From the series

Institute of Thermomechanics Seminar:

2D Discrete Spectral Analysis – A Tool for Examining

of Complicated Wave Structures

Prof. Andrus Salupere, Department of Cybernetics, Tallinn University of Technology

Monday, October 2, 2017, 10:00

Conference Room B

V Praze – Ládví vyroste pomník na počest českého fyzika Václava Dolejška (1895-1945) podle návrhu akad. soch. Františka Svátka. Více zde.

6/2017 | 5/2017 |

Starší čísla... |

Institute of Thermomechanics of the CAS is a recipient of project no. CZ.02.1.01/0.0/0.0/15_003/0000493 "Centre of Excellence for Nonlinear Dynamic Behaviour of Advanced Materials in Engineering" (CeNDYNMAT)

Research Area of Mathematics, Physics and Earth Sciences > Section of Applied Physics). The Institute conducts interdisciplinary basic research in fluid dynamics, thermodynamics, dynamics of mechanical systems, solid mechanics, interactions of fluids and solids, environmental aerodynamics, biomechanics, mechatronics, electrophysics, electrical machines, drives and power electronics and material diagnostics.

**Summary**

Dynamic nonlinear elastic behavior, nonequilibrium dynamics, first observed as a curiosity in earth materials has now been observed in a great variety of solids. The primary manifestations of the behavior are characteristic wave distortion, and slow dynamics, a recovery process to equilibrium that takes place linearly with the logarithm of time, over hours to days after a wave disturbance. »»»

Full title: Optimization of coded excitations with Symmetry Analysis : Formalism and applications in NDT with perspectives in ultrasonic nonlinear imaging of bio-materials »»»

In the stability theory of shear layers, the term `local stability' refers to the stability properties of a particular velocity profile at a given position in the flow. When the basic flow develops the streamwise direction, e.g. in a growing boundary layer, the changing local stability properties can be mapped out downstream. If there are regions of local absolute instability then there is the possibility of a `global instability' of the entire flow. When the basic flow varies slowly in the downstream direction the global stability can be determined from the local stability. »»»

Large deformations of a solid are investigated. We use a polar decomposition of gradient matrix F = RW (R is rotation matrix, W is stretch matrix). Large deformations of solids involve local spacial interactions either in an extension or in a rotation. Because local interactions are well described by spacial gradient, matrix W intervene for extensions and matrix gradR intervene for rotations. Thus the free energy depends on W and on gradR. Moreover, free energy takes into account the local impenetrability condition. Reactions to this impenetrability condition are important in constitutive laws. »»»

Turbulence will be introduced as the typical state of real flowing viscous fluids (historical overview). Attributes of turbulence will be presented (diffusivity, deterministic chaos, fractal structure…). A mathematical model will be introduced and its basic properties will be shown including the Kolmogorov theory. Then a few phenomenological aspects will demonstrate the typical features of the phenomenon (stability, complexity…).

The aim of the Colloquium is to facilitate the exchange of up to date information and knowledge among specialists in dynamic of machines and mechanical systems. The main attention will be focused on: »»»

The aim of the conference is to discuss contemporary problems of fluid mechanics and to bring out latest results obtained in the course of solution of grant projects supported by grant agencies in Czech Republic and abroad. The attendance of experts from the academician institutes, technical universities and from the other research institutions is assumed. The official languages of the conference are English and Czech. »»»

Prague November 23-24, 2010 The 11th seminar will discuss the problems of interaction od dynamical systems with the surrounding liquid or gas environment and the problems of dynamic systems with feedback. »»»

The Institute of Thermomechanics AS CR, v.v.i., Prague, the Czech Society for Mechanics and the ERCOFTAC Czech Pilot Centre will organize Colloquium FLUID DYNAMICS 2010 held on October 20 – 22, 2010. »»»

Dr. Hiromasa Nakayama is a researcher in the Japan Atomic Energy Agency, Ibaraki, Japan.

Abstract: There is a potential problem that hazardous and flammable materials are accidentally or intentionally released into the atmosphere, either within or close to populated urban areas. For the assessment of human health hazard from toxic substances, the existence of high concentration peaks in a plume should be considered. »»»

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