Turbulent Flow over Steep Steady and Unsteady Waves under Strong Wind Forcing

• DOI: 10.1175/jpo-d-17-0118.1
• Publication Date: 2017-10-17T21:00:56Z
• Authors: Peter P. Sullivan; Michael L. Banner; Russel P. Morison; William L. Peirson
• Keywords: Wind Stress; Crest

Abstract Turbulent flow over strongly forced steep steady and unsteady waves is simulated using large-eddy simulation (LES) with time t space x varying wave height h ( , ) imposed as a lower boundary condition. With waves, based on measurements of incipient active breaking collected in wind-wave flume, while numerical code used to generate an evolving packet (group). Highly intermittent airflow separation found the simulations, results suggest near crest occurs prior onset breaking. The form (pressure) drag most sensitive slope, can contribute much 74% total stress. Wind scalar profiles from LES display log-linear variations above surface; wind are good agreement measurements. momentum roughness increases water surface changes ripples However, decreases becomes rougher. This highlights major differences transport rough wavy surface. For rapidly evolving, group, highly correlated early evolution when local slope −∂ /∂ ≥ 0.22. root-mean-square 0.084, but fraction 2.4 times larger than comparably wave. Thus, passing group induce unsteadiness