Prof. Shar Sajjadi
Dr Sajjadi is a mathematician, theoretical physicist, and applied computational engineers. His main focus of his research currently is the unresolved problems in air-sea interaction by turbulent shear flows due to the wind blowing over the surface of the ocean, particularly during hurricanes. His contributions in this area consist of the growth of unsteady nonlinear waves. He is amongst the very few worldwide scientists who study this subject in depth and received number of international awards.
Turbulence, Waves and Mixing Conference,
King's College, University of Cambridge, UK
July 6-8 2016
IUTAM SYMPOSIUM “WIND WAVES” AT UNIVERSITY COLLEGE LONDON, UK
SEPTEMBER 4-8 2017
EVENTS-RECENT and UPCOMING
Isaac Newton Institute
"Waves and Turbulence"
University of Cambridge
2018 (dates to be confirmed)
MY LATEST RESEARCH
Recently Sajjadi and has showed theoretically that under wind condition a nonlinear wave (such as Stokes wave) become sharp crested and form a wave group. This was confirmed experimentally by his colleague Dr Ludu at the nonlinear wave laboratory. The simulation of air-sea interaction for such groups are currently being studied using numerical methods using a full Differential Second-Moment closure turbulence model with Lord Julian Hunt and Dr. Drullion. They have shown as more energy is transferred to wave by wind waves grow and eventually become sharp-crested. Moreover, as the wave become steeper the cat's-eye (the closed looped on the right-hand diagram) become more asymmetrical.
The first model of growth of surface waves by shear flow was formulated by J.W. Miles in 1957. In this model the critical layer, where the wind speed equals to the wave speed, is totally responsible for the wave growth. In his theory critical layer is confined to the inner layer very close to the wave. But Sajjadi, Hunt and Drullion showed that the critical layer rises up with the wave age and the mechanism of the growth is not only due to the critical layer but more importantly the non-separated sheltering and turbulence.