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ANALYTIC FORMULAE FOR THE CONSTRUCTION OF SYMMETRIC DYNAMICAL SYSTEMS
Kozánek, Jan
In this paper the formulae for complex modal matrix and symmetric regular stiffness matrix and symmetric matrix of viscous damping from real, positive definite mass matrix and from diagonal spectral matrix were deduced. Because of the non-unicity of this problem, the solution is based on the fact, that the helping matrix has the same ratio of the eigenvalues as the inversion of given mass matrix. Finally, the resolvent of this symmetric system was expressed in simple additive form.
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ANALYTIC FORMULAE FOR THE CONSTRUCTION OF NON-DIAGONALIZABLE DYNAMICAL SYSTEMS
Kozánek, Jan
In this paper the formulae for regular stiffness matrix and matrix of viscous damping and for complex left modal matrix from regular mass matrix, nondiagonal jordan matrix with one complex eigenvalue of multiplicity 2 and from complex right modal matrix were deduced. Finally, the resolvent of this system was expressed in additive form. The corresponding formulae for dynamical systems with commutative matrix of viscous damping and with real right modal matrix were given, too.
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ANALYTIC FORMULAE FOR THE CONSTRUCTION OF DIAGONALIZABLE DYNAMICAL SYSTEMS
Kozánek, Jan
In this paper the formulae for regular stiffness matrix and matrix of viscous damping and for complex modal matrix of left eigenvectors from regular mass matrix, diagonal spectral matrix and from complex modal matrix of right eiegenvectors was deduced. Finally, the resolvent of this system was expressed in simple additive form. The corresponding formulae for dynamical systems with commutative matrix of viscous damping and with corresponding real modal matrix of right eigenvectors was given, too.
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PROPOSITION OF THE DIFFERENTIAL FEEDBACK CONTROL OF ROTOR’S POSITION FOR CONTACTLESS SUPPORT
Kozánek, Jan ; Synek, L. ; Sýkora, Petr
This paper proposes a differential method for the position control of electromagnetic actuator. The differential method is frequently used by active magnetic bearing in industrial application too. The controller is consisted of position regulator and two current regulators with auxiliary differential part, where is counted a difference between biases current and position current. Thus the controller contains a current feedback and a position feedback. The current feedback is used as current control into exciting coil and the air-gap is measured by an eddy current position sensor. The position stabilization of the contactless rotor is provided by suitable analogue regulator.
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Numerické simulace interakce proudu s leteckým profilem se třemi stupni volnosti
Růžička, M. ; Feistauer, M. ; Horáček, Jaromír ; Sváček, Petr
The subject of the paper is the numerical simulation of the interaction of two-dimensional incompressible viscous fluid and a vibrating airfoil with large deviations. The airfoil is considered as a solid body with three degrees of freedom. The airfoil performs rotation around an elastic axis, oscillations in the vertical direction and rotation of a flap. The nemerical simulation is based on the the finite element solution of the Navier-Stokes equations and the system of nonlinear ordinary differential equations deseribing the airfoil motion. The interaction and feedback phenomenon is numerically treated by a coupling procedure, which connects the structural problem and flow problem together. The timedependent computational domain and a moving mesh are taken into account with the aid of the Arbitrary Lagrangian-Eulerian (ALE) formulation. High Reynolds numbers up to 10 require the application of a suitable stabilizatin of the finite element discretization.
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Pěvecký formant: Předběžné výsledky vyhodnocení snímků z magnetické rezonance a akustických záznamů při fonaci zpěváků
Švec, J. ; Herbst, C. ; Havlík, R. ; Horáček, Jaromír ; Krupa, P. ; Lejska, M. ; Miller, D.G.
Singerś formant is a desirable quality in operatic singing. This study investigates the strategies of two male operatic singers used for achieving the singerś formant. The subjects were asked to produce voice both in naïve and operatic singing quality at the same fundamental frequency for two different vowels [a] and [e]. Changes in the shape of the vocal tract were investigated using magnetic resonance imaging (MRI), and differences in acoustic voice quality were analyzed using sound spectrography. In operatic voice quality the MR images revealed a) lowered larynx, b) raised soft palate, c) flattened tongue and d)straightened spine. Clustering and lowering the formant frequencies was seen in the spectrograms but the strategy was different for the two vowels and the two singers. The data suggest that different anatomical dispositions in singers lead to different strategies for optimizing the voice quality.
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Numerické simulace stlačitelného proudění v kanále s pohyblivou stěnou
Prokopova, J. ; Feistauer, M. ; Kučera, V. ; Horáček, Jaromír
This work is concerned with the simulation of inviscid compressible flow in time dependent domains. The special treatment is given to the ALE (Arbitrary Lagrangian-Eulerian) method. We present an ALE formulation of the Euler equations describing the compressible flow and discretize them. The space discretize them. The space discretization is carried out by the discontinuous Galerkin method and for the time discretization a semi-implicit scheme is used. In the end of the paper some computational results are presented.
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