the surf zone and in the swash zone, with a wind blowing on-shore: wind effects on wave shoaling, wave setup and wave runup
A)
B)
Experimental : ECM wave tank
17m x 0.7m x0.7m, bottom slope 1/15
Regular and Irregular (Jonswap) waves
Tools:
Experimental : IRPHE Wind wave tank
40m x 2.6m x0.9m (water)x1.6m(air) bottom slope 1/30
Regular and Irregular (Jonswap) waves + Wind
 wave gauges, Image processing, laser, anemometer
 run-up, setup, water elevation, celerity, wind speed
(Kimmoun et al, JFM, vol 588, 2007)
 wave gauges, PIV, Image processing
 run-up, setup, water elevation,
phase celerity, velocities
GERRIS numerical code: open source 2-phases
Navier Stokes solver , VOF Method,
adaptive mesh refinement
http://gfs.sourceforge.net/wiki/index.php/Main_Page
Regular waves + Wind
Simulation of ECM + Wind experiment
Experiment / models (GERRIS, LES, Boussinesq)
location of wave extrema (envelope)
Results:
C)
GERRIS numerical code / ECM experiments comparisons
D)
L.E.S I2M Large Eddy Simulation numerical code,
2-phases Navier Stokes Solver, VOF method, subgrid
scale turbulence model, interface tracking method
(Lubin et al, EJM, 2011, doi:10.1016/j.euromechflu.2011.01.001)
Regular waves
Simulation of ECM experiment
Numerical:
GERRIS
E)
ECM Boussinesq numerical code (Bingham et al., Coast.
Eng., 56, 2009 ; Robin et al, Journ Hydro, Nantes, 2011)
+ Wind input model (Jeffreys, Proc R. Soc. Lond, 107, 1925;
Miles, JFM, 3, 1957)
+ Roller breaking model (Shaffer et al,Coast. Eng., 20, 1993) +
Runup model (Lynett et al, Coast. Eng., 46, 2002)
Regular and Irregular (Jonswap) waves + Wind
Simulation of ECM and IRPHE Wind experiments
Boussinesq model / IRPHE experiments
28m from wavemaker, at depth 5cm
/ L.E.S. comparisons
GERRIS
maxima
GERRIS
1)
Experiment/
Model
Comparisons
Mean water level
LES
minima
Experiments
Jonswap waves + Wind : 2D Map of Wave Celerity (IRPHE experiments)
GERRIS numerical simulation of wind over waves moving to the shore
No wind
No wind
2) Wind
effects
U  0 m/ s
  6.7 cm
  1/ 30
U 8 m/s
  16.4 cm
  1/ 30
U  5 m/ s
  9.5 cm
  1/ 30
U  11 m / s
  55 cm
  1/ 30
Velocity
Velocity
Vorticity
Wind: U10=11 m/s
u*=50cm/s, zo=1mm
logarithmic profile
Wind: U10=11 m/s,
u*=50cm/s,zo=1mm
logarithmic profile
Vorticity
Wind effects on Jonswap Waves  Increase of wave celerity, run-up, wave setup, modification of dispersion relationship
c   g  tan( ) , with c  phase speed ,  coefficient,  mean shoreline position,  bottom slope
U=5m/s
U=8m/s
U=6 m/s
maxima
3
15
U=0 m/s
10
U=8m/s
5
0
-12
Conclusions:
U=15m/s
20
-5
-10
time (s)
Wave shoaling
2
25
Setup
U=0m/s
U=5m/s
U=8m/s
U=11m/s
U=15m/s
1
U=0m/s
U=11m/s
30
Wind effects on extrema locations (GERRIS Numerical)
0
Setup
Mean water level (mm)
U=15m/s
Wind effect on wave shoaling (Jonswap) - Experiment
35
Water level (cm)
Water level (cm)
Wind effect on water level setup - Experiment
(Tissier et al, EJM, 2011)
minima
-8
-8
-6
-6
-4
Distance from shore (m)
-4
-2
-2
0
0
2
2
Distance from shore (cm)
Wind blowing towards the shore has a large effect on wave kinematics, shoaling, run-up and water level setup
Numerical Tools under progress : dissipation, sub-grid modelisation, breaking roller and run-up parameterizations for Boussinesq model need to be improved
A very thin numerical spatial discretization is required (Dx < 1mm)
French ANR Grant
HEXECO