Record Details
Waves on unsteady currents
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Waves on unsteady currents |
| Names |
Haller, Merrick C.
(creator) Ozkan-Hollar, Tuba (creator) |
| Date Issued | 2007-12-03 (iso8601) |
| Note | Article appears in Physics of Fluids (http://pof.aip.org/) and is copyrighted by American Institute of Physics (http://www.aip.org/). |
| Abstract | Models for surface gravity wave propagation in the presence of currents often assume the current field to be quasi-stationary, which implies that the absolute wave frequency is time invariant. However, in the presence of unsteady currents or time-varying water depth, linear wave theory predicts a time variation of the absolute wave frequency (and wavenumber). Herein, observations of wave frequency modulations from a large-scale laboratory experiment are presented. In this case, the modulations are caused by both unsteady depths and unsteady currents due to the presence of low-frequency standing waves. These new observations allow a unique and detailed verification of the theoretical predictions regarding variations in the absolute wave frequency. In addition, analytic solutions for the variations in frequency and wave height induced by the unsteady medium are found through a perturbation analysis. These solutions clarify the dependency of the wave frequency/wave height modulations on the characteristics of the unsteady medium. We also find that analytic solutions for simplified basin configurations provide an order of magnitude estimate of the expected frequency modulation effect. Finally, the importance of this phenomenon in natural situations is discussed. |
| Genre | Article |
| Identifier | Haller, M. C., & Özkan-Haller, H. T. (2007). Waves on unsteady currents [Electronic version]. Physics of Fluids, 19(12). |
