Corresponding Member Prof. Dr. Stefan Radev is a leading Bulgarian specialist in the field of fluid mechanics. He is the author of over 150 articles in the field of fluid mechanics and the first three-dimensional non-stationary model of a two-layer jet. For over 30 years he has been teaching fluid mechanics at Sofia University and other Bulgarian and foreign universities. He is the director of the Institute of Mechanics of the Bulgarian Academy of Sciences (1986–1992) and the head of the Department of Fluid Mechanics.