Begeleidingscommissie · Begeleidingscommissie Schaalmodelproeven voor de impact van golven op een...
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Begeleidingscommissie
Schaalmodelproeven voor de impact van golven op een
zeedijk
Activiteit 2 – Vincent GRUWEZ
30 mei 2018 – KUL, Campus Brugge
Storm wall
© Vincent Gruwez (2016)
© René Billiau (2013)
ht
Hm0,o ; Tm-1,0,o
Hofland et al. (2017)
Foreshore slope range Belgian coast: 1/20 – 1/90
Hm0,t ; Tm-1,0,t
© Vincent Gruwez (2017)
© Vincent Gruwez (2017)
Numerical modelling
Experimental modelling
Field measurements
© Vincent Gruwez (2017)
Foreshore slope range Belgian coast: 1/20 – 1/90
2D Experimental modelling – Overview
High spatial resolution
of surface elevationsWave
overtopping
Wave forces
2D Experimental modelling – Model setup
Slope 1/20 – Scale 1:25
Slope 1/50 – Scale 1:25
Slope 1/50 – Scale 1:35
Slope 1/80 – Scale 1:35
RS11
First results (2D) – Wave transformation over the foreshore
First results (2D) – Wave overtopping
Based on Van Gent (1999), recalibrated and extended with equivalent slope concept by Altomare et al. (2016):
First results (2D) – Spectral wave period Tm-1,0 at the dike toe
Hofland et al. (2017):
First results (2D) – Wave impact forces
Load cell at wallLoad cell at window
Numerical modelling
Experimental modelling
Field measurements
3D Experimental modelling – Motivation
Long-crested waves Short-crested waves
3D Experimental modelling – Motivation
Long-crested waves
(2D wave flume)
Short-crested waves
(3D wave basin)
3D Experimental modelling – Motivation
at WTR
Overestimation of energy
at low-frequencies in 2D
modelling
Validated by in-situ
measurements(Ostend, BE)
3D Experimental modelling – Overview
Model setup
Wave
overtopping
Wave forces
Long-crested waves Short-crested waves
First results (3D) – Wave overtopping
43% decrease
Long-crested waves Short-crested waves
First results (3D) – Wave impact forces
F10%=6.9 N/m
F10%=4.3 N/m
•Experimental modelling was conducted to support the development of new (empirical, numerical) tools to aid the design of sea dikes with a very shallow foreshore
•Focus on wave transformation, wave overtopping and wave impact forces
Conclusions
•2D tests (UGent):
‣ HSR tests show a significant increase of long wave energy close to the dike
‣ The foreshore slope value has a clear influence:
The accuracy of the prediction formula for wave overtopping is sensitive to the foreshore slope value for high freeboard values
The prediction formula for Tm-1,0,t will be improved for the case of steeper foreshore slopes (for slopes 1/20 and 1/35)
‣ Illustration of variability of load cell measurements over the width of the flume
Conclusions
•3D tests (FHR):
‣ Short-crested waves cause lower wave height long waves at the sea dike:
Decreased amount of overtopping
Decreased wave impact forces
‣ Short-crestedness important and not to be neglected
Conclusions
Thank you for your attention!