Evidence of the critical layer mechanism in growing wind waves

Highly resolved laboratory measurements of the airflow over wind-generated waves are examined using a novel wave growth diagnostic that quantifies the presence of Miles’ critical layer mechanism of wind-wave growth. The wave growth diagnostic is formulated based on a linear stability analysis, and r...

Full description

Saved in:
Bibliographic Details
Published in:Journal of fluid mechanics 2022-10, Vol.948, Article A26
Main Authors: Carpenter, J.R., Buckley, M.P., Veron, F.
Format: Article
Language:English
Subjects:
Air flow
Diagnostic systems
Eigenvalues
Experiments
Growth rate
JFM Papers
Laboratories
Ordinary differential equations
Phase velocity
Significant waves
Stability analysis
Velocity
Wave phase
Wave power
Wind
Wind waves
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Highly resolved laboratory measurements of the airflow over wind-generated waves are examined using a novel wave growth diagnostic that quantifies the presence of Miles’ critical layer mechanism of wind-wave growth. The wave growth diagnostic is formulated based on a linear stability analysis, and results in growth rates that agree well with those found by a pressure reconstruction method as well as other, less direct, methods. This finding, combined with a close agreement between the airflow measurements and the predictions of linear stability (critical layer) theory, demonstrate that the Miles’ critical layer mechanism can cause significant wave growth in young (wave age $c/u_* = 6.3$, where $c$ is the wave phase speed, and $u_*$ the friction velocity) wind-forced waves.
ISSN:0022-1120
1469-7645
DOI:10.1017/jfm.2022.714