Research | Air-Flow Separation
 
 
Airflow separation is thought to be one of the factor contributing to very high wind speeds in hurricanes. We observe and measure separation above surface gravity waves in the lab and the field and directly measure the surface stress.
The coupled air-sea boundary layers play an important role in the multiple fluxes between the ocean and the atmosphere. In particular the stress (drag) on the ocean's surface is a crucial parameter for both short term forecasting and the modeling of long-term global climate trends. However, the effects of airflow separation are not well understood. For example, while hurricane track forecasts have significantly improved in the past few years, hurricane intensity forecasts are essentially unchanged since 1970! This is in part due to our lack of understanding of the complex physics involved in the air-sea fluxes of momentum when airflow separation is present. The proposed research program is concerned with the role of airflow separation in influencing the air-sea momentum flux. Specifically, we perform laboratory and field experiments and examine the detailed structure of the separated airflow above the waves in order to determine
  • What processes and factors (wavelength, slope, phase, asymmetry...) lead to airflow separation,
  • And assess the impact of airflow separation on the air-sea momentum balance.
The figure above shows the velocity magnitude above a wind wave measured using high resoltuion particule image velocimetry (PIV) in the laboratory. We can clearly identify a separated region on the less side of the wave.
 
Air-Sea Interaction Laboratory | Newark & Lewes, DE USA
Phone: 302-831-6658| Email: airsealab@udel.edu
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