Details
| Original language | English |
|---|---|
| Pages (from-to) | 15-31 |
| Number of pages | 17 |
| Journal | Coastal engineering |
| Volume | 93 |
| Early online date | 1 Aug 2014 |
| Publication status | Published - Nov 2014 |
Abstract
A proper design of offshore and coastal structures requires further knowledge about extreme wave events. Such waves are highly nonlinear and may occur unexpectedly due to diverse reasons. One of these reasons is wave-wave interaction and the wave focusing technique represents one option to generate extreme wave events in the laboratory. The underlying mechanism is the superimposition and phasing of wave components at a predefined location. To date, most of the existing methods to propagate target wave profile backwards to the position of the wave generator apply linear wave theory. The problem is that the generated waves with different frequencies generate new components which do not satisfy the linear dispersion relation. As a result, small changes in the wave board control signal generally induce large and random shifts in the resulting focused wave. This means that iterations are necessary to get the required wave profile at the correct position in the flume. In this study, a Self Correcting Method (SCM) is applied to optimize the control signal of the wave maker in a Numerical Wave Tank (NWT). The nonlinearities are included in the control signal and accurate wave focusing is obtained irrespective of the prevailing seabed topography (horizontal or sloping) and type of structure (reflective or absorbing). The performance of the proposed SCM is numerically investigated for a wide variety of scenarios and validated by scale model tests in the Large Wave Flume (Großer Wellen Kanal, GWK), Hannover, Germany. Moreover, the application of the proposed SCM in the Numerical Wave Tank to generate a tsunami at a predefined position and the comparison of the results with the time series recorded in the Pago Pago harbour (Samoa) is very encouraging. The strengths and limitations of the proposed SCM are discussed, including the potential for further developments.
Keywords
- Extreme waves, Nonlinear waves, Numerical wave tank, Self correcting method, Tsunami generation, Wave focusing
ASJC Scopus subject areas
- Environmental Science(all)
- Environmental Engineering
- Engineering(all)
- Ocean Engineering
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In: Coastal engineering, Vol. 93, 11.2014, p. 15-31.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Extreme wave generation using self correcting method - revisited
AU - Fernández, H.
AU - Sriram, V.
AU - Schimmels, S.
AU - Oumeraci, H.
N1 - Funding Information: This research is funded by EC through the seventh framework programme, particularly the work presented here belongs to the HydralabIV project within the joint research activity HyReS (Hydraulic Response of Structures), Contract no. 261520. The authors are grateful to the WAVESLAM project, a consortium coordinated by the University of Stavanger, Norway (Prof. Ove T. Gudmestad) and the Norwegian University of Science and Technology, Trondheim, Norway (Prof. Øivind A. Arntsen). The authors would also like to acknowledge Dr. Ira Didenkulova and Dr. Vasily Titov for gathering the data of the Samoa 2009 Tsunami. Dr. Sriram is grateful to Alexander von Humboldt foundation, Germany and would like to acknowledge Prof. K-F., Daemrich for many fruitful discussion during his stay at Franzius Institute, Leibniz Universität Hannover, Hannover.
PY - 2014/11
Y1 - 2014/11
N2 - A proper design of offshore and coastal structures requires further knowledge about extreme wave events. Such waves are highly nonlinear and may occur unexpectedly due to diverse reasons. One of these reasons is wave-wave interaction and the wave focusing technique represents one option to generate extreme wave events in the laboratory. The underlying mechanism is the superimposition and phasing of wave components at a predefined location. To date, most of the existing methods to propagate target wave profile backwards to the position of the wave generator apply linear wave theory. The problem is that the generated waves with different frequencies generate new components which do not satisfy the linear dispersion relation. As a result, small changes in the wave board control signal generally induce large and random shifts in the resulting focused wave. This means that iterations are necessary to get the required wave profile at the correct position in the flume. In this study, a Self Correcting Method (SCM) is applied to optimize the control signal of the wave maker in a Numerical Wave Tank (NWT). The nonlinearities are included in the control signal and accurate wave focusing is obtained irrespective of the prevailing seabed topography (horizontal or sloping) and type of structure (reflective or absorbing). The performance of the proposed SCM is numerically investigated for a wide variety of scenarios and validated by scale model tests in the Large Wave Flume (Großer Wellen Kanal, GWK), Hannover, Germany. Moreover, the application of the proposed SCM in the Numerical Wave Tank to generate a tsunami at a predefined position and the comparison of the results with the time series recorded in the Pago Pago harbour (Samoa) is very encouraging. The strengths and limitations of the proposed SCM are discussed, including the potential for further developments.
AB - A proper design of offshore and coastal structures requires further knowledge about extreme wave events. Such waves are highly nonlinear and may occur unexpectedly due to diverse reasons. One of these reasons is wave-wave interaction and the wave focusing technique represents one option to generate extreme wave events in the laboratory. The underlying mechanism is the superimposition and phasing of wave components at a predefined location. To date, most of the existing methods to propagate target wave profile backwards to the position of the wave generator apply linear wave theory. The problem is that the generated waves with different frequencies generate new components which do not satisfy the linear dispersion relation. As a result, small changes in the wave board control signal generally induce large and random shifts in the resulting focused wave. This means that iterations are necessary to get the required wave profile at the correct position in the flume. In this study, a Self Correcting Method (SCM) is applied to optimize the control signal of the wave maker in a Numerical Wave Tank (NWT). The nonlinearities are included in the control signal and accurate wave focusing is obtained irrespective of the prevailing seabed topography (horizontal or sloping) and type of structure (reflective or absorbing). The performance of the proposed SCM is numerically investigated for a wide variety of scenarios and validated by scale model tests in the Large Wave Flume (Großer Wellen Kanal, GWK), Hannover, Germany. Moreover, the application of the proposed SCM in the Numerical Wave Tank to generate a tsunami at a predefined position and the comparison of the results with the time series recorded in the Pago Pago harbour (Samoa) is very encouraging. The strengths and limitations of the proposed SCM are discussed, including the potential for further developments.
KW - Extreme waves
KW - Nonlinear waves
KW - Numerical wave tank
KW - Self correcting method
KW - Tsunami generation
KW - Wave focusing
UR - http://www.scopus.com/inward/record.url?scp=84905384050&partnerID=8YFLogxK
U2 - 10.1016/j.coastaleng.2014.07.003
DO - 10.1016/j.coastaleng.2014.07.003
M3 - Article
AN - SCOPUS:84905384050
VL - 93
SP - 15
EP - 31
JO - Coastal engineering
JF - Coastal engineering
SN - 0378-3839
ER -