A representative underlying scale for spectrally resolved energy dissipation in surface breaking waves
In the Duncan-Phillips framework for breaking wave energy dissipation, the underlying scale at which dissipation occurs is commonly inferred from a measure of the breaking-wave phase speed, most often taken as the spectrally informed phase speed C s , the local phase speed at incipient breaking C b...
| Autores: | , , , |
|---|---|
| Tipo de recurso: | artículo |
| Fecha de publicación: | 2026 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:dnet:upcommonspor::fa7b917d3951ce697e6da6999b9e1969 |
| Acceso en línea: | https://hdl.handle.net/2117/462447 https://dx.doi.org/10.1029/2025JC023904 |
| Access Level: | acceso abierto |
| Palabra clave: | Wave breaking Surface gravity waves Experimental wave mechanics Energy dissipation Spectral wave analysis Àrees temàtiques de la UPC::Enginyeria civil::Geologia::Oceanografia |
| Sumario: | In the Duncan-Phillips framework for breaking wave energy dissipation, the underlying scale at which dissipation occurs is commonly inferred from a measure of the breaking-wave phase speed, most often taken as the spectrally informed phase speed C s , the local phase speed at incipient breaking C b , and the whitecap advancing speed C w . However, energy loss occurs across a finite spectral band, and the link between these single-speed measures and the representative dissipation scale requires further investigation. Using unidirectional laboratory wave groups, we identify the spectral range over which energy dissipation occurs in breaking waves ( ˜ 0.95 f p – 1.8 f p , with f p the peak frequency). From this, we define an energy-dissipation-weighted-frequency f ¿ and a corresponding phase speed C ¿ (via the linear dispersion relation), which characterize the effective scale at which energy is lost from the wave group. We show that for the waves studied here this dissipative scale is systematically smaller than local and spectral speed measures, with C ¿ ¿ O 0.95 C b ¿ O 0.87 C s . When inferred from whitecap-based measures (most commonly implemented in the field from optical remote sensing), C ¿ corresponds to approximately O ( 0.91 – 0.96 ) of the time-averaged whitecap advancing speed, depending on how the whitecap speed is defined. Taken together, these correlations indicate that the commonly used measures C s , C b , and whitecap-based speeds are broadly connected, with our quantitative analysis further demonstrating that their relationships are modulated by the strength of breaking. Overall, our study provides a clearer physical basis for identifying dissipation scales in broadband breaking waves and helps reconcile existing laboratory, numerical, and field-based approaches. |
|---|