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Phase‐Resolved Wave Boundary Layer Dynamics in a Shallow Estuary
Author(s) -
Cowherd Marianne,
Egan Galen,
Monismith Stephen,
Fringer Oliver
Publication year - 2021
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl092251
Subject(s) - boundary layer , turbulence modeling , turbulence , dissipation , mechanics , phase velocity , geology , phase (matter) , boundary layer thickness , physics , computational physics , optics , thermodynamics , quantum mechanics
We present in situ observations of near‐bed velocity profiles with high temporal and spatial resolution from a Nortek Vectrino Profiler deployed in South San Francisco Bay. Using Hilbert analysis, we ensemble‐averaged near‐bed velocity profiles by wave phase and calculated wave phase‐dependent boundary layer thickness for varying wave and current conditions. We also applied mixing length relationships to derive a boundary layer thickness‐based eddy‐viscosity and compared this estimate to one obtained from the k – ɛ turbulence model. From the eddy viscosity estimates, we find that while turbulence responds instantaneously to shear, boundary layer thickness lags by a scaling estimate based on the turbulence response timescale. This analysis provides a method for wave phase decomposition of field‐based velocity profile time series and shows that there is a finite‐time response between turbulence dissipation and boundary layer thickness.