Yury Stepanyants graduated in 1973 with the Higher Distinction Diploma of the MSc from the Gorky State University (Russia) and started to work as an Engineer with the Research Radio-physical Institute in Gorky. Then he proceeded his career at the Institute of Applied Physics of the Russian Academy of Sciences (Nizhny Novgorod, Russia) taking successively the positions of Junior, Senior and Leading Research Scientist from 1977 to 1997. In 1983 Yury obtained a PhD in Physical Oceanography, and in 1992 he obtained the highest scientific degree of Doctor of Sciences in Geophysics. In 1995 he was granted the title of Professor of Applied Mathematics in Russia, and in 2004 – the title of Professeur des Universités in Mécanique in France. After immigrating to Australia in 1998, Yury worked for 12 years as the Senior Research Scientist with the Australian Nuclear Science and Technology Organisation (Sydney). Since July 2009 he has been working at the University of Southern Queensland (Toowoomba) holding positions of Associate Professor (2009–2014) and the Full Professor in Applied Mathematics (from 2014 until now).
Yury made important contributions to several fields including:
– nonlinear wave processes in discrete structures: soliton generation and their interaction,
stochastisation of chains of coupled oscillators by an external force, Cherenkov radiation from
moving solitons, plane soliton interaction;
– shear flow instability in stratified fluids: derivation of instability conditions, generalisa-
tion of Miles–Howard theorems; development of a concept of negative energy waves (NEW) in
hydrodynamics and interpretation of classical theorems of hydrodynamic theory of instability in terms of the NEW concept; description of the nonlinear stage of instability of long waves in a stratified ocean; jointly with A.L. Fabrikant has published a book “Propagation of waves in shear flows” (World Scientific, 1998);
– vortex motions in viscous and stratified fluid: constructed exact solution for the descrip-
tion of acoustic-gravity modons in the atmosphere; investigated monopole and dipole (Chap-
lygin–Lamb) vortices with each other and with a rigid wall in a viscous fluid; has discovered instability of Chaplygin–Lamb vortices with a complex internal structure; calculated a lateral force acting on vortices on a beta-plane and found an instability of west-ward motion of Larichev–Reznik vortices on a beta-plane; developed a theory of bath-type vortices in a fluid draining through the bottom orifice and found the condition when the gaseous core can be entrapped into the orifice;
– nonlinear wave theory: has studied dynamical and stochastical interactions of one- dimensional solitons and two-dimensional lumps; jointly with co-authors, he found exact solutions to the Kadomtsev–Petviashvili equation describing multi-lump structures, investigated their stability and interaction with each other, has discovered a new type of anomalous lump interaction; has investigated the interaction of lumps and lump chains with each other and with plane solitons;
– wave-current interactions: developed a theory of wave scattering in canals of nonuniform
cross-sections with spatially varying currents; on the basis of a known similarity between the hydrodynamic equations and equations of general relativity, has calculated the spectrum of scattered waves corresponding to Hawking radiation from black holes; has found conditions of reflectionless wave propagation in nonuniform canals with spatially variable currents; has calculated surface wave scattering on a vortex in a draining fluid and demonstrated that scattered waves can be amplified by a vortex; this demonstrates a possibility to wave amplification by rotating black holes.