Download JTAM-2-2013_ABSTRACTS

FOREWORD TO THE SPECIAL ISSUE
devoted to 70th Anniversary of Prof. Stefan Radev,
Corresponding Member of the Bulgarian Academy of Sciences
CITATION OF FIVE TECHNICAL PAPERS PUBLISHED
IN JOURNAL OF THEORETICAL AND APPLIED
MECHANICS, Vol. 42, No. 1 AND 2 PUBLISHED WITH
THE FINANCIAL SUPPORT OF PROJECT
BG051PO001–3.3.05.–0001 “SCIENCE AND BUSINESS”,
FUNDED ON OPERATIONAL PROGRAM
“DEVELOPMENT OF HUMAN RESOURCES” AT THE
“EUROPEAN SOCIAL FUND”
St. Radev
Institute of Mechanics, Bulgarian Academy of Sciences,
Acad. G. Bonchev St., Bl. 4, 1113 Sofia, Bulgaria,
e-mail: [email protected]
F. R. A. Onofri, A. Lenoble, L. Tadrist
IUSTI UMR 7343 CNRS/Aix-Marseille University,
5 r. E. Fermi, Technopˆole de Chˆateau Gombert, Marseille 13453, France,
e-mails: [email protected], [email protected],
[email protected]
REVIEW ON THE INSTABILITY AND OPTICS
OF CAPILLARY JETS AND GLASS FIBRES:
A FRUITFULL COLLABORATION BETWEEN
INSTITUTE OF MECHANICS AND IUSTI
Abstract. The paper review key results [1-14] of the joint researches conducted by IMech and
IUSTI. In the First part, we review models and experimental results on the linear and nonlinear
instability of a capillary jet including both axisymmetric and nonaxisymmetric disturbances. In
the Second part, results on draw resonances, occurring during a glass fibre process are reviewed,
as well as the unique optical models and methods developed to perform these studies.
Zlatinka I. Dimitrova
“G. Nadjakov” Institute of Solid State Physics, Bulgarian Academy of Sciences,
71, Tzarigradsko Chaussee Blvd, 1784 Sofia, Bulgaria,
e-mail: [email protected]
Kaloyan N. Vitanov
Faculty of Mathematics and Informatics, “St. Kliment Ohridski” University of Sofia,
5, J. Bourchier Blvd, 1164 Sofia, Bulgaria,
INTEGRABILITY OF DIFFERENTIAL EQUATIONS WITH
FLUID MECHANICS APPLICATION: FROM PAINLEVE
PROPERTY TO THE METHOD OF SIMPLEST
EQUATION
Abstract. We present a brief overview of integrability of nonlinear ordinary and partial
differential equations with a focus on the Painleve property: an ODE of second order possesses
the Painleve property if the only movable singularities connected to this equation are single
poles.
The importance of this property can be seen from the Ablowitz-Ramani- Segur conhecture that
states that a non-linear PDE is solvable by inverse scattering transformation only if each
nonlinear ODE obtained by ex- act reduction of this PDE possesses the Painleve property. The
Painleve property motivated much research on obtaining exact solutions on non-linear PDEs and
leaded in particular to the method of simplest equation. A version of this method called modified
method of simplest equation is discussed below.
Nikolay K. Vitanov
Institute of Mechanics, Bulgarian Academy of Sciences,
Acad. G. Bonchev St., Bl. 4, 1113 Sofia, Bulgaria,
e-mail: [email protected]
Amin Chabchoub, Norbert Hoffmann
Institute of Mechanics and Ocean Engineering,
Hamburg University of Technology, 21073 Hamburg, Germany,
e-mails: [email protected], [email protected]
DEEP-WATER WAVES: ON THE NONLINEAR
SCHR¨ ODINGER EQUATION AND ITS SOLUTIONS
Abstract. We present a brief discussion on the nonlinear Schr¨odinger equation for modelling
the propagation of the deep-water wavetrains and a discussion on its doubly-localized breather
solutions, that can be connected to the sudden formation of extreme waves, also known as rogue
waves or freak waves.
Baljeet Singh
Department of Mathematics, Post Graduate Government College,
Sector 11, Chandigarh-160 011, India,
e-mail: [email protected]
Ranbir Singh
Department of Mathematics, Modern Institute of Engineering and Technology,
Ambala, Haryana, India,
e-mail: [email protected]
RAYLEIGH WAVE IN A ROTATING INITIALLY
STRESSED PIEZOELECTRIC HALF-SPACE
Abstract. The governing equations of an initially stressed rotating piezoelectric medium are
solved for surface wave solutions. The appropriate solutions in the half-space of the medium
satisfy the required boundary conditions to obtain the frequency equation of Rayleigh wave for
charge free as well as electrically shorted cases. The non-dimensional speed of the Rayleigh
wave is computed numerically for particular examples of Lithium niobate and PZT-5H ceramics.
The effects of rotation and initial stress are observed graphically on the non-dimensional speed
of the Rayleigh wave.
Ivan Jordanov, Elena Nikolova
Institute of Mechanics, Bulgarian Academy of Sciences,
Acad. G. Bonchev St., Bl. 4, 1113 Sofia, Bulgaria,
e-mails: [email protected], [email protected]
ON NONLINEAR WAVES IN THE SPATIO-TEMPORAL
DYNAMICS OF INTERACTING POPULATIONS
Abstract. In this paper the spatial-temporal dynamics of the members of interacting populations
is described by means of nonlinear partial diff erential equations. We consider the migration as a
diff usion process influenced by the changing values of the birth rates and the coefficients of
interaction between the populations. The general model is reduced to analytically tractable
partial diff erential equations (PDE) with polynomial nonlinearity up to third order for the
particular case of one population and one spatial dimension. We obtain an analytical solution
which describes nonlinear kink and solitary waves in the population dynamics by applying the
modified method of simplest equation to the described model.
Key words: Population dynamics, migration, partial diff erential equations (PDEs), modified
method of the simplest equation, kinks.
Cristian Puscasu, Mihaela Grigorescu, Axene Ghita, Raluca
Voicu, Mariana Stefanescu, Victoria Teleaba
National Research & Development Institute for Gas Turbines COMOTI,
I220D, Iuliu Maniu Avenue, sector 6,
Code 061126, OP76, CP 174, Bucharest, Romania,
e-mail: [email protected]
Ivanka Zheleva,
Ruse University “Angel Kanichev”,
8, Studentska Street, 7017, Russe, Bulgaria,
e-mail: [email protected]
SIMULATION OF FLUID FLOW IN CENTRIFUGAL
TRICANTER
Abstract. An ANSYS simulation of the multiphase complex fluid flow motion in a centrifugal
device (tricanter) is presented in the paper. This centrifugal device is designed for one step
efficient solution for contaminated river water processing with oil and oil products. The
proposed tricanter is one of the main objectives of the project named “Common strategy to
prevent the Danube’s pollution technological risks with oil and oil products CLEANDANUBE”
financed by European Commission within the frame of Romania-Bulgaria Trans-Border
Cooperation Program 2007 – 2013 (grant MIS-ETC code 653). Results for liquid phases (water
and oil products) and for solid particles motion are presented graphically and are commented.
S. Slavtchev, P. Kalitzova-Kurteva
Institute of Mechanics, Bulgarian Academy of Sciences,
Acad. G. Bonchev St., Bl. 4, 1113 Sofia, Bulgaria,
e-mails: [email protected], [email protected]
A. Oron
Department of Mechanical Engineering, Technion-Israel Institute of Technology,
Haifa 32000, Israel,
e-mail: [email protected]
EVOLUTION EQUATION FOR NONLINEAR
LONG-WAVELENGTH MONOTONIC MARANGONI
INSTABILITY IN A BINARY LIQUID LAYER WITH
NONLINEAR SORET EFFECT
Abstract. The Soret effect in binary systems is called nonlinear when the thermo-diffusive flux
is proportional to the temperature gradient with a coefficient being linear function of the
concentration of one of the solute components. This effect is significant in highly dilute
solutions. The long- wavelength Marangoni instability in a thin layer of binary liquid, in the
presence of the nonlinear Soret effect, is considered. The nonlinear dynamic behaviour of the
liquid system is studied in the case of monotonic instability. The solution of the dimensionless
equations of mass and momentum balances, heat transfer and mass diffusion is searched near the
linear instability threshold, in the form of series in a small parameter that measures the
supercriticality. An equation for spatiotemporal evolution of the liquid system is derived based
on the first two approximations.
PROF. STEFAN RADEV,
CORRESPONDING MEMBER OF THE BULGARIAN
ACADEMY OF SCIENCES AND HIS CONTRIBUTIONS
TO FLUID MECHANICS