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Long-period waves propagating inside harbours can lead to the generation of seiche that can affect and significantly disrupt port operations. This study is based on the analysis of a multi-years tide gauge database provided by the sea-level observation network (RONIM). It aims to propose simple models to compute seiche amplitudes at a series of Fre...
Citations
... Some authors aimed at determining their generation and amplification processes (Mei and Agnon, 1989;Sammartino et al., 2014;Karathanasi et al., 2020;Bellotti, 2020), whereas others conducted research on how to reduce the amplitudes of infragravity waves in ports: Geraldton, Australia, (van Dongeren et al., 2016), Mukho, Korea, (Kwak et al., 2020) or in NGqura, South Africa (Troch et al., 2020b). Many studies focused on long wave prediction (Diaz-Hernandez et al., 2015;André et al., 2021). Moored ship motions and their relationship with infragravity waves have been analyzed from different perspectives. ...
The coupling of low-frequency oscillatory modes of a harbor with horizontal motions of moored ships can amplify the latter, causing operational and safety problems. The objectives of this study were to analyze infra-gravity waves and their effect on moored ship motions; to validate the Wavelet Transform Analysis (WTA) method for studying port-ship resonance in the Outer Port of Punta Langosteira, Spain; and to study the climatic forcing of downtimes. The excited resonant modes of the basin (102 and 132 s) were determined using a numerical model and high-frequency water level measurements at different points of the harbor. Yaw and sway motions of three bulk carriers were analyzed in the frequency-time domain using WTA. The results showed that the oscillation periods of the studied vessel motions are directly related to the water depth to vessel draft ratio. In addition, when the wind speeds exceeds 20 km/h, the ship moves away from the fenders, which lead to a lengthening of these periods. Based on our findings, yaw may induce oscillations of the same period in sway. Additionally, operational thresholds were proposed based on outer and inner waves data that will lead to optimize ship stays, avoiding downtimes, and to advance the safety of loading and unloading operations.
... To the best of the authors' knowledge, there exist many investigations on wave forecasting inside harbors by combining spectral wave models for the offshore waves and several fast methods for the waves inside the harbors. The fast methods include the linear interpolation method (Choi et al., 2019), empirical formula (André et al., 2021), and others. Wave forecasting method based on spectral wave models and ANN models, considering both short waves and LF waves, has not been developed. ...
An artificial neural network (ANN) model was recently developed to rapidly estimate the wave heights inside a harbor using offshore bulk wave parameters (i.e., wave height, period, and direction). This study combines the spectral wave model WAVEWATCH III (WW3) with the ANN model to realize rapid and accurate forecasting. The wave heights are estimated by the ANN model using the wave parameters from WW3. The ANN-estimated results are successfully verified against the observation, proving the reliability of the WW3-ANN approach. An effort is further devoted to assessing the performance accuracy of the ANN driven by the input from the WW3 models built on different spatial scales and by the input from various wave systems (i.e., mixed waves and swell). Moreover, the influence of the output locations of WW3 on the estimation is examined. The discrepancies in the wave parameters at different offshore points show an insignificant effect on the ANN-estimated results. Finally, the sensitivity analysis of the ANN model to the input variables is explained. The procedures for developing the ANN model and for the sensitivity analysis can be implemented in any harbor of interest.
Free access link to the full text (until the 15th October): https://authors.elsevier.com/a/1deTK1M2DVCpD9
Harbour resonance and its contribution to wave overtopping are examined for a small irregular–shaped harbour in the eastern Mediterranean. Offshore wave measurements are used to determine the incident wave conditions during storm events. Resonant periods of the harbour basin are identified through in situ measurements at four different deployment locations during multiple storm events. Numerical simulations using a Boussinesq–type model and an idealised offshore spectrum yielded similar resonant frequencies to the field measurements and allowed us to visualise the corresponding resonant modes. Wave overtopping along the vertical docks of the harbour is inferred by combining numerical time series of free surface elevation with EurOtop formulae. Two approaches to estimate wave overtopping rates are examined and compared: a novel approach considering wave energy in the sea-swell frequency range and varying the freeboard through time series in the infragravity frequency range, and the conventional method that considers spectral parameters along the entire frequency range. The novel approach provides an estimate for the contribution of harbour resonance to wave overtopping considering that infragravity wave energy inside the basin is mainly resonance–driven.
