چكيده به لاتين
Abstract:
In coastal regions, physical phenomena such as wave breaking, triad wave-wave interaction, wave run-up and etc. affect the wave spectrum. Wave energy dissipation due to wave-mud interaction is one of these processes. Due to wave propagation and its imposed load on the muddy bed, a fraction of mud layer starts to mobilize. It indicates that some work is done by wave, and the wave height decreases.
In general, the wave directional spectrum in deep water and a wave model which includes wave-mud interaction can provide the wave spectrum in shallow waters. Hense, it can be employed to estimate the energy extracted from waves in coastal areas which is useful in coastal zone management, shore protection and erosion regimes.
Two important characteristics of viscoelastic mud are viscous property which results to wave dissipation, and elastic one which provides resilience character. There are several methods to estimate mud-induced wave dissipation. The performance of implemented viscoelastic models were verified against analytical solution and viscous formulations for simple one-dimensional propagation cases. Stationary and non-stationary test cases in Surinam coast and Atchafalaya shelf showed that the inclusion of the mud-wave interaction term in the third-generation wave models enhances the model performance in real applications. A high value of mud viscosity (of the order of 0.1 m2/s) was required in both field cases to remedy model overestimation at high frequency range of the wave spectrum. The use of frequency dependent mud viscosity value improved the performance of model, especially in the frequency range of 0.2-0.35 Hz in the wave spectrum. In addition, the mud-wave interaction might affect the high frequency part of the spectrum, and this part of the wave spectrum is also affected by energy transfer from wind to waves, even for the fetch lengths of the order of 10 km. It is shown that ignoring wind input term in such cases might result in different values for parameters of mud layer from inverse modeling procedure. Unlike viscous models for wave-mud interaction, the inverse modeling results to a set of mud parameters with almost the same performance when viscoelastic model is used. It provides opportunity to select realistic mud parameters which are in more agreement with in situ measurements.
Keywords: mud, wave dissipation, wave-mud interaction, viscoelastic model, Atchafalaya, Surinam
