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Description of state behavior along the critical isotherm and along the saturation curve using simple equations of state ů part I
Bayer, Zdeněk
The contribution deals with a group of 13 equations of state (EOS), predominantly of the van der Waals type, both classical and also newly developed in the Institute. In the region from the triple- to the critical points, the changes in the temperature functions (1st criterion), deviations of the derivate (2nd criterion), and the course of the liquid spinodal are investigated. Ordinary water substance is used as the model medium. The possibilities of improving EOS of this type are searched. While at separately applied criteria some improvements were arrived at, the simultaneous application of criteria gave no satisfactory results.
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Rotor supported on magnetic bearings - numerical and experimental analysis
Půst, Ladislav ; Kozánek, Jan ; Veselý, Jan
The dynamic properties of rotor supported on passive magnetic bearingsis investigated by means of numerical solution and by measurement on the prototypeof experimental set developed in Institute of Thermomechanics AS CR. Mathematicalmodel was constructed both for linearized part of rotor with bearing and for stronglynonlinear system including impacts in retainer bearings. Comparison with resultsof measurement on prototype enables to ascertain real parameters of linearized partof magnetic bearings.
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Self excited two-mass system with soft impacts
Tondl, Aleš ; Kocanda, Lubomír
To a basic one-mass self-excited system a tuned absorber is attachedthe motion of which is influenced by soft impacts. The self-excitation is consideredas of van der Pol type one. The stops are symmetrically situated to the absorbermass equilibrium position. The results of numerical simulation are presented indiagrams showing the measure of extreme deflection of the basic system mass tothe amplitude of the basic system vibration without absorber in dependence on thetuning coefficient of the absorber.
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Strain gauge measurements of deformations on rubber patterns
Vaněk, František ; Pešek, Luděk ; Cibulka, Jan
This contribution deals with proposal of the method for strain gauge measurements of rubber patterns under dynamic loading. As deform elements the silicon strain gauges were selected. Two calibration test rigs, such as cantilever beam and clamped membrane, were chosen for evaluation of deformation sensitivity of the strain gauges glued at rubber patterns. Material constants of rubber as linear visco-elastic model were evaluated from dynamic tests on the test rigs.
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Finite element modelling of viscous incompressible fluid flow in glottis
Damašek, Alexandr ; Burda, P.
he paper deals with numericalcomputations of viscous incompressible fluid flow in glottis describedby Navier-Stokes equations and discretized bythe finite element method. Navier-Stokes equations with the nonlinearterm are discretized by semiimplicit integration scheme. Forhigher Reynolds number fluid flow Streamline Upwind Petrov-Galerkin Method - SUPG. This method uses special weight functions which modify shape functions based on the Galerkin principle.
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