Title
Water-depth identification from free-surface data using the KdV-based nonlinear Fourier transform
Author
de Koster, P.B.J. (TU Delft Team Sander Wahls) 
Brühl, M. (TU Delft Team Sander Wahls)
Wahls, S. (TU Delft Team Sander Wahls)
Date
2022
Abstract
We propose a novel method to determine the average water depth from shallow, weakly nonlinear water waves that are approximated by the Korteweg-de Vries equation. Our identification method only requires free-surface measurements from two wave gauges aligned in the direction of wave propagation. The method we propose is based on comparing solitonic components in wave packets, which are computed using the nonlinear Fourier transform (NFT) (typical time-series data often contains at least some solitonic components, even when these components are not directly visible). When the correct water depth is used for the normalisation of the wave, the solitonic components found by the NFT remain constant as the wave packet propagates, whereas any other water depth will result in solitonic components that do not remain constant. The basic idea is thus to iteratively determine the water depth that leads to a best fit between the solitonic components of time series measurements at two different gauge positions. We present a proof-of-concept on experimental bore data generated in a wave flume, where the identified water depth is within 5% of the measured value.
Subject
Fourier transforms
Water
Waves
Gages
Time series
Wave packets
Flumes
Korteweg-de Vries equation
Water waves
Wave propagation
To reference this document use:
http://resolver.tudelft.nl/uuid:7613d7ef-ca71-4d8d-b8fc-0d7fa367b247
DOI
https://doi.org/10.1115/OMAE2022-78882
Publisher
ASME
Embargo date
2023-07-01
ISBN
978-0-7918-8590-1
Source
Proceedings of the ASME 2022 41th International Conference on Ocean, Offshore and Arctic Engineering (OMAE 2022): Ocean Engineering; Honoring Symposium for Professor Günther F. Clauss on Hydrodynamics and Ocean Engineering, 5B
Event
41th International Conference on Ocean, Offshore and Arctic Engineering, 2022-06-05 → 2022-06-10, Hamburg, Germany
Bibliographical note
Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.
Part of collection
Institutional Repository
Document type
conference paper
Rights
© 2022 P.B.J. de Koster, M. Brühl, S. Wahls