Professor Sergey A. Gaponov
Khristianovich Institute of Theoretical and Applied Mechanics (ITAM)
SB RAS, 630090, Novosibirsk, RUSSIA
E-mail: gaponov@itam.nsc.ru
Abstract: The receptivity of external
waves and instability of a supersonic boundary layer is considered. It is
well known that unstable hydrodynamic waves can be excited by external waves
in both subsonic and supersonic flows. It has also been established that for
linear interactions of monochromatic waves with laminar flow the excitation
is possible only in nonparallel streams. The distinguishing characteristic
in the generation mechanism of the unstable waves by sound for subsonic and
supersonic flows is as follows: For fixed frequency and low velocities, the
parameter values of sound waves differ considerably from those of unstable
waves. The effective generation of Tollmien-Schlichting (T.-S.) waves takes
place only in the presence of a strong non-homogeneity, e.g., roughness or
the leading edge of the model. However in the case of supersonic flow both
wave parameters are similar. This fact has two consequences. First of all
the sound phase velocity can coincide with the flow velocity in the boundary
layer, and a critical layer appears which leads to strong oscillations in
the boundary layer. Second because sound and T.-S. waves have similar
characteristics their parameters become indistinguishable in nonparallel
flow. Thus effective transmission of oscillatory energy from sound waves
into eigen-oscillations takes place. In this paper both the interaction of
external waves with parallel flow and the possible excitation of eigen-oscillations
in nonparallel flow are considered in linear approach.
The second way of eigen-oscillations excitation is connected with the
non-linear disturbances interaction. In particular two problems are
discussed. In one of them influence of acoustic disturbances wind tunnel on
generation of amplified waves in the modal boundary layer is studied. In the
second example Tollmien-Schlichting waves generation by another frequency
disturbances is investigated.
This work has been financially supported by the RFBR (Grant No.
08-01-00038a)
Brief Biography of the Speaker:
Field of research: Fluid dynamics, laminar- turbulent transition in
wall-bounded shear layers.
Surname: Gaponov First name: Sergey Date of birth: August 20, 1940
Affiliation: Laboratory wave processes in supersonic viscous flows,
Institute of Theoretical and Applied Mechanics of Siberian Branch of Russian
Academy of Science (ITAM SB RAS); Professor at the Department of Theoretical
Mechanics, Novosibirsk State University of Architecture and Civil
Engineering (NSUACE).
Address: Institutskaya Street, 4/1, 630090 Novosibirsk, Russia
Phone: +7(383)3301228, Fax: +7(383)330726 E-mail: gaponov@itam.nsc.ru
Education: Graduated from Physics Department of Novosibirsk State University
(NSU), 1964.
Brief description of professional career (including the title of the
dissertation work, the year and the Institution where it has been defended):
1. Junior and Senior Scientific Researcher, Head of Laboratory of the
Institute of Theoretical and Applied Mechanics SB RAS, January 1965 – till
now.
2. Professor at the Department of Theoretical Mechanics, Novosibirsk State
University of Architecture and Civil Engineering (NSUACE), 1992-till now.
Ph.D. Thesis: "Stability of the Incompressible Boundary Layer on a Permeable
Surface", 1971, Institute of Theoretical and Applied Mechanics of Siberian
Branch of Russian Academy of Science (ITAM SB RAS).
Degree of Doctor (Physics and Mathematics): «Development of disturbances in
a supersonic boundary layer», 1987, Moscow Physical-Technical Institute.
Other fields: Member of Council on Defence of doctoral Thesis’s at Institute
of Theoretical and Applied Mechanics, Member of Russian National Committee
on Theoretical and Applied Mechanics, Prize-Winner of Professor Joukovski
List of recent grants for fundamental research: Grant of International
Science and Technology Center: ISTC-128-96 (1996-1999, investigator). Grants
of Russian Foundation for Basic Research (1994-95, 1996-98, 1999-01,
2002-04, 2005-07, 2008-10, team leader.)
Publications: Number of communications to scientific meetings exceed
hundred. Number of papers in refereed journals is more than130. Two books
were published.
