On the Dependency of Bottom Drag and the Eddy Viscosity upon Flow Structure in the Coastal Boundary Layer

Bibliographic Details
Title: On the Dependency of Bottom Drag and the Eddy Viscosity upon Flow Structure in the Coastal Boundary Layer
Authors: Yao-Zhao Zhong, Hwa Chien, Meng-Yu Lin, Anna Wargula, Jia-Lin Chen
Source: Journal of Marine Science and Engineering, Vol 10, Iss 3, p 324 (2022)
Publisher Information: MDPI AG, 2022.
Publication Year: 2022
Collection: LCC:Naval architecture. Shipbuilding. Marine engineering
LCC:Oceanography
Subject Terms: wave-current interaction, bottom drag, eddy viscosity, coastal boundary layer, Naval architecture. Shipbuilding. Marine engineering, VM1-989, Oceanography, GC1-1581
More Details: The physical processes governing coastal exchange between the surf zone, the inner shelf, and the open ocean is critical for estimating mass exchange and its impact on ecological processes. The present study combined field measurements and theoretical approaches to explore the hydrodynamics in the coastal boundary layer (CBL) in which both bottom drag and shore friction affect the transport and mixing processes. Observed drifter-cluster trajectories in a nearly alongshore-uniform coastal area showed that the occurrence of current reversal varies with cross-shore distance, which confirmed the tidal phase difference between different cross-shore distances predicted by the proposed CBL model. According to the CBL model, tidal phase difference is affected by the bottom drag coefficient and horizontal eddy viscosity coefficient. With the results of three experiments under different wave conditions, this study also discusses the effects of waves on the CBL. Data analysis based on observations indicates that the bottom drag term is closely related to the bottom shear stress induced by the interactions of waves and currents. The bottom drag coefficient under the more energetic wave condition was much greater than that under milder wave conditions during the experiment. The study also suggests that in addition to pressure gradient and bottom drag, flow structure is subject to lateral stress, which reflects the impact of shoreline roughness in the nearshore region and that the estimated eddy viscosity coefficient decreases linearly with distance from the shoreline.
Document Type: article
File Description: electronic resource
Language: English
ISSN: 2077-1312
Relation: https://www.mdpi.com/2077-1312/10/3/324; https://doaj.org/toc/2077-1312
DOI: 10.3390/jmse10030324
Access URL: https://doaj.org/article/0c3165fd9e944af496ee1227cda0b1b7
Accession Number: edsdoj.0c3165fd9e944af496ee1227cda0b1b7
Database: Directory of Open Access Journals
More Details
ISSN:20771312
DOI:10.3390/jmse10030324
Published in:Journal of Marine Science and Engineering
Language:English