Laboratory experiments on time-space conversion of wind waves in deep water

• Published in: Applied ocean research Vol. 111; p. 102656
• Main Authors: Eyhavand-Koohzadi, Amin, Badiei, Peyman
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.06.2021
• Subjects: Deep water waves; Duration- and fetch-limited setups; Fetch-duration conversion equation; Model experimentation; Duration- and fetch-limited setups; Fetch-duration conversion equation; Model experimentation; Deep water waves
• ISSN: 0141-1187; 1879-1549
• DOI: 10.1016/j.apor.2021.102656

•Fetch- and duration-limited wave growth scenarios under steady wind action are accurately investigated in a wind-wave flume.•For each scenario, the energy balance equation is decoupled to examine the portioning of the wind energy between the dominant spectral characteristics of the generated waves.•Fetch-duration conversion equations for wave height and wave period are dissimilar.•Analytical solution of time-space integral is only applicable for wave period. In comparison to the fetch-limited wave regime, the available data for duration-limited growth condition is very limited. Mutual conversion of these wave regimes is of interest and significance in all of the parametric growth functions proposed so far. Therefore, field-based heuristic relationships have been proposed to convert fetch-limited evolution data into duration-limited domain. However, considering the difficulty of collecting field-based duration-limited wave data, the reliability of the proposed equations is quite questionable. The main aim of this study is to provide experimental measurements describing the fetch-duration conversion of the dominant spectral characteristics of the water waves under steady wind action. The measurements of the present experimentations are supported by the analysis of the energy balance equations governing the wind energy expenditure during each wave scenario. The results manifested the co-existence of two different fetch-duration transition domains for each individual wave height and wave period. Analytical solution of the time-space connecting integral resulted in a conversion equation that was in good agreement with that obtained from the experimental data based on equivalent peak period. It is also demonstrated that although the experiments introduced here were carried out at the initial stages of the wave growth, the obtained results were in good agreement with those reported in more developed growth conditions.