On the modeling of wave-enhanced turbulence nearshore. (July 2016)

• Record Type: Journal Article
• Authors: Moghimi, Saeed; Thomson, Jim; Özkan-Haller, Tuba; Umlauf, Lars; Zippel, Seth
• Is Part Of: Ocean modelling. Volume 103(2016:Jul.)
• Page Start: 118
• Page End: 132
• Publication Date: 2016-07
• Subjects: Turbulence modeling -- Wave modeling -- Turbulence dissipation rate -- One-dimensional vertical -- Wave–current interaction -- Wave–ocean energy exchange; Oceanography -- Periodicals; Océanographie -- Périodiques; Oceanography; Periodicals; 551.46
• DOI: 10.1016/j.ocemod.2015.11.004
• Languages: English
• ISSNs: 1463-5003

Abstract

Highlights: Injection of turbulence by breaking waves. Application of two-equation turbulence closure models. Model validation against turbulent dissipation rate observations. Comparing wind friction velocity and wave model surface dissipation. Investigating wave enhanced turbulence inside water column. Abstract: A high resolution k – ω two-equation turbulence closure model, including surface wave forcing was employed to fully resolve turbulence dissipation rate profiles close to the ocean surface. Model results were compared with observations from Surface Wave Instrument Floats with Tracking (SWIFTs) in the nearshore region at New River Inlet, North Carolina USA, in June 2012. A sensitivity analysis for different physical parameters and wave and turbulence formulations was performed. The flux of turbulent kinetic energy (TKE) prescribed by wave dissipation from a numerical wave model was compared with the conventional prescription using the wind friction velocity. A surface roughness length of 0.6 times the significant wave height was proposed, and the flux of TKE was applied at a distance below the mean sea surface that is half of this roughness length. The wave enhanced layer had a total depth that is almost three times the significant wave height. In this layer the non-dimensionalized Terray scaling with power of − 1.8 (instead of − 2 ) was applicable.