School of Mechanical Engineering Dr. Marc Buckley

School of Mechanical Engineering Seminar
Monday, July 2, 2018 at 14:00
Wolfson Building of Mechanical Engineering, Room 234

The influence of waves on the air-sea momentum flux

Dr. Marc Buckley

Institute of Coastal Research, Helmholtz-Zentrum Geesthacht, Germany

The transfers of momentum and scalars across the air-sea interface are influenced by small-scale turbulent processes. In spite of extensive existing work on the topic, our understanding of near-surface physics remains incomplete. This is partly due to the technical challenges involved in the measurement of the small-scale dynamics very close to the rapidly moving ocean surface. We present new in situ measurements of the submillimeter-scale motions in the airflow above waves. A high resolution, large field of view Particle Image Velocimetry (PIV) system was specially developed for measurements at the ocean surface, capable of capturing 2D velocity fields in the turbulent airflow directly above the wavy surface. The system was recently deployed on RP FLIP. Using preliminary field measurements as well as laboratory wave tank measurements, we will discuss the impact of waves on the structure of the wind stress within the wave boundary layer, and in particular how breaking and non-breaking waves influence the momentum flux's partitioning between viscous, form drag, wave-coherent and turbulent contributions.